dnvgl-se-0124 certification of grid code compliance · pdf file3.2.4 modeling of simulation...

SERVICE SPECIFICATION

DNVGL-SE-0124 Edition March 2016

Certification of grid code compliance

DNV GL AS

The electronic pdf version of this document found through http://www.dnvgl.com is the officially binding version. The documents are available free of charge in PDF format.

FOREWORD
DNV GL service specifications contain procedural requirements for obtaining and retaining certificates andother conformity statements to the objects, personnel, organisations and/or operations in question.
© DNV GL AS March 2016

Any comments may be sent by e-mail to [email protected]

This service document has been prepared based on available knowledge, technology and/or information at the time of issuance of this document. The use of thisdocument by others than DNV GL is at the user's sole risk. DNV GL does not accept any liability or responsibility for loss or damages resulting from any use ofthis document.

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Service specification, DNVGL-SE-0124 – Edition March 2016

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Contents
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Sec.1 General ......................................................................................................... 61.1 Introduction ...........................................................................................61.2 Objective................................................................................................61.3 Scope of this service specification..........................................................61.4 Application .............................................................................................71.5 Glossary ................................................................................................9

1.5.1 Terms and definitions .....................................................................91.5.2 Acronyms and latin letters ............................................................211.5.3 Subscripts...................................................................................231.5.4 Verbal forms ...............................................................................231.5.5 References..................................................................................23

Sec.2 Procedural requirements............................................................................. 262.1 The procedure from quotation to certification (type of unit) ................262.2 Grid code compliance services for evaluating plants or modules

(site specific) .......................................................................................262.3 National requirements..........................................................................26

2.3.1 Legal requirements in the European Union.......................................272.3.2 Great Britain ...............................................................................272.3.3 Greece .......................................................................................272.3.4 Spain and Portugal.......................................................................272.3.5 Germany ....................................................................................272.3.6 South Africa ................................................................................272.3.7 China ........................................................................................282.3.8 India ..........................................................................................282.3.9 Multi-national grid code approach (GCC-class TCII)...........................28

2.4 Other procedural requirements ...........................................................282.4.1 Validity of tests............................................................................282.4.2 Assessment according to outdated technical notes for grid code

compliance..................................................................................292.4.3 Customer - DNV GL interaction ......................................................292.4.4 Certification requirements, quality management...............................292.4.5 Documentation requirements.........................................................29

Sec.3 Description of grid code compliance services .............................................. 303.1 Phase 1 - Definition phase....................................................................30

3.1.1 Overview ....................................................................................303.1.2 Grid code compliance service for pre-screening requirements.............303.1.3 Defining assessment scope for each grid code compliance service.......31

3.2 Phase 2 – Verification phase ................................................................333.2.1 Overview ....................................................................................333.2.2 Test plan preparation ...................................................................343.2.3 Verification testing .......................................................................353.2.4 Modeling of simulation models and parameter adaption ....................353.2.5 Simulation model validation against hardware test ...........................35

3.3 Phase 3 – Certification phase ...............................................................363.3.1 Overview ....................................................................................363.3.2 Evaluating compliance ..................................................................373.3.3 Grid code compliance – certification................................................403.3.4 Compliance monitoring .................................................................42


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3.4 Service details summary and deliverables overview.............................42
3.5 Inspection ............................................................................................45


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SECTION 1 GENERAL
1.1 IntroductionThis service specification defines procedural requirements for obtaining and maintaining third party confirmation of evaluated verification results (GCC services) classified in different verification levels, the so called GCC-classes. Such proof can be a certificate or other compliance documents.

An overview for GCC services can be found in [1.4], details and references in [3.4], related compliance documents and reports are listed in [3.3]. All this is finally based on technical assessment, test, validation and simulation concerning the above described proof of evidence. Details on the test, measurement, assessment, validation and simulation can be found in DNVGL-ST-0125 /1/.

The numbers in brackets [x] denote the section numbers x e.g. with more detailed descriptions of the services, the numbers y in backslash /y/ denotes the references listed in a comprehensive glossary in [1.5] containing also terms, definitions and abbreviations.

1.2 ObjectiveGrid code compliance services (GCC services) provide proof of evidence that grid codes are fulfilled, i.e. that units, plants, modules and facilities are compliant with the requirements regarding the electrical behaviour set out in the grid codes.

GCC services are intended for rating the quality of electricity generated from renewable energy resources with respect to the impact the generation has on the electricity grid by the equipment under assessment and verification. The quality assessed is related to electrical performance and capability of electrical equipment and also to requirements coming from system operators and governmental institutions with the aim of ensuring security of supply of electricity from renewable energy resources (RES) and other distributed energy resources (DER) by units grouped in plant structured by system operators to modules and facilities (see Figure 1-3, Figure 1-4 showing the module and Figure 1-2 explaining the definition of facility).

Modern plants are designed to support the electrical power grid (in the following called system or network) with ancillary services during normal operation as well as during electrical faults in the system. Such support is achieved by additional features of the units and plants in order to help system operators keeping distribution and transmission systems in safe operational mode ensuring security of supply. These features are called GCC features. GCC features define the ancillary services each unit or plant is able to provide in the way that the system operator is expecting it.

GCC services as described in this service specification make it possible to prove, that grid code requirements are fulfilled. This will be based on assessment of the implementation of corresponding GCC features in units, plants, modules and facilities. The GCC features make it possible to provide corresponding ancillary services. Such ancillary services can be delivered by units and plants in feeding them into the modules and facilities of the electrical power system in order to fulfil the grid code requirements. Requirements are coming e.g. from electricity system operators, this document shows how to proof and how to handle them (see [3.1.3]).

1.3 Scope of this service specificationDNV GL’s GCC services are advising what requirements are to be taken from which grid code, how to provide evidence of compliance by testing and measuring technical capabilities of units and plants and how to evaluate the results and to state the compliance with certain requirements in different levels (GCC-classes).

The certification concepts for grid code compliance as detailed below constitute robust means to provide evidence of compliance and give corresponding confirmations to stakeholders (owners, financiers, partners, utility and insurance companies, the public, governmental and non-governmental organizations) by independent verifications.

The project certification concept [3.3.3] gives confirmation that relevant local requirements for the plant or module are met. This is granted by listing the set of local requirements and by the corresponding


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assessment. The project certificate also confirms that corresponding compliance is valid for the site and
verified independently. Local requirements are depending on the GCC-class as described in [3.1.3] and sometimes they are given in site specific documents usually issued by the relevant network operator (RNO).

The type certification concept provides the same for a type of unit.

Other GCC services can be provided as well. The scope of requirements to be considered, the data basis for the assessment and the different verification levels are defined and described in [3.1] and thereafter.

The service specification describes the activities which are necessary to be carried out to obtain a DNV GL certificate for grid code compliance or other deliverables which are also defined within this document. The service specification additionally describes how to agree upon the assessment level and the scope of assessment, as this can be chosen by the customer via different GCC-classes whether it shall prove full acceptance of a specific system operator or if the maximum capability concerning a set of well-defined GCC features shall be verified.

1.4 ApplicationCertification of a unit, plant or module concerning grid code compliance (GCC) is subdivided into three phases with two or three steps per phase as detailed below in Figure 1-1.

Figure 1-1 GCC certification

All relevant items of phase 1 (definition phase) shall be completed before starting services of phase 2 (“verification phase”) is possible.

Details can be found in [3.4].


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Phase 1. Definition phase (see [3.1])

a) pre-screening, technical market investigation (see [3.1.2])b) decision about verification and assessment scope (see [3.1.3]).

Phase 2. Verification phase (see [3.2])

a) test plan (see [3.2.2])b) tests, measurements, post-processing, reporting (see [3.2.3])c) simulation model preparation or parameter adaption (see [3.2.4])d) simulation model validation against hardware test results (see [3.2.5]).

Phase 3. Certification phase (see [3.3])

a) assessment for evaluation of compliance (see [[3.3.2]b) issue of the certificate according to the decision in the definition phase (see [[3.3.3])c) compliance monitoring (see [3.3.4])

For services in phase 2 (verification phase) phase 1 step a) should be completed (pre-screening) but step b) (decision about verification and assessment scope) shall be completed.

For services in certification phase all steps of verification phase shall be completed.

Further details about the phases can be found in Sec.3 (see Figure 3-1, Figure 3-2 and Figure 3-3) and summarized in Table 3-3 in [3.4].

The content of this service specification shall be applied to equipment intended to be used for the conversion of available energy to electrical power by using renewable sources like wind, solar radiation, bio fuels, water, storage systems or others. The equipment has to be compliant with grid code requirements set by system operators, governments or others.

This service specification is applicable to all types of energy converting equipment like units, plants, modules or any other electrical equipment. It can be applied for fulfilling parts of other standards or service specifications as e.g. /2/, /3/ (wind) and especially /4/ (solar), see [1.5.5]).

In some countries, system operators require to establish evidence that units are compatible with the requirements of their grid codes in order to be connected to the grid (see [2.3] and /21/). In other countries only plants are required to be certified. However, both should be certified, the unit as well as the plant, the module and the facility if system operators finds it helpful, too.

Guidance note:In most countries only plants or modules can be compliant with grid codes, not the units. This is due to the focus of system operators on plants and modules with aggregated power and another reason is that the power plant structure is usually not within the responsibility of the system operator but it is the power plant operator’s responsibility (or the operator of the module or facility). Nevertheless this service specification for GCC services shows a way, how types of units can show grid code compliance by defining assumptions which have to be implemented on plant and module level. Compliance with grid codes can be shown best by grid code compliance certification of both, unit and plant.

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1.5 Glossary
1.5.1 Terms and definitionsTerms and definitions in this section are not generic definitions but they are formulated specifically in the intension as used in this service specification.

Table 1-1 Terms and definitions

Term Definitionactive power electrical active power, under periodic conditions, mean value, taken over one period T, of the

instantaneous power p:

Remark 1 Under sinusoidal conditions, the active power is the real part of the complex power. Remark 2 The SI unit for active power is the watt /6/.

asset physical or logical object owned by or under the custodial duties of an organization, having either a perceived or actual value to the organization Remark: In the case of industrial automation and control systems the physical assets that have the largest directly measurable value may be the equipment under control /29/.

assessment prior to evaluating any technical context it is necessary to understand the facts and the relation between the different aspectsThis is called assessment and corresponding measures can be different from case to case. Examples are investigating, reading and understanding descriptions, examine drawings, listings, simulating different cases after validating simulation models, checking calculations or measurement results from corresponding testing, questioning plausibility, verifying assumptions etc. In general assessment means undertaking of an investigation in order to arrive at a judgment, based on evidence, of the suitability of a product /32/.

ancillary services functional capabilities of electrical equipment serving the electrical system as required by the relevant network operator (RNO) Within this service specification ancillary services can be specified by GCC features, e.g. frequency control (D5 as detailed in the Appendix to DNVGL-ST-0125 /1/).‘Ancillary services’ refers to a range of functions which TSOs contract so that they can guarantee system security. These include black start capability (the ability to restart a grid following a blackout); frequency response (to maintain system frequency with automatic and very fast responses); fast reserve (which can provide additional energy when needed); the provision of reactive power and various other services as required in the grid codes, all detailed in the Appendix of the standard GCC /1/.

automatic voltage control

the capability to regulate a specific power system voltage, via adjustment of unit excitation within the limits of unit terminal voltage and VAR capability /38/This can be performed by an automatic voltage regulator (AVR), a continuously acting automatic equipment controlling the terminal voltage of an asset, equipment, plant or unit by comparing the actual terminal voltage with a reference value and controlling by appropriate means the output of an excitation system, depending on the deviations.

black start capability an ancillary service usually not required from wind turbines or PV inverters - is the capability of recovery of a module from a total shutdown through a dedicated auxiliary power source without any energy supply which is external to each plant, equipment or asset within this module

certificate proof of evidence of compliance based on independent assessment issued by DNV GL’s certification body Renewables Certification

certification action by a certification body, providing written assurance that adequate confidence is provided that the asset in question is demonstrably in conformity with a specific standard or other normative documentCertification is the final statement that all requirements of a standard or normative document have been satisfied or conformed to.(ISO 17000:2004): third-party issue of a statement, based on a decision following review, that fulfilment of specified requirements has been demonstrated related to products, processes or systems. Review shall in this context mean a documented, comprehensive and systematic examination of a product, process or system to evaluate its compliance with the specified requirements. Specified requirements refer to a need or expectation that is stated in normative documents such as national or international standard or DNV GL service specification.

P = 1T T 0 p t ∗ dt


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certification phase see “phase”certification procedure also called certification scheme, i.e. a sequence of phases or modules to be completed prior to

the issue of a certificate, [3.3.3] is the main certification procedure related to this service specification

certification report see [3.3.3], verification report with additional credibility due to assessment made strictly according to certification procedures by DNV GL’s certification body Renewables Certification, which is correspondingly accredited

closed distribution system operator

within EU area: (CDSO) is a natural or legal person operating, ensuring the maintenance of and, if necessary, developing a closed distribution network according to article 28 of directive 2009/72/CE /36/

combustion engine is an engine which generates mechanical power by combustion of a fuel, here: power generating unit with combustion engine (gen-set)

compliance monitoring the process of verifying that the (technical) capabilities of modules are maintained compliant by the facility owner with the specifications and requirements of the scope to be defined according to [3.3.4]

compliance simulation compliance simulation is part of the process of verifying that modules are compliant with the specifications and requirements of the network code /35/, for example before starting their operationThis is part of the process according to the coming EU commission regulation /35/ see [1.5.5]. The verification shall include, inter alia, the revision of documentation, the verification of the requested capabilities of the module by simulation studies and the revision against actual measurements (model validation acc. to [2.1.2] of DNVGL-ST-0125 and [3.3.2] here).

compliance testing the process of verifying the compliance of modules with the specifications and requirements of the future EU commission regulation /35/ (see [1.5.5]), for example before starting their operation The verification includes, inter alia, the review of documentation, the verification of the requested capabilities of the module by practical tests according to test plan (see Sec.3 in DNVGL-ST-0125 /1/ as listed in [1.5.5] and [3.2.3] within this service specification).

component main part of an asset, a plant, a unit or any equipment component certificate see [3.3.3]conformity statement statement of compliance – for statement level (IEC: conformity statement)

A conformity statement is issued to confirm that the verification process has concluded that the object complies with the specified requirements.

connection agreement is a contract between the RNO (relevant network operator) and the facility owner which includes the relevant site and technical specific requirements for the facility

connection point the point at which the power plant is connected with the grid of the grid operator (generally the point at which the circuit breaker, meter and protection relays are installed)Within EU area: The interface at which the module is connected to a transmission, distribution or closed distribution network according to Article 28 of Directive 2009/72/CE /36/ as identified in the connection agreement.

control area a control area is defined as a power system, a part of a system or a combination of systems to which a common generation control scheme is appliedThe electrical interconnections within each control area are very strong as compared to the ties with the neighboring areas. The RNO is usually technically responsible for his control area.

control function some GCC features according to Appendix are related to control of other GCC features Such control functions are typically performed by plant control which can be separate equipment, integral part of units or even cascaded control equipment on plant, module, or even facility level. Part of control functions may be performed by system operators, e.g. in providing corresponding signals for set-point or mode selection purposes.

cost-benefit analysis a process by which the RNO weighs the expected costs of alternative actions aiming at the same objective against the expected benefits in order to determine the alternative with the highest net socio-economic benefitIf applicable, the alternatives include network-based and market-based actions, e.g. using validated simulation models according to [3.2.5].

current electrical current is - unless stated otherwise - the current referring to the root-mean-square value of the positive sequence of the phase current at fundamental frequency

Table 1-1 Terms and definitions (Continued)

Term Definition


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customer DNV GL’s contractual partner It may be the manufacturer, its supplier, an EPC company, the developer, the operator or any other contractor.

distribution system operator (DSO)

is a natural or legal person responsible for operating, ensuring the maintenance of and, if necessary, developing the distribution network in a given area and, where applicable, its interconnections with other networks and for ensuring the long-term ability of the network to meet reasonable demands for the distribution of electricity

droop is the ratio of the steady-state change of frequency (referred to nominal frequency) to the steady-state change in power output (referred to maximum capacity) concerning frequency response

equipment electrical equipment Software and hardware intended to convert renewable energy to electrical power, to provide any GCC feature related to that or being required according to the scope. Electrical equipment can be structured in units and plants, as most of the equipment is of a distributed generation type. Electrical equipment can be e.g. power cables, power transformers, reactive power compensation installations as well as protection and control systems as far as applicable.In other words equipment as defined here is covering also any power installation as defined in /38/ see [1.5.5] with: assembled electrical equipment or electronic equipment or a combination of electric and electronic equipment in a given location and designed for coordinated operation and connected to an electricity supply system. Remark 1: The use of the installation is not specified, but it is interacting with the electricity supply system, either directly for example by means of control, regulating and protection equipment, or indirectly for example by means of measurements leading to intervention by personnel. Remark 2: Instead of “power installation” sometimes the wording “electrical installation” may be used. /38/.

electrical power system components

equipment interconnected in an electrical system able to generate / convert, collect or transform electrical power including associated measuring and protection system

electrical system within this service specification electrical systems are distribution system, transmission systems and other electrical grids intended to conduct, store, and control electrical energy in order to provide it to electrical loads owned by private, public or industrial end users as required by national laws (security of supply)

energisation operational notification (EON)

special project certificate of GCC class I for EU area called EON - is a notification issued within EU area by the RNO to a facility owner prior to switching on of its internal networkAn EON entitles the facility owner within EU area to energize its internal network by using the grid connection.

engineering procurement construction (EPC)

under an EPC contract, the contractor designs the asset, procures the necessary units etc. and builds the asset (usually a plant within a module of a facility)

equipment system or component that forms part of an assetequipment certificate see [3.3.3]evaluating party an independent party comparing results with requirementsexisting power generating module

a module which is not a new module

exhaustive requirements

GCC features fully specified by the future EU-regulation /35 (see [1.5.5]) not having the need of being nationally specified, too Opposite: Non-exhaustive requirements, see /28/ (see [1.5.5]).


Term Definition


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facility means a facility that converts primary energy into electrical energy consisting of one or more modules connected to a network at one or more connection points; term mainly used in EU area. Short form used in the text for “power generating facility”, see Figure 1-2 and Figure 1-3.

Figure 1-2 Modules and plants forming a facilityfault-ride-through FRT (fault-ride-through) means surviving any fault possible in electrical systems including

high-voltage ride-through and low-voltage ride-through final operational notification

special project certificate of GCC class I for EU area called FON - is a notification issued by the RNO to a facility owner confirming that the facility owner is entitled to operate the module by using the grid connection because compliance with the technical design and operational criteria has been demonstrated as referred to in the future EU commission regulation /35/

frequency the frequency of the electrical power system that can be measured in all network areas of the synchronous system under the assumption of a coherent value for the system in the time frame of seconds (with minor differences between different measurement locations only); its nominal value is 50 Hz or 60 Hz

frequency response See frequency controlfrequency control a typical ancillary service and more specifically the capability of a module to control speed by

adjusting the active power output in order to maintain stable system frequency (also applicable as speed control for synchronous modules) Also possible is the control of the frequency by electronic measures like power frequency converters. IEC definition is called “frequency control mode”: control of the frequency of one or more connected AC networks by varying the transmitted power. /37/Sometimes it is also called frequency response with the following similar definition.Within IEC this is called automatic voltage regulator: the capability to regulate the power output of selectable units in response to total power plant output, tie-line power flow, and power system frequency /33/. However, within this document this is called frequency response. This is a typical ancillary service and more specifically an active power frequency response requirement - this is an automatic response of active power output from units plants or modules, in response to a change in system frequency compared to the nominal system frequency. Further detail definitions are given in the Appendix of DNVGL-ST-0125 /1/, see [4.5].


Term Definition


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GCC class assessment level for grid code complianceGCC class x is defined in order to classify the level of assessment performed. Assessment levels can limit the amount of requirements as described in [3.1.3] in more detail. In short:

— GCC class I: assessment level accepted by the responsible network operator (RNO). — GCC class II: assessment level given in the service specification GCC /32/ see [1.5.5] in

[3.1.2] and the grid code applied (intersecting set of requirements). — Without GCC class: the requirements are defined individually (GCC features).

The GCC class is also distinguishing between the assessment level for types of units on the one hand (TCX), and for site specific plants (so called projects, PCX) on the other hand.

GCC features a well-defined functional performance of any electrical equipment under given operational conditions, usually intended to provide a technical function important for the security of supply or other important reasons This can be any ancillary service capability under assessment. The scope of examination is given as the GCC class. Examples for GCC features are ancillary services like frequency control. In the outdated Technical Note /36/ see [1.5.5]] GCC features have been called GCC-Parameters.

GCC services grid code compliance services provide evidence by objective means that electrical equipment fulfills specific grid code requirements, GCC features, ancillary services or corresponding capabilities as described in this service specification in combination with requirements set e.g. by electrical system operators

generation generation of electricity is a process of producing electrical energy from other forms of energy Remark to entry: The amount of electric energy produced, usually expressed in kilowatt-hours (kWh) or megawatt hours (MWh). /39/.For the use within this service specification, see below definitions for unit (power generation unit) and plant (power generation plant), both intended for the generation of electricity (see Figure 1-3).

grid code a document that sets out the procedures and requirements relating to the activities of connection, management, planning, development and maintenance of the national electrical transmission and distribution grid, as well as dispatching and metering etc.

grid code compliance GCC (grid code compliance) means the tasks related to certification, assessment and verification of technical performance capabilities required in grid codes and similar documentsSimilar documents could be laws dealing with power purchase agreements or conditions related to grid connection. Also testing, simulating and evaluating of any electrical impact on the electrical systems for distribution and transmission of electrical energy can be part of GCC.

high-voltage ride-through

now called over-voltage ride-through During faults in the electrical system voltage can rise at the output terminals of a renewable generation unit. According to the grid codes of various system operators a renewable generation plant shall stay operational during specific over voltage (UVRT, formerly called “high voltage ride through, HVRT”).

grid operator see system operator or network operatorhouse load operation in case of network failures resulting in disconnection of modules from the network and being

tripped onto their auxiliary supplies, house-load operation ensures that facilities are able to continue to supply their in-house loads

inertia a typical ancillary service not required in each case and more specifically related to the fact that a rotating rigid body such as an generator connected to a rotating mass maintains its state of uniform rotational motionIts angular momentum is unchanged, unless an external torque is applied. In the context of this ancillary service, this definition refers to the technologies for which rotating masses, their speed and the system frequency are coupled. Further detail definitions are given in the Appendix of DNVGL-ST-0125 /1/.

installation document can be a special part of a certificate of GCC class I for EU area - simple structured document (data- or tick-sheet) containing information about a type A module and confirming compliance with the relevant requirements of the future EU commission regulation /35/ The blank installation document shall be available from the RNO for the type A facility owner or alternatively the site installer on the owner’s behalf to fill in and submit to the RNO.


Term Definition


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instruction a command given orally, manually or by automatic remote control facilities, e. g. a set-point, from a network operator to a facility owner in order to perform an action

inter-array cable system

MV cables that connect the generating units one to each other and the generating plant strings to the MV switchgear installed in the substationIt is part of a module, and in most cases also part of a plant, but it could also be the lines between plants within one module or the common connection line of several plants with the single connection point of one module see (Figure 1-4).

interim operational notification (ION)

can be a special conditioned project certificate of GCC class I for EU area called ION - this is a notification issued by the RNO to a power facility owner confirming that the facility owner is entitled to operate the module by using the grid connection for a limited period of time and to undertake compliance tests to meet the technical design and operational criteria of the future EU commission regulation /35/

island operation the independent operation of a whole or a part of the network that is isolated after its disconnection from the interconnected system, having at least one module supplying power to this network and controlling the frequency and voltage

limited frequency sensitive mode (LFSM)

— over-frequency: LFSM-O

— under-frequency: LFSM-U

a typical GCC feature (LFSM-O) which means being in a module operating mode which will result in active power output reduction in response to a change in system frequency above a certain value. Further detail definitions are given in the Appendix of DNVGL-ST-0125 /1/LFSM-U the same for under frequency, power output increase below a certain value of frequency.

limited operational notification (LON)

can be a special part of a type certificate of GCC class I for EU area - is a notification issued by the RNO to a facility owner which has previously reached FON status, but is temporarily subject to either a significant modification or loss of capability which has resulted in non-compliance to the future EU commission regulation /35/ (see [1.5.5])

low-voltage ride-through

now called under-voltage ride-throughDuring faults in the electrical system voltage drops can occur at the output terminals of a renewable generation unit. According to the grid codes of various system operators a renewable generation plant shall stay operational during specific voltage drops (Under-voltage ride-through, formerly known as “Low Voltage Ride Through, LVRT”).

mandatory GCC services

when ordering a GCC service, it might be mandatory to perform some other GCC services, too, due to the case that thy are correspondingly marked as mandatory (“depending” on other services), in the Table 3-3 in [3.4]

maximum capability approach

is assessment without a GCC class, see [3.1.3] for details

maximum capacity a typical GCC-feature meaning the maximum continuous active power which a module can feed into the network as defined in the connection agreement or as agreed between the RNO and the facility ownerIt is also referred to below as Pavail and as Pmax.

minimum regulating level

a typical GCC feature meaning the minimum active power as defined in the connection agreement or as agreed between the RNO and the facility owner, that the module can regulate down to and can provide active power control. Further detail definitions are given in the Appendix of DNVGL-ST-0125 /1/

minimum stable operating level

a typical GCC feature meaning the minimum active power as defined in the connection agreement or as agreed between the RNO and the facility owner, at which the module can be operated stably for unlimited time. Further detail definitions are given in the Appendix of DNVGL-ST-0125 /1/

module short form used in the text for “power generating module”. Within EU area 3 types of modules are defined: “power park module”, “synchronous module” and “offshore power park module”. See Figure 1-2, Figure 1-3, Figure 1-4 and Figure 1-5 A module may contain one or more plants, lines and transformers, but only one single connection point (CP). With other words: for each CP there is one module only.

network electrical power grid or electrical system for collection, distribution or transmission of powernetwork code other word for grid code


Term Definition


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network operator party responsible for safe and reliable operation of a part of the electric power system in a certain area and for connection to other parts of the electric power system /43/The same as a system operator, grid operator, an entity that operates a network, these can be either a TSO, a DSO or CDSO. In case the respectively responsible network operator is referred to in the text the term “relevant network operator” is used (RNO) (i.e. the network operator in charge for the relevant equipment).

non-exhaustive requirements

such GCC features specified by the future EU commission regulation /35/ (see [1.5.5]) not completely, but only to certain extend The rest of specification is to be done by the national laws within EU, finally achieving exhaustive requirements, which are fully, defined GCC features.

over-voltage ride-through

during faults in the electrical system voltage can rise at the output terminals of a renewable generation unitAccording to the grid codes of various system operators a renewable generation plant shall stay operational during specific over voltage (UVRT, formerly called “high voltage ride through, HVRT”).

overexcitation limiter is a control device within the AVR which prevents the rotor of an directly network coupled separately excited synchronous rotating electrical machine within a generating unit from overload by limiting the excitation current This is not applicable to generating unit technologies with frequency converter between rotating electrical machine and the network.

per unit instead of percentage values, per unit does not use 100 as a reference but 1 (unit)It equals a value of percentage divided by 100.

phase 1) certification phases in the context of this service specification are three different phases: definition phase, verification phase and certification phase, see Sec.3.

2) In electrical engineering, three-phase electric power systems have at least three conductors carrying alternating current at voltages that are offset in time by one-third of the period. A three-phase system may be arranged in delta (∆) or star (Y) (also denoted as wye in some areas).

3) In the context of periodic phenomena, such as a wave, phase angle is synonymous with phase. Phase in sinusoidal functions or in waves has two different, but closely related meanings. One is the initial angle of a sinusoidal function at its origin and is sometimes called phase offset or phase difference. Another usage is the fraction of the wave cycle that has elapsed relative to the origin.

phase current measured electrical current in 2 or 3 phases


Term Definition


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plant short form used in the text for “power generating plant”, see Figure 1-2, Figure 1-4 and Figure 1-5 A module may contain one or more plants, transformers lines and other equipment but only one single connection point CP. A plant may contain one or more units.

Figure 1-3 Symbols for CP, units, plants and modulesplant control means both, control function of specific GCC features as well as the physical place where the

corresponding control functions are performed, e. g. a power plant controller according to /44/power factor is the ratio of active power to apparent power

If displacement power factor is mentioned, this is the displacement component of the power factor; ratio of the active power of the fundamental wave to the apparent power of the fundamental wave /40/.

power generating facility

see facility, short form used within the text

power generating facility owner

a natural or legal entity owning a facility according to wording within EU Short form below is facility owner This is commonly known as plant owner or generating plant owner, power house owner, wind farm owner etc. This is not necessarily the operator, which could be a different party working on behalf of the generating facility owner. The difference between plant owner and facility owner might also be further equipment other than units and plants being also connected in the same facility (see Figure 1-2).


Term Definition


DNV GL AS

power generating module

see module

power generating module document (PGMD)

can be a special certificate within EU area called PGMDThis is a document issued by the facility owner to be provided to the RNO for a type B or C module (A,B,C: the future EU commission regulation /37/ and /28/, see [?1.5.5]). The PGMD is intended to contain information confirming that the module has demonstrated compliance with the technical criteria as referred to in the future EU commission regulation /35/ see [1.5.5] and that necessary data and statements including a statement of compliance have been provided.

Power generating plant see plantPower generating unit (PGU)

see unit

power installation see equipmentpower park module (PPM)

PPM is a special module within EU area with plants built from such units, which are connected to the plant network non-synchronously or through power electronicssee “module” and Figure 1-4.

power plant see plant, short form of “power generating plant” power system stabilizer PSS - is an additional functionality of the AVR of a module, plant or unit with the purpose of

damping power oscillationsP-Q-capability diagram describes the reactive power capability of a module, plant or unit in context of varying active

power at the connection pointFurther detail definitions are given in the Appendix of DNVGL-ST-0125.

project certificate certificate for facilities, modules or plants as described in [3.3.3]project certification see [3.3.3], project verification with additional credibility due to assessment made strictly

according to certification procedures by DNV GL’s certification body Renewables Certification, being correspondingly accredited

pump-storage a hydro unit in which water can be raised by means of pumps and stored to be used later for the generation of electrical energy

reactive power reactive power Q in a single phase system is defined for steady-state and periodic signals as

where U1 and I1 are the r.m.s. values of the fundamental frequency components of the voltage and the current respectively, and j1 is the phase angle between them The reactive power in poly-phase system is the algebraic sum of the per-phase reactive powers:

where L1 and L2 are the first and second phase of the system. /41/relevant network operator (RNO)

electrical system operator in charge for the connection point or according to the connection agreement or PPA (power purchase agreement), this is the operator of the network to which a module, plant or unit is or will be connected – often responsible for a given control area

review within this service specification, review is called assessment. See assessment scope, defining assessment

The assessment scope of a GCC service can be different in each case but shall be defined in strict accordance to this service specificationIt will be defined by the GCC-class in each case. Details can be seen in [3.1.3]] (scope). Before any assessment can be performed, the scope of assessment will be defined for each customer on a case by case basis, based on the assignment procedure given in [3.1.3]. During assessment the scope and GCC class will be applied as agreed before.

second-party first-party is the person or organization that provides the object; second-party is a person or organization that has a user interest in the object.

set-point is a target value for any parameter typically related to GCC features and used in control schemes

significant module a special certificate for EU area describing a module which is deemed significant on the basis of its impact on the cross-border system performance via influence on the control area’s security of supply, which is identified according to the criteria set forth in the future EU commission regulation /35/ (see [1.5.5]) and falls within one of the categories provided in its Article 5 number 2


Term Definition


DNV GL AS

slope slope is calculated by finding the ratio of the “vertical change” to the “horizontal change” between (any) two distinct points on a line As example for GCC one of the GCC features within the ancillary service voltage control can be named. The slope in this case is defined as the ratio of the change in voltage, based on nominal voltage, to a change in reactive power fed in from zero to maximum reactive power, based on maximum reactive power.

statement of compliance

within this service specification conformity statements are called statement of compliance if they are issued by DNV GL’s certification body Renewables Certification For details see [3.3.3].

steady-state stability if the network or a module previously in the steady-state reverts to this state again following a sufficiently minor disturbance, it has steady-state stability

step there are two or three steps within one certification phase Within this service specification steps are represented by a letter, following the number of the corresponding certification phase. E. g. step 1A is in phase 1 (definition phase).

synchronous compensation operation

an ancillary service function is the operation of any equipment without providing much active power, just to regulate voltage dynamically by production or absorption of reactive power

synchronous module (SM)

a special kind of module defined within EU area as an indivisible set of installations which can generate electrical energy such that the frequency of the generated voltage, the generator speed and the frequency of network voltage are in a constant ratio and thus in synchronism /35/See Figure 1-5.This can be e. g.:

— a single unit with synchronous rotating electrical machine directly connected to the grid (“synchronous unit”), generating power within a facility directly connected to a transmission, distribution or closed distribution network, or

— an ensemble of synchronous units generating power within a facility directly connected to a transmission, distribution or closed distribution network

— with a common connection point, or— that cannot be operated independently from each other (e. g. units generating in a

combined-cycle gas turbine facility), or

— a single synchronous storage device operating in electricity generation mode directly connected to a transmission, distribution or closed distribution network, or

— an ensemble of synchronous storage devices operating in electricity generation mode directly connected to a transmission, distribution or closed distribution network with a common connection point.

synchronous power generating module

see synchronous module (SM) above

synthetic inertia is a facility provided by a power park module, plant, unit or HVDC system to replicate the effect of inertia of a synchronous module to a prescribed level of performance according to definitions within EU area /35/

system operator party responsible for safe and reliable operation of a part of the electric power system in a certain area and for connection to other parts of the electric power system /43/the same as a network operator, also: grid operator. “System operator or owner”: the entity responsible for making technical connection agreements with customers who are seeking connection of load or generation to a distribution or transmission system /42/, see [1.5].

third-party third-party is a person or body that is independent of the person or organization that provides the object (first party), and of user interests in that object (second party).

type certification type verification with additional credibility due to assessment made strictly according to certification procedures by DNV GL’s certification body Renewables Certification, being correspondingly accredited.

type certificate certificate issued by DNV GL’s certification body Renewables Certification, when it has been demonstrated that the product type in question, here a generating unit type, complies with the applicable regulations, here concerning grid codes as detailed in [3.3.3].


Term Definition


DNV GL AS

under excitation limiter a control device within the AVR, the purpose of which is to prevent the directly network connected synchronous rotating electrical machine from losing synchronism due to lack of excitationThis is not applicable to generating unit technologies with frequency converter between rotating electrical machine and the network.

Under-voltage ride-through

During faults in the electrical system voltage drops can occur at the output terminals of a unit.According to the grid codes of various system operators a plant shall stay operational during specific voltage drops (Under-voltage ride-through, UVRT, formerly known as low voltage ride through, LVRT)

unit units are defined as single generating installations This can be single wind turbines, single inverters with connected photovoltaic cells (PV) etc. converting renewable energy sources like wind speed, solar radiation or bio mass into electricity. unit is the short form for “power generating unit” (PGU). The short form is used in the text, for clarification see, Figure 1-3, Figure 1-4 and Figure 1-5 below.

Figure 1-4 Units are forming plants and modules, here: power park module


Term Definition


DNV GL AS

unit (continued) a unit may contain a transformer, one or more converters, rotating electrical machines or photovoltaic cells when forming a special module called PPM in the EU area

Figure 1-5 Typical units forming synchronous modules (SM)

Units in synchronous modules usually contain synchronous generators, turbines or combustion engines.

U-Q/Pmax-profile is a GCC feature in the form of a figure (profile) representing the reactive power capability of a module, plant or unit in context of varying voltage at the connection pointFurther detail definitions are given in the Appendix of DNVGL-ST-0125 /1/.

validation software validation against test results A validation refers to the results of a comparison between the values of voltage and electrical current calculated by simulation using a simulation model and the values measured at corresponding hardware tests of a hardware sample of exactly the same hardware which the validated simulation model is intended to represent. A simulation model is validated, if the outcome of the comparison of those values according to a given validation procedure is fulfilling all success criteria given in the validation procedure used.

verification (ISO 9000:2005): confirmation, through the provision of objective evidence, that specified requirements have been fulfilledThe term “verified” is used to designate the corresponding status. Verification can comprise activities such as:

— performing an independent review or assessment to confirm the reported results of a design analysis;

— witnessing activities such as manufacturing, testing, installation and commissioning to confirm compliance with specified procedures;

— reviewing documents to assess compliance with specified requirements;— testing/inspecting components or products to determine the compliance to applicable

specifications or technical standards.verification level see GCC-class. verification report within this service specification verification reports are called certification report if issued by

DNV GL’s certification body renewables certificationFor details see [3.3.3].A certification report may be issued by DNV GL’s certification body renewables certification as a statement to confirm the outcome of a verification process. A certification report may be issued at any stage of the verification process; it can be the final deliverable if the specified requirements to conformity statement are not fulfilled.


Term Definition


DNV GL AS

1.5.2 Acronyms and latin letters

voltage see EN 50160voltage control is a typical ancillary service requirement, usually implemented by automatic voltage regulator

(AVR)Is the continuously acting automatic equipment controlling the terminal voltage of an asset, equipment, module, plant or unit by comparing the actual terminal voltage with a reference value and controlling by appropriate means the output of an excitation system (or other measures), depending on the deviations. Further detail definitions are given in the Appendix of DNVGL-ST-0125 /1/.

wind turbine unit which converts the kinetic energy in the wind speed into electrical energy Whenever, in this service specification the term is used to describe the wind turbine in general, it describes the rotor-nacelle-assembly including all mechanical and electrical components and the support structures, as this is the unit.

Table 1-2 Table of acronyms

Acronym In fullA ampere AC alternating currentACER Agency for the Cooperation of Energy Regulators, see www.acer.europa.eu AVR automatic voltage regulatorbdew Bundesverband der Energie- und Wasserwirtschaft e.V., Germany.BIL basic insulation levelCC component certificateCDSO closed distribution system operator CHP combined heat and power in equipment intended to produce heat for heating or other needs and

electricity in the same equipment. CP connection pointCR certification reportDC direct currentDER distributed energy resources to power equipment generating electricity not in centralized power plants

but in smaller generating units clustered in generating plants as projects, again being distributed geographically to a very high extent, e.g. CHP

DSO distribution system operatorEC equipment certificateEMT electromagnetic transientENTSO-E European Network of Transmission System Operators for ElectricityEPC engineering procurement construction f frequency, Hz, see definition above under “frequency”FON final operation noteFRT fault-ride-throughFSM frequency sensitive mode GCC grid code compliance HVDC High-voltage direct currentHVRT OVRT, formerly called “high-voltage ride-through”Hz Hertz [1/s]I electrical current in A, definition above under the term „current“ION interim operational notificationIEC International Electrotechnical CommissionITT invitation to tenderLFSM-O limited frequency sensitive mode – over frequency


Term Definition


DNV GL AS

www.acer.europa.eu

LFSM-U limited frequency sensitive mode – under frequencyLON limited operational notificationLVRT UVRT, formerly known as “low-voltage ride-through”MV medium voltage level, usually between 1 and 60 kVNC RfG network code on requirements for generatorsOVRT over-voltage ride-through, formerly known as “high-voltage ride-through”OLTC on load tap changerPC project certificatePCC point of common couplingPGMD power generating module documentationPmax maximum capacityPn wind power plant nominal installed powerPPM power park module, special kind of module of plants with non-synchronous units (see Figure 1-4)pu per unit, similar like % but normalized to 1 (unit)PSS power system stabilizerPVVC PROCEDIMIENTOS DE VERIFICACIÓN, VALIDACIÓN Y CERTIFICACIÓNQoverex max maximum (over-excited) reactive power injected by the generating plant at the PCC (capacitive

operation of the generating plant)Qunderex max maximum (under-excited) reactive power absorbed by the generating plant at the PCC (inductive

operation of the generating plant)PPA power purchase agreement, connection agreement R&D Research and development is usually the department at manufacturer’s organisational chart which is

developing the implementation of GCC features in the equipment and doing corresponding research. RES renewable energy resources which can be used to power equipment generating electricity. RMS root mean squareRNO relevant network operators second [s]SDLWindV Verordnung zu Systemdienstleistungen durch WindenergieanlagenSE service specificationSIL switching impulse levelSM synchronous generating module, see Figure 1-5 and Figure 1-3: Symbols for CP, units, plants and

modulesSoC statement of complianceTC type certificateTN technical noteTR 8 (FGW) TG 8 (technical guideline) see /8/TSO transmission system operator, here: electrical systemstxt representing the need of textual description amongst values given in SI-Units like A, V etc. If the column

for SI-Units is showing “txt” it means that an additional description is necessary to fully specify the GCC feature.

UVRT under-voltage ride-through, formerly known as LVRTV Volt [V], see /34/ (see [1.5.5])var reactive power unit representation, consisting of volt and ampereW Watt [W]WTG wind turbine generator, meaning the same as wind turbineZ electrical impedance [Ω]

Table 1-2 Table of acronyms (Continued)

Acronym In full


DNV GL AS

1.5.3 Subscripts
1.5.4 Verbal forms

1.5.5 ReferencesThe services specified in this service specification refers to technical requirements and acceptance criteria for GCC as laid down in the corresponding standard GCC DNVGL-ST-0125 /1/, and in the grid codes as specified individually.

Grid code listing can be seen at http://www.dnvgl.com/GridCodeListing.pdf.

Table 1-3 Subscripts

TCx any GCC-class x for type certificate levelPCx any GCC-class x for project certificate levelPavail, Pmax maximum capacity, maximum available power PN, Pn generating plant’s nominal installed powerQoverex max maximum (over-excited) reactive power injected by the generating plant at the PCC (capacitive

operation of the generating plant).Qunderex max maximum (under-excited) reactive power absorbed by the generating plant at the PCC (inductive

operation of the generating plant)

Table 1-4 Verbal forms

Term Definitionshall verbal form used to indicate requirements strictly to be followed in order to conform to the documentshould verbal form used to indicate that among several possibilities one is recommended as particularly

suitable, without mentioning or excluding others, or that a certain course of action is preferred but not necessarily required

may verbal form used to indicate a course of action permissible within the limits of the document

/1/ “Grid code compliance”, DNVGL-ST-0125, 2015

/2/ “Project certification of wind farms according to IEC 61400-22”, DNVGL-SE-0073, 2014

/3/ “Type and component certification of wind turbines according to IEC 61400-22”, DNVGL-SE-0074, 2014

/4/ “Project certification of photovoltaic power plants”, DNVGL-SE-0078, 2015

/5/ Guidance Notes – Power Park Modules, issue 3, September 2012, National Grid, United Kingdom, available through internet at http://www2.nationalgrid.com/assets/0/745/746/3464/3466/3488/3475/08faa140-c02e-4e45-8ecb-1cf040388964.pdf

/6/ [IEV 131-11-42] according to IEC Glossary, available on internet under http://dom2.iec.ch/terms

/7/ in IEC 62443-1-1:2009 section 3.2.6, definition according to IEC Glossary, available on internet under http://dom2.iec.ch/terms

/8/ FGW TG8 Technical Guidelines for Power Generating Units, Part 8: Certification of the electrical characteristics of power generating units and systems in the medium-, high- and highest-voltage grids, Rev. 6 or newer, Fördergesellschaft Windenergie und andere Erneuerbare Energien (FGW e.V.), Germany

/9/ “CBC DECISION/CLARIFICATION SHEET” Project Certification Recognition arrangement, Sheet No. CBC 6A, 2012 http://wtcac.iecre.org/iecex/wtcac.nsf/0/CF27EFB37588275BC1257AB30047DAC8/$file/CBC-6A.pdf

/10/ bdew MV-Guideline Technical guideline generating plants connected to the medium-voltage network guideline for generating plants connection to and parallel operation with the medium-voltage network, June 2008, including all supplements, BDEW Bundesverband der Energie- und Wasserwirtschaft e.V., Germany.

/11/ Latest (this means currently valid) Version of SDLWindV is newer. There was a change in 2015:SDLWindV Verordnung zu Systemdienstleistungen durch Windenergieanlagen (SDLWindV), vom 03.07.2009, Bundesgesetzblatt Jahrgang 2009 Teil I, Nr. 39, ausgegeben zu Bonn am 10. Juli 2009, Seite 1734 (Ordinance on System Services by Wind Energy Plants /System Service Ordinance – SDLWindV/) and Verordnung zur Änderung der Systemdienstleistungsverordnung, vom 25. Juni 2010, Bundesgesetzblatt Jahrgang 2010 Teil I, Nr. 34, ausgegeben zu Bonn am 30. Juni 2010, Seite 832(Change Ordinance System Services by Wind Energy Plants)

/12/ RD661 10556, ROYAL DECRETO 661/2007, de 25 de mayo, por el que se regula la actividad de producción de energía eléctrica en régimen especial, BOE num. 126, issued 2007-05-26, page 22846, Spain (Royal ordinance for special electrical energy production scheme)


DNV GL AS

http://www.dnvgl.com/GridCodeListing.pdf

http://www2.nationalgrid.com/assets/0/745/746/3464/3466/3488/3475/08faa140-c02e-4e45-8ecb-1cf040388964.pdf

http://www2.nationalgrid.com/assets/0/745/746/3464/3466/3488/3475/08faa140-c02e-4e45-8ecb-1cf040388964.pdf

http://dom2.iec.ch/terms



http://wtcac.iecre.org/iecex/wtcac.nsf/0/CF27EFB37588275BC1257AB30047DAC8/$file/CBC-6A.pdf

/13/ PVVC “PROCEDIMIENTOS DE VERIFICACIÓN, VALIDACIÓN Y CERTIFICACIÓN DE LOS REQUISITOS DEL PO 12.3
SOBRE LA RESPUESTA DE LAS INSTALACIONES EÓLICAS ANTE HUECOS DE TENSIÓN, Versión 10, issued by AEE 2012-01-26, Spain (Verification Validation and Certification Procedure for the requirements of the PO 12.3 on the response of Wind Farms in the event of voltage dips)

/14/ IEC 61400-22: 2010 Wind turbines – Part 22: Conformity testing and certification, Edition 1.0 2010-05

/15/ Germanischer Lloyd Industrial Services GmbH, Renewables Certification „GL Rules and Guidelines - IV Industrial Services - Part 1 - Guideline for the Certification of Wind Turbines“, Edition 2010.

/16/ IEC WT01 IEC System for conformity testing and certification of wind turbines, rules and procedures, first edition 2001-04

/17/ Germanischer Lloyd Industrial Services GmbH, Renewables Certification „GL Rules and Guidelines, IV, Part 2, Guideline for the Certification of Offshore Wind Turbines“, Edition 2012

/18/ FGW TR2 Technical Guideline for Wind Turbines-Part 2: Establish power performance and standardised production (Technische Richtlinien für Windenergieanlagen – Teil 2: Bestimmung von Leistungskurve und standardisierten Energieerträgen) Fördergesellschaft Windenergie und andere Erneuerbare Energien (FGW e.V.), Germany

/19/ “Load Frequency Control of a Multi-Area Power System Using ANN Based Fuzzy Inference System”, International Electrical Engineering Journal (IEEJ) Vol. 5 (2014) No.6, pp. 1437-1443 ISSN 2078-2365

/20/ “Generic Grid Code Format for Wind Power Plants” issued on 2009-11-27 by EWEA, http://www.ewea.org/fileadmin/ewea_documents/documents/publications/091127_GGCF_Final_Draft.pdf

/21/ „GCC Grid Code Listing“, issued on a regular basis by DNV GL, http://www.gl-group.com/pdf/IGCC_list.pdf now changed to http://www.dnvgl.com/Grid CodeListing.pdf

/22/ „Technical rule for connecting wind farm to power system“, GB/T 19963, issued 2012 by China Electric Power Research Institute (CEPRI), China

/23/ „Technical rule for photovoltaic power station connected to Power Grid“, Q/GDW 617-2011, issued 2011-05-06 by State Grid Corporation of China (SGCC), China

/24/ „Test procedure of wind turbine low voltage ride through ability “, draft issued by National Energy Bureau (NEB), China

/25/ „Guideline for Modelling and Validation of Wind Turbine Low Voltage Ride Through Characteristics“, draft issued by National Energy Bureau (NEB), China

/26/ „Electric Simulation Model and Validation Method of Wind Farm“, draft issued by National Energy Bureau (NEB), China

/27/ TN 066 Technical Note (TN 066), Certification of Grid Code Compliance (GCC) Test procedure for low voltage ride through (LVRT), Rev. 8, 31.07.2013 of GL Renewables Certification.

/28/ Implementation Guideline for Network Code “Requirements for Grid Connection Applicable to all Generators”, issued 2013-10-16 by ENTSO-E

/29/ IEC 62443-1-1:2009, 3.2.6, definition according to IEC Glossary, available on internet under http://dom2.iec.ch/terms

/30/ Technical Note (TN 65) „Certification of Grid Code Compliance (GCC), Certification procedure“, Revision 8, issued 2013-07-31 by Germanischer Lloyd Industrial Services GmbH Renewables Certification, Germany

/31/ ENTSO.E definition of ancillary services, see https://www.entsoe.eu/about-entso-e/market/balancing-and-ancillary-services-markets/Pages/default.aspx

/32/ IEC 62278, ed. 1.0 (2002-09), definition according to IEC Glossary, available on internet under http://dom2.iec.ch/terms


/34/ IEC EN 50160

/35/ ENTSO-E Network Code for Requirements for Grid Connection Applicable to all Generators. Entso.E internet site for “Network Code on Requirements for Grid Connection Applicable to all Generators (RfG): https://www.entsoe.eu/major-projects/network-code-development/requirements-for-generators/Pages/default.aspx this document is going to become a European Commission regulation. A draft version can be found at https://ec.europa.eu/energy/sites/ener/files/documents/networkCodesJune.pdf

/36/ Technical Note „Certification of Grid Code Compliance”, Revision 9, issued 2014-12-04 by Germanischer Lloyd Industrial Services GmbH, GL Renewables Certification, Germany. Outdated, document replaced by this service specification.


/38/ 2.4 in IEC 62270, Communication networks and systems for power utility automation -- Part 7-410: Hydroelectric power plants - Communication for monitoring and control


DNV GL AS

http://www.ewea.org/fileadmin/ewea_documents/documents/publications/091127_GGCF_Final_Draft.pdf

https://www.entsoe.eu/about-entso-e/market/balancing-and-ancillary-services-markets/Pages/default.aspx

https://www.entsoe.eu/about-entso-e/market/balancing-and-ancillary-services-markets/Pages/default.aspx




http://www.gl-group.com/pdf/IGCC_list.pdf now changed to http://www.dnvgl.com/Grid CodeListing.pdf

http://www.ewea.org/fileadmin/ewea_documents/documents/publications/091127_GGCF_Final_Draft.pdf

/39/ IEC 60050-601, International Electrotechnical Vocabulary. Chapter 601: Generation, transmission and
distribution of electricity – General/40/ 3.3.21 in IEC 62040-3, ed. 2.0 (2011-03)

/41/ 3.1 in IEC 62053-24, ed. 1.0 (2014-06)

/42/ 3.2.1 in IEC 61000-3-13, ed. 1.0 (2008-02)

/43/ 3.1.5 in IEC 62749, ed. 1.0 (2015-04), see also IEC 60050-617:2009, 617-02-09

/44/ IEC 61400 Wind Turbines – part 27-1 Electrical simulation models, as well as future part 27-2

/45/ DIN EN ISO/IEC 17065, Conformity assessment - Requirements for bodies certifying products, processes and services (ISO/IEC 17065)


DNV GL AS

SECTION 2 PROCEDURAL REQUIREMENTS
2.1 The procedure from quotation to certification (type of unit)GCC services according to this service specification can be offered by DNV GL upon request. The definition phase [3.1] is the first and most important part for starting the procedure. Definition phase usually is performed or at least supported by DNV GL, it is recommended to start with a pre-screening according to [3.1.2].

The pre-screening can be used for GCC-class definition and corresponding scope decision. The standards, codes and requirements which form the basis for the project or type certification process shall be listed and agreed at a very early stage. Other requirements relevant for the project certification such as requirements from the local system operator and other specific requirements of the owner or the developer shall be listed. DNV GL offers to verify the GCC-class decision of the customer (see [3.1.3]). The complete procedure is described in [1.4] as overview and in Sec.3 in detail. The terms and definitions in [1.5.1] and the listing of grid codes on internet might help the customer to prepare the scope of assessment (http://www.dnvgl.com/gridcodelisting.pdf). In case of choosing no GCC-class a detailed listing of requirements is needed (see [3.1.3] and Appendix of DNVGL-ST-0125 /1/). In case of choosing GCC-class TCI or PCI corresponding relevant system operators (RNOs) have to be named and contact to them has to be prepared. For GCC-class TCII or PCII the national requirements have to be checked [2.3] and corresponding grid codes are to be named and listed by the customer.

For the time schedule of the certification the dependencies between the GCC services according to

Table 3-3 in [3.4] shall be taken into account. Testing, modelling and evaluating results shall be performed by independent parties in order to assure impartiality. Nevertheless DNV GL can provide a single point of contact coordinating the different parties being involved.

2.2 Grid code compliance services for evaluating plants or modules (site specific)The approach shall be applied for verification of a specific site related to grid code compliance of a specific power plant or module, by an independent party. The site specific approach can also be described as process of independent site suitability assessment; it is called project certification. If the GCC-class chosen is PCI, the system operator will accept the project certificate, as soon as it will be issued.

For the site specific approach the grid code requirements are fixed for the site, either by a grid code (GCC-class PCII) or by a set of GCC features (without GCC-class) similar to Table 3-2 in [3.1.3]. Site specific requirements are usually written in the contractual document for the site and the grid connection or the power purchase agreement.

The assessment in the site specific approach can be based on deliverables of the maximum capability approach or of the multi-national grid code approach. However, a type certificate in GCC-class TCII or even TCI is a better basis and reduces the effort in assessment for the plant or module significantly.

The assessment of the data will be performed according to [3.3.2].

2.3 National requirementsThe legal requirements of some countries and some grid codes prescribe the use of specific certification guidelines for certification. Certificates issued for such countries or grid codes, respectively, should therefore be based on these national requirements. This service specification is giving guidance to co-ordinate these national requirements in an international way. However, these national requirements shall be included in the approach as part of test plan preparation [3.2.2] and definition of assessment scope [3.1.3].

At the time of writing this document, legally required is certification for the following countries:

— Germany — Spain — Greece


DNV GL AS

http://www.dnvgl.com/gridcodelisting.pdf

http://www.dnvgl.com/gridcodelisting.pdf

— Portugal
— India.

These countries require certification according to the specifications in the following sub sections and the corresponding certification procedures.

Furthermore countries with related procedures are listed as well, some of the documents are additional to the legally binding grid codes, which are regularly updated and listed on internet under: www.dnvgl.com/GridCodeListing.pdf.

2.3.1 Legal requirements in the European UnionACER and ENTSO-E rules contain exhaustive and non-exhaustive requirements. Such requirements can be applied according to the Appendix of DNVGL-ST-0125 /1/ combined with the NC RfG /35/ assessment scope according to [3.1.3].

Concerning non-exhaustive requirements the following holds true: as far as national or local system operator requirements are not explicitly specifying the limitation values of such non-exhaustive requirements (GCC features) they can be assumed according to Appendix of DNV GL-ST-0125 /1/ in combination with the scope in [3.1.3].

All non-exhaustive requirements can be used as detailed e.g. in the following document by ENTSO-E:

The corresponding implementation guideline shall be used, the Guideline for Network Code: “Requirements for Grid Connection Applicable to all Generators” /28/ seems to be outdated.

For HVDC connection, the corresponding implementation guideline for the Network Code on HVDC Connections shall be taken into account.

2.3.2 Great BritainFor UK except Northern Ireland the essential document is the grid code /5/ published by National Grid. Furthermore they published a special document, focusing on type testing as well as plants (Guidance Note for Power Park developer /5/). Certification is not defined for GB but can be performed as a kind of preparation for the site acceptance test and verification procedures requested by National Grid and described in the Guideline for Power Park Modules.

2.3.3 GreeceA Greek law requires grid code compliance; see grid code No. 076 in http://www.dnvgl.com/GridCodeListing.pdf.

2.3.4 Spain and PortugalProject certification (GCC) is required according to the Spanish Royal Decree 661, RD661 /12/, see [1.5.5]. The valid certification procedure is the Spanish PVVC /13/, see [1.5.5]. Type certification (GCC) is not defined in Spain, but can be issued according to the type certification scheme of this service specification if requirements according to the Spanish PVVC /13/ are used only.

2.3.5 GermanyThe project certificate (GCC) is equal to the German “Anlagenzertifikat”, the type certificate (GCC) is equal to the German “Einheitenzertifikat” if SDLWindV /11/ or bdew MV-Guideline /10/ is used as grid code requirement. For certifications according to /10/ or /11/ the procedures and requirements according to FGW TG8 /8/ shall be applied.

2.3.6 South AfricaOn the legal basis of Electricity Regulation Act (Act 4 of 2006), the grid connection requirements and the compliance test procedures as mentioned in grid code No 118 in http://www.dnvgl.com/GridCodeListing.pdf /21/ is applicable for all types of renewable power plant technologies.


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www.dnvgl.com/GridCodeListing.pdf




2.3.7 China
There are separate grid codes for wind and PV solar equipment in China. The grid codes published for wind integration /22/ and for PV power stations /23/ can be used. In China, the various tests for grid connection and simulation model based evaluation are required. The relevant work is based on the drafted guidelines /24/, /25/ and /26/.

2.3.8 IndiaThe central government of India published grid code requirements. They have been issued in 2013 with the note, that they come into force after having been published in the Gazette of India. The Gazette of India published the document.

The grid code requirements as required for India are listed under the document No. 144 in DNV GL’s Grid Code Listing at www.dnvgl.com/GridCodeListing.pdf /21/. Proof of evidence can be provided by using the approach according to [2.3.9] applying the grid code from India or in GCC class I.

2.3.9 Multi-national grid code approach (GCC-class TCII)If a unit or any equipment shall be verified by an independent party, proving the principal ability to comply with one or more grid codes, this approach can be applied. For the multi-national grid code approach requirements in the grid codes are used as GCC features. Information in accordance to Table 2-1 shall be provided by the customer together with the order.

Assessment will be performed according to [3.3.2] (depending on the GCC-class according to [3.1.3]).

This approach can be used to receive a type certificate for one or more grid codes. This is mostly performed for units and only possible for GCC-class TCII.

2.4 Other procedural requirements

2.4.1 Validity of testsThe validity of test results intended to be used in relation with an assessment according to [3.3.2] shall be granted, this means that test results shall be qualified to be considered. If validity is not granted, test results shall not be taken as a basis for assessment.

Validity shall be verified by DNV GL. It can be regarded as granted if one of the following points is true:

— The equipment under test is identical with the equipment under assessment.— An analysis of technical equivalence and possible impact on the GCC features and capabilities has been

successfully assessed by DNV GL according to DNVGL-ST-0125 /1/. The customer has to provide corresponding documentation proving technical equivalence to be verified by DNV GL.

The quality of the test and measurement performance shall be ensured by accreditation of the test laboratory and one of the following principles:

— Testing and measurement made by DNV GL (e.g. KEMA-laboratories or DNV GL Energy advisory).

Table 2-1 Example for ordering according to Multi National Grid Code Approach

No. Author Country Title Date Revision/ Draft

007* No. according to http://www.dnvgl.com/GridCodeListing.pdf /21/



new TSO 1* country 1* new grid code 1* 2019* 0*

new DSO 1* country 1* new grid code 2* 2018* 2**: these are just examples of grid codes the applicant may order and a possible way to list grid codes


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— Witnessing of the tests by DNV GL.
— The unit under certification was tested and measured by accredited testing laboratories, accredited according to DIN EN ISO/IEC 17025 for grid code compliance.

2.4.2 Assessment according to outdated technical notes for grid code complianceAssessments of grid code compliance (GCC) previously performed according to the GL Wind Technical Notes TN065 /30/ and TN066 /27/ and TN GCC, Rev. 9 /36/ can be used, but the scope has to be adapted accordingly. Future assessments shall be performed according to this service specification and DNVGL-ST-0125 /1/. The technical note GCC /36/ is replaced by this service specification and the DNVGL-ST-0125 /1/.

2.4.3 Customer - DNV GL interactionThis document serves as a publicly available description of DNV GL’s GCC services and it will be referred to as a contractual document in the certification agreement between the customer and DNV GL. The document specifies the obligations of the customer when plants, modules, units or assets are to be certified, as well as DNV GL’s service obligations to the customer.

The deliverables to be issued by DNV GL shall be agreed in detail between the customer and DNV GL as part of the contract. In general DNV GL statements and certificates are issued when all required certification reports have been issued and the final evaluation is performed successfully.

Deliverables for assessment to be provided by the customer to DNV GL are shown in Table 3-3 (detailed listing) in [3.4], they are needed for performing the assessment. The deliverables of DNV GL for the customer are listed in Table 3-3 in [3.4], an overview can be seen in Figure 3-3 in Sec.3.

Final timeframes of the verification and certification activities shall be discussed and agreed between the customer, DNV GL, and other involved parties before commencement of the work.

2.4.4 Certification requirements, quality managementSubsequent mandatory steps shall not be initiated before previous or dependent steps or phases are completed and approved. For example, prior to verification of the unit by testing, the scope of assessment and the grid codes or other requirements used shall be defined and approved by the customer. Translations of the corresponding grid codes etc. shall be available prior to defining the scope of assessment. Therefore the geographical site area or the corresponding grid codes should be part of the ordering phase for e.g. pre-screening. Alternative ways and the related risk shall be discussed and agreed with DNV GL in advance.

If testing and measurement is not performed by DNV GL, the customer shall provide evidence of the testing and measuring laboratory showing that the laboratory is accredited according DIN EN ISO/IEC 17025 according to corresponding fields of activity.

2.4.5 Documentation requirementsThe documentation submitted for each step of the certification phases shall be complete and self-explanatory. The content shall meet the requirements based on the GCC-class decision. All relevant documentation shall be subject oriented and in a logical sequence to facilitate cross checking between documents. Each document shall be named explicitly by e.g. title, report no., page no., date and a revision description table. Furthermore the documents should be signed officially at least by the author and/or the approver to identify responsibilities. Alternatively the documentation submitted shall bear unambiguous evidence of having been subject to designer’s and/or owner’s own quality approval system.

The documentation, including standards and codes as well as other requirements and specifications, shall be prepared in the English or German language, unless otherwise agreed in writing between DNV GL and the customer.

All documentation for assessment shall be forwarded to DNV GL in electronic form, preferable as pdf-files. Other forms of documentation such as print-outs can be an alternative, if agreed.


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SECTION 3 DESCRIPTION OF GRID CODE COMPLIANCE SERVICES
3.1 Phase 1 - Definition phase

3.1.1 OverviewSee below an overview on the definition phase details in Figure 3-1, an overview about all three phases of GCC services can be seen above in [1.4].

Figure 3-1 Definition phase details

3.1.2 Grid code compliance service for pre-screening requirementsPre-screening is a technical market investigation looking at market entry barriers (e.g. existing grid code requirements) and other requirements relevant for type verification. For project verification this means investigating the locally and currently valid requirements. This can also mean investigating possibilities of site specific relaxations or cost benefit analysis for the system operator.

For specific regions or countries a pre-screening of requirements and other connection conditions can be performed and correspondingly reported by DNV GL. These reports usually involve local technical experts and represent the status known at the time of preparation.

Depending on the motivation of the customer, scope and detail can be agreed individually. This means e.g. performing investigations of markets, market entry barriers and the local currently valid requirements.


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Different scopes for reports on grid code requirements can be prepared. Depending on the target it could
be:

— for R&D combining requirements with implementation advice— for marketing combining requirements with data sheet information— for governmental or similar use in preparing locally adapted requirements.

3.1.3 Defining assessment scope for each grid code compliance serviceDefining the assessment scope is the process of GCC-class definition, finally coming to a decision about verification and assessment scope.

The certification scope and the corresponding verification scope have to be fixed for each certification. This can be either by deciding for type or project certification or other ways of verification. The different deliverables to be issued after finalization of the certification are dependent on the different verification levels.

In general the GCC services may be based on supporting advice, investigations for advising, test plan preparations, testing equipment and testing services, measurement and modelling. The GCC services include validation against test results, assessment, inspection, monitoring of implementation, certification or parts of this. An overview can be seen in [1.4].

GCC certification services can either contain the assignment of a corresponding GCC-class as defined in [3.1.3] if grid codes are used as a basis, or they can be performed without GCC-class if the scope is well defined. Such definition can be either the maximum capability approach (assessment without GCC class) according to [3.1.3] or any kind of well-defined minimum scope which should make use of the definitions listed in the Appendix of DNVGL-ST-0125 /1/. Other GCC services may also assign a corresponding GCC class if useful.

As GCC features are very specific and open a very large area of possibilities, they are classified for GCC services in four GCC classes, two for units (TCX) and two for plants (PCX):

— A GCC-class TCX (with x being I or II) means that correctly defined types of units or types of any equipment will be assessed and certified.

— A classification according to GCC-class PCX (with x being I or II) means certification of a plant or module, usually called project certification.

The decision of the customer concerning GCC-class and scope will be verified by DNV GL for plausibility. Corresponding support can be provided by DNV GL.

An overview on GCC-classes and example text of the classes can be found in Table 3-1 below. How to proceed without a GCC-class is detailed below the table.


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If no GCC-class is defined (supplier defined verification level), the verification level can be selected by the customer based on corresponding national or other requirements. Alternatively the customer may use the Appendix of DNVGL-ST-0125 /1/ to define requirements for verification. A corresponding definition shall be provided and assessed by DNV GL’s certification body renewables certification.

If verification independent from grid codes shall be carried out, the maximum capability approach can be used. This means a verification of a unit or any equipment taking into account the maximum possible capabilities of the device under assessment to be verified using definitions according to the appendix of DNVGL-ST-0125 /1/. This approach does not check compliance of a complete grid code but is giving the maximum capability of the asset instead.

Similarly it can be verified for a minimum scope, if the requirements are chosen by the customer correspondingly.

For maximum capability approach as well as for the minimum scope a set of GCC features with short codes according to the Appendix of DNVGL-ST-0125 /1/ shall be applied for certification. For that a completed data set according to Table 3-2 (including all relevant lines from Appendix of DNVGL-ST-0125) should be provided by the customer for certification together with the order. For all details see the listing in the Appendix of DNVGL-ST-0125 /1/. Please find a corresponding example as Table 3-2 below.

Table 3-1 Possible GCC classes

dev

ice GCC-class:

verification level

I

approved

II

standard

Without GCC-class

supplier defined

un

it

Exam

ple

tex

t

Cla

ss n

ota

tion type certificate

TCI

type certificateTCII

Equipment (EC) or component certificate (CC)EC, CC

The wind turbine type “Stream 120” is finally approved by system operator to be used in his grid.

The solar inverter “ConVer 12k” has been evaluated according to DNV GL’s service specification and standard and was found to fulfil the grid code requirements of Denmark, France and U.S.

The wind turbine converter “ACDC” was tested according to the maximum capability approach, reaching the values as listed and shown in the graphs of the certificate.

pla

nt

or m

od

ule

Exam

ple

tex

t

C

lass

no

tati

on

project certificate PCI

project certificatePCII

equipment (EC) or component cert. (CC) EC, CC

The wind power plant “windy island” has absolved all commissioning tests required and is approved by the system operator for generating, e.g. by FON (final operation note).

The solar PV farm “sunny site” has been evaluated according to DNV GL’s service specification and standard and was found to fulfil the local grid code requirements valid at this site.

The wind power plant “stormfront” has been evaluated against the supplier defined list of requirements (GCC features). The values are listed and shown in the graphs in the certificate. In this area there is no grid code available.


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3.2 Phase 2 – Verification phase

3.2.1 OverviewSee below an overview on the verification phase details in Figure 3-2, an overview about all three phases of GCC services can be seen above in [1.4].

Verification for units is usually done by type testing according to a test plan, verification for plants may be done by test and measurement if needed, or modules shall be made by simulations using validated simulation models of the units applied in the plant by performing simulations according to the simulation plan (see [3.2.2]).

Table 3-2 Example of Definitions without GCC Class, values to be agreed

# Requirement Description Kind of unit

Value Order

R1 see Appendix

Umax, HUmax, Cdurationreduction

Example from danish grid code

txt, V, Hz, W, s

Values to be agreed, e. g.:

UH=32 kV1 h20% reduction

yes

R5 see Appendix see separate drawing to be provided see drawing yesD1 see Appendix

AB

minimum df/dtpositiveminimum df/dtnegative

Hz/s5mHz/s5mHz/s

YesYes


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Figure 3-2 Verification phase details

3.2.2 Test plan preparationThe test plan should specify the tests and measurements prior to testing. Success criteria in accordance to the assessment scope should be defined together with test plan preparation. At the latest before starting the certification phase, success criteria shall be defined.

The test plan shall contain all testing details required for a specific certification, based on the scope of assessment, the GCC class and requirements applicable for the certification and the test procedure applied, e.g. as listed in DNVGL-St-0125 /1/. Conditions and assumptions given in the test procedures of DNVGL-St-0125 /1/ are part of any test plan prepared according to this service specification, even if these are not explicitly repeated in the specific test plan again. The same shall apply for test procedures not given in DNVGL-St-0125 /1/.

The test plan shall define the measurement channels, the minimum sampling rate per measurement channel as well as the temporal length of each data set required to satisfy the requirements of the scope of certification. If these are already defined in a relevant testing standard then this standard shall be referred to.

The test plan shall define the point of measurement. For example, the high voltage side and/or low voltage side of the unit transformer, the point of connection to the grid or the point of common coupling.


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The test plan shall define the point(s) of measurement which is (are) to be analysed and reported on in the
test report.

The general success criteria according to DNVGL-ST-0125 /1/ in [3.3.4.8] shall be taken into account as well.

In case the assessment should be based on existing test results, the validity of these results regarding the verification in question needs to be assured in a first step. Otherwise (if new tests are performed) the measurement campaign should be based on a test plan prepared by the certification body to make sure the tests are covering the desired scope. The test plan could also be prepared by the applicant and verified by DNV GL, however, this is usually linked to additional effort compared to test plan preparation by DNV GL.

In case the verification is intended to be based on simulations with validated models, a corresponding simulation plan replaces the test plan.

For project verification this task shall be performed to reveal if type tests are missing for this project verification, depending on the site specific requirements.

3.2.3 Verification testingAfter testing and measurement has been performed, stored and reported, the results need to be transferred to the evaluating party, usually the certification body. Depending on GCC-class this is usually a test report and the raw data.

Certification tests and measurements shall be performed according to the test plan. For more details about the test plan see [3.2.2]. Unit testing and measurement shall be provided by reliable test laboratories. DNV GL laboratories provide many possibilities in testing and measuring according to test plan, e.g.:

— tests and measurements in your factory or on site— under-voltage ride-through tests (on site) — high voltage testing (DNV GL’s KEMA Laboratories) — PV module testing (on site or in the lab).

All this tests and measurements can be based on the needs of manufacturers, without any evaluation of results or including some expert advisory only.

If tests and measurements shall be used for certification or other forms of verification by an independent party, it is recommended to agree on a test plan in advance, see [3.3] in DNVGL-ST-0125 /1/.

3.2.4 Modeling of simulation models and parameter adaption For units simulation models shall be prepared according to AEE PVVC, FGW TG 4 or IEC 61400-27. Other modeling rules can be accepted after consultation of DNV GL. Modelling shall be made by the manufacturer himself or a party independent of the certification body.

In case the simulation model is used for simulations within the assessment in line with the certification process, it shall generally be validated by the certification body (DNV GL renewables certification). In case generic models are used, the proper parameter adaption needs to be assured.

3.2.5 Simulation model validation against hardware testIn many cases the simulation model has to be provided for assessment including parameter listing and a description how to use it (especially in case of assessment on plant level). The simulation model shall be validated by an appropriate validation procedure.

To make sure, that settings and parameters are correctly implemented, a validation against test results shall be made by the certification body being accredited according to DIN ISO/IEC 17065 /45/. A validation against a simulation model already being validated could also be possible in specific cases but needs to be agreed individually.

Details about a validation assessment can be found in DNVGL-ST-0125 /1/. The assessment for validation shall be finalized by issuing a corresponding certification report according to [3.3.3], based on the validation according to [2.7] of DNVGL-ST-0125 /1/ and optionally by a statement of compliance for validation according to [3.3.3].


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Model data to be provided shall be according to GCC features M according to DNV GL standards’ Appendix
of DNVGL-ST-0125 /1/ and the data shall be delivered prior to model validation.

3.3 Phase 3 – Certification phase

3.3.1 OverviewSee below an overview on the certification phase details in Figure 3-3, an overview about all three phases of GCC services can be seen above in [1.4].

Figure 3-3 Certification phase details

After finalization of all verifications according to the scope defined for assessment according to [3.3.2] the final assessment and the issue of the compliance confirmations can be performed. This can be one of the documents described in [3.3.3] and [3.3.4] which are the following:

— Phase 3 step b):

Statement of Compliance (SoC) (stating compliance for separate parts of the scope (e.g. UVRT)

— Phase 3 step b): Component Certificate (CC)

— Phase 3 step b): Equipment Certificate (EC)

— Phase 3 step b): Type Certificate (TC)

— Phase 3 step b): Project Certificate (PC)

— Phase 3 step c): Compliance Monitoring ([3.3.4])


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3.3.2 Evaluating compliance
3.3.2.1 GeneralResults of the verification testing shall be evaluated by DNV GL. Also other proof of evidence may be provided by the customer and submitted to DNV GL’s certification body renewables certification for assessment. This is necessary if results of verification testing turn out to be not sufficient to fulfil requirements or in case where manufacturer declarations are required only. Usually assessment and evaluation is done by DNV GL’s certification body renewables certification. Assessments are manifold and depending on the scope defined. Deliverables after finalization are usually certification reports. Details are given in Table 3-3 in [3.4] and in DNVGL-ST-0125 /1/.

Evaluating test results or other evidences are performed in different assessment levels. Assessment has to be performed prior to certification.

Assessment levels are depending on the GCC-class. The GCC-class shall be defined according to [3.1.3] and correspondingly assigned to the assessment in each individual case. Corresponding assessment descriptions depending on the levels classified by GCC-class are given below, referencing to the DNVGL-ST-0125 /1/.

3.3.2.2 Assessment performed without GCC-class GCC services with supplier defined verification levels can be based on a minimum scope or the maximum capability approach, both independent of any grid code reference. These requirements are given as success criteria as detailed below.

Additional, optional scopes can be added individually if verified by DNV GL’s certification body Renewables Certification. This can be based on support of DNV GL advisory depending on the regions or markets the customer is aiming at to sell his products. Such marketing targets usually lead to corresponding grid codes of the relevant system operators. These can be checked e.g. by providing national pre-screening reports, giving the scope of helpful additional GCC features.

For assessment without GCC-class all procedures and requirements can be considered as given in Sec. 2 of DNVGL-ST-0125 /1/. However, this is not mandatory. GCC features or links to groups of GCC features in Appendix to DNVGL-ST-0125 /1/ can be used.

Types of units and other equipment can be assessed without GCC-class.

Projects or assets in plants or modules can also be assessed without GCC-class if requirements have been defined in the definition phase.

The customer can define a set of GCC features according to the Appendix of DNVGL-ST-0125 /1/ and assessment can e.g. show the maximum capability on plant or module level, considering the maximum capability of a single unit, depending on scope agreed in the definition phase (according to [3.1.3]).

Assumptions made in line with the unit assessment related to [2.4] in DNVGL-ST-0125 /1/ shall be re-evaluated for plants.

3.3.2.3 Assessment for GCC-classes TCII and PCII GCC-class II is based on the requirements of the grid codes specified by the customer and verified by DNV GL, limited by the scope defined in DNVGL-ST-0125 /1/ and listed below. Vice versa the standard /1/ does not extend the requirements from the grid code, so a GCC feature shall be only assessed in case the grid code asks for it. This means an assessment will be carried out for the intersecting sets of requirements, taking into account the requirements from grid codes as specified and the assessment requirements given in DNVGL-ST-0125 /1/.

For each assessment, the grid codes that are assessed are to be defined with the grid code identification name and associated date of publication as minimum (according to the Appendix, DNVGL-ST-0125 /1/). A list of applicable grid codes is available online at www.dnvgl.com/GridCodeListing.pdf /21/.

For assessment with GCC-class II all procedures and requirements shall be considered as given in Sec. 2 of DNVGL-ST-0125 /1/. This includes links to other sections or to GCC features or links to groups of GCC features in the Appendix of DNVGL-ST-0125 /1/.

Types of units and other equipment can be assessed in GCC-class TCII.


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Assessment shall include requirements (GCC features) according to the below given abbreviations (e.g. R1),
naming GCC features according to the Appendix of DNVGL-ST-0125 /1/. The relevant GCC features for this assessment are given in the bullet list below, as far as they are also required in the corresponding scope (e.g. the list of grid codes according to the contract with the customer):

— [2.2]The operational area assessment shall be performed according to [2.2] of DNVGL-ST-0125 /1/ basedon the following assessment documentation for the following GCC features

— based on manufacturer information about the following GCC features:

— R1, — R3B, R3C, — R5 including measurements according to Sec. 3 of the standard /1/.

— The following measurements shall be assessed concerning the following GCC feature:

— R5.

— [2.4]The power assessment according to [2.4] of DNVGL-ST-0125 /1/ shall be performed:

— Based on manufacturer declarations relating to measurements for GCC feature D8 the following GCC features shall be assessed with power assessment:

— D9D, D9M, D9N, D10D, D10M, D10N, D11E, D11F, D11I (all relating to D8 measurements)

— Based on measurements for the following GCC features:

— D3A, D3B, D3C, D3D, D3D, D3E, D3F, — D5A, D5B, D5C, D5D, D5E, D5F, D5G, D5H, D5I, D5J, D5K, — D6, D8 for one control scheme at minimum, — D11U

— [2.5]The assessment for behavior during faults (grid support) shall be performed according to [2.5] ofDNVGL-ST-0125 /1/

— Based on measurements for the following GCC features:

— D12 according to test plan — D12A — D12G

— [2.5.2]The assessment according to [2.5.2] of DNVGL-ST-0125 /1/ is optional.

— [2.9]The assessment concerning 50 Hz / 60 Hz shall only be performed if applicable, see [2.9] of DNVGL-ST-0125 /1/

Projects and assets forming plants modules or facilities should be assessed in GCC-class PCII.

For each assessment corresponding site data shall be given for the assessment (see Appendix of /1/, GCC features G2 to G5 and S).

Grid code requirements shall be assessed for complete facilities or modules including all plants, based on corresponding tests for the units according to Sec.3 of DNVGL-ST-0125 /1/ or corresponding type certificates. Simulations with validated models shall be performed for assessment if available.

If required by grid codes or other national rules, simulation is mandatory for GCC-class PCII.


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Site specific assessment shall be performed according to the Sections of DNVGL-ST-0125 /1/ specified in
the following as far as they are also required in the corresponding scope (e.g. the grid code valid at the site or according to the contract with the client):

— [2.2]Operational area assessment according to [2.2] of DNVGL-ST-0125 /1/ shall be applied.

— [2.3]GCC features of power quality shall be performed according to [2.3] of DNVGL-ST-0125 /1/Frequency withstand ability according to [2.3] of DNVGL-ST-0125 /1/ can only be assessed for types ofunits. For GCC-class PCII and for assessments without GCC-class it is not required to assess frequencywithstand ability, as long as a valid type certificate exists for the types of units used in the plant.

— [2.4]For power assessment [2.4] of DNVGL-ST-0125 /1/ dynamic simulations with validated simulationmodels are recommended but are required in some grid codes only. Especially power control rangeassessment shall be performed for plants according to [2.4.4] of DNVGL-ST-0125 /1/

— [2.5]Assessment of behavior during faults (grid support) shall be performed according to [2.5] of DNVGL-ST-0125 /1/ but:

— [2.5.1] of the standard UVRT can be considered fulfilled if a corresponding type certificate for the units exists and is valid.

— [2.5.2] of DNVGL-ST-0125 /1/ (OVRT) is optional.— [2.5.3] of DNVGL-ST-0125 /1/ (short circuit current contribution), shall be based on corresponding

type certificate values of the units.

— [2.8]The optional assessment of communication and control interface shall be performed according to [2.8]of DNVGL-ST-0125 /1/ if applicable.

3.3.2.4 Assessment for GCC-classes TCI and PCI Assessment in GCC-class I (e.g. TCI) is intended to be the certification procedure with the highest assessment level, the most detailed and profound assessment, delivering the highest confidence that there will be no problems in connecting units, plants or modules within the facilities when being verified with the GCC-class I.

GCC-class I is based on regional or national rules but it is also intending to achieve the acceptance of corresponding proof of evidence by the corresponding authority which in general is the relevant system operator (RNO). The RNO shall be specified when contracting, prior to start of testing. The difference between GCC-class I and GCC-class II is the involvement of the RNO in order to guarantee the corresponding acceptance. Only after the acceptance of the corresponding authority certificates according to GCC-class TCI or PCI can be issued.

For assessment with GCC-class I all procedures and requirements shall be considered as given by the RNO.

In principle assessment with GCC-class I (e.g. PCI) means a full assessment of all requirements provided by the RNO or being stated in the corresponding grid code being assigned according to [3.1.3] (scope). This assessment shall be performed without any limitation concerning the scope of assessment as described within this service specification or DNVGL-ST-0125 /1/.

As this can lead to additional testing, the test plan for GCC-class I shall be approved by the RNO or any party being in the position to grant the grid connection or to block it. Corresponding additional effort includes the preparation of the test specification, system operators approval, test and measurement performance and after that the assessment for compliance.

Due to different testing any formerly made validation of simulation models shall be verified by DNV GL’s certification body renewables certification for validity.

For the overall procedure the corresponding pre-screening report according to [3.1.2] should be used as


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starting point for the approval process with the RNO. DNV GL can support this approval process with local
staff and other expert support.

In GCC-class I the RNO shall define the scope.

Types of units can be assessed in GCC-class TCI. In this case the approval of the RNO shall be achieved by consultation or any other suitable method during the assessment. For GCC-class TCI this can be one typical RNO, or several different RNO, depending on the scope agreed upon with the customer.

The test plan shall be prepared or verified by DNV GL and accepted by the RNO. Testing results cannot be accepted for GCC-class I before the RNO has approved the test plan.

Based on the grid code requirements and the RNO’s requests, conditions for applying the assessment for future project certification in GCC-class PCI shall be recorded and included in the type certificate by DNV GL’s certification body renewables certification.

If phase-to-earth fault verification shall be performed, [3.3.4.6] of DNVGL-ST-0125 /1/ applies. This has to be clarified prior to the certification of GCC class I and shall be confirmed by the system operator then.

For projects or assets forming plants or modules the assessment can be performed in GCC-class PCI if the requirements of the RNO have been fulfilled and have correspondingly been assessed by DNV GL. Details as given in Sec. 2 of DNVGL-ST-0125 /1/ can be used.

Frequency withstand ability according to [2.5.1] of DNVGL-ST-0125 /1/ can only be assessed for types of units. For GCC-class PCI the RNO has to approve everything prior to certification.

Test plan approval by RNO might also include project specific testing.

3.3.3 Grid code compliance – certification3.3.3.1 GeneralThe typical customer for project certification is the plant developer, owner or operator or even module and facility owner or operator. Typical customers for the type certificate are unit manufacturers, designers or their sub suppliers. Other GCC services can be contracted by electrical system operators, EPC companies and the others, named before. The splitting of the GCC services in several different services offers the possibility to adjust the verification scope to the needs of the application.

3.3.3.2 Certification reportThe results of the assessment are documented in terms of certification reports. In the certification reports the unit respectively the plant or module is described. Certification reports are referenced in the statements or certificates. Also listed are the tests, which have been performed, and their parameter values and GCC features as well as the validated simulation model details.

Scope and structure of the certification reports is dependent on the GCC-class applied according to [3.1.3]. Certification reports can be issued for parts of the full scope of assessment by defining a maximum capability approach or a minimum scope according to [3.1.3] if no GCC-class is assigned.

A single certification report can be issued dealing with several subjects and scopes of assessment. The corresponding scope will be given in the certification report itself.

The GCC-class shall be stated on the cover page of each certification report, a dash, if no GCC-class has been assigned.

3.3.3.3 Statement of compliance Optional statements of compliance (SoC) can be issued for parts of assessed criteria for the scope of each certification report referenced in the statements (e.g. statement of compliance for grid support or statement of compliance for model validation).

The GCC-class shall be stated on the cover page of the statement of compliance.

3.3.3.4 Component certificateA component certificate (CC) can be issued for a component of units, plants or modules, e.g. for a specific protection device or plant controller of a plant or module. Assessment shall include its corresponding specification. It can be issued with reference to one or more grid codes if all relevant requirements of these


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grid codes have been assessed according the scope of the chosen GCC-class and if the results comply with
the requirements of the specific grid codes. On the component certificate it is mentioned if full-scale on-site tests according to [3.3.3] of DNVGL-ST-0125 /1/ have been performed.

The scope of the GCC-class is defined in [3.1.3]. The GCC-class shall be stated on the cover page of the component certificate.

3.3.3.5 Equipment certificate An equipment certificate (EC) can be issued according to the ENTSO.E NC RfG (grid code No 99 in http://www.dnvgl.com/GridCodeListing.pdf /21/) or any other guideline or standard which mentions equipment certificates.

In the EU commissions regulation the equipment certificate defines the scope of its validity at a national or other level at which a specific value is selected from the range allowed at a European level. For the purpose of replacing specific parts of the compliance process, the equipment certificate may include validated models according to [3.2.5] that have been verified against actual test results.

The equipment certificate is a document issued by DNV GL’s certification body renewables certification for equipment used in modules confirming performance with respect to the requirements of the grid code (e.g. a European Network Code) or other assessment scope as defined according to [3.1.3]. In relation to those GCC features, for which the grid code (e.g. the European Network Code /35/) defines ranges rather than definite values, the equipment certificate shall define the extent of its validity. This will identify its validity at a national or other level at which a specific value is selected from the range allowed at a European level. The equipment certificate can additionally include validated simulation models confirmed against test results for the purpose of replacing specific parts of the compliance process for Type B, C and D modules as specified in the future EU commission regulation /35/. The equipment certificate will have a unique DNV GL number allowing simple reference to it in the Installation Document or the Power Generating Module Document (PGMD).

3.3.3.6 Type certificateA type certificate (TC) can be issued for a unit, e.g. for a specific type of a unit including its type specification.

To achieve a type certificate according to this service specification successful completion of all evaluations according to [3.3.2] shall be stated by DNV GL’s certification body Renewables Certification to show compliance according to the GCC-class assigned in this case, validation according to [3.2.5] is recommended in all cases where not mandatory.

The certificate will show the GCC-class, references to one or more specific grid codes as defined by the customer within the definition phase according to [3.3], other acknowledged standards and guidelines if applied and agreed with DNV GL’s certification body Renewables Certification. On the type certificate it shall also be mentioned if full-scale on-site tests have been performed, e.g. according to Sec. 3 of DNVGL-ST-0125 /1/. The GCC-class applied shall be given on the cover page of the type certificate. Type certificates correlate with GCC-class assignments TCX (with x being I or II see also [3.1.3]).

Conditions shall be listed in the type certificate, stating under which conditions, this type certificate can be applied for project certification.

Type certificates are valid up to 5 Years, after that a re-assessment of the design and its changes, if relevant shall be considered. The scope of re-assessments depends on the changes made compared to the initial assessment and of the updated versions of the used grid codes.

3.3.3.7 Project certificate A project certificate (PC) should be issued for a plant or module, e.g. for a wind farm at a specific site having a specific grid connection point with specific values and requirements or for a GCC-class according to [3.1.3].

To obtain a project certificate, all types of units installed shall have a valid type certificate or a corresponding independent verification confirmed by certification reports referenced in the statements or certificates according to [3.3.3]). On agreement with DNV GL comparable documents from other accredited certification bodies can be recognized.


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The project certificate states compliance of the plant or module according to the applicable GCC-class with
the requirements assessed by DNV GL’s certification body renewables certification. Depending on the GCC-class applied, corresponding grid code(s) or other requirements shall be assessed for the specific site given (see [3.3.2]). Dynamic and static simulations shall prove compliance with requirements regarding all items given in DNVGL-ST-0125 /1/ as far as required by the GCC-class assigned, see [3.1.3]. Simulation according to DNVGL-ST-0125 /1/ is recommended.

The GCC-class shall be given on the cover page of the project certificate. Project certificates correlate with GCC-class assignments PCX (with x being I or II). Furthermore the following information will be shown on the project certificate:

— details about the type certificates of the units, — component certificates involved (if applicable), — corresponding references, descriptions, requirements and / or grid code(s) shall be listed on the

certificate as well as other acknowledged standards and guidelines if applied and agreed with DNV GL’s certification body renewables certification,

— Conditions under which the project certificate is valid shall be stated in the related reports.

Project certificates are valid up to 10 years, if sufficient regular inspections according to [3.3.4] and [3.5] are performed on yearly intervals. After that a re-assessment of design changes shall be considered. The scope of re-assessments depends on the changes.

If no regular inspections according to [3.5] have been performed the project certificate is valid 3 years. After that a re-assessment of design, implementation and settings should be performed.

3.3.4 Compliance monitoringOn request DNV GL can offer continuous or periodic compliance monitoring. This might be performed by issuing regular revisions of statements, certificates or in other suitable manners including inspection, if approved by DNV GL.

3.4 Service details summary and deliverables overviewThe general overview of GCC services is given in [1.4]. Below given Table 3-3 shows the corresponding details as dependencies between the different steps in terms of chronological arrangement, deliverables associated with the different steps and the main assessment documents.


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Service specification, D

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Table 3-3 Detailed GCC service listing

eliverables to DNV GL assessment)

Deliverables to the customer

(service or document)

g of markets to investigated

Pre-screening-report Technical reportGrid code listing

GCC-class decision support

C-class, GCC re listing or grid code listing

Test planSimulation plan

List of missing type tests

GCC-class, quirements it descriptionerifications

Test plan

ata for choosing st equipment

Report from accredited laboratory

Digital data from accredited laboratories as, e.g. DNV GL

KEMA laboratories

deling details ulation model

ding parameters d application descriptiont result report l measurement result data

Ste

p

Ph

ase

Description (overview in [1.4]) Dependencies on other steps

D

(for

1.a)

1 d

efin

itio

n p

has

e

Pre-screening ([3.1.2])Technical market investigation, e.g. investigate grid code requirements

in one or various given countries or specification of requirements according to customer needs based on this service specification, e.g.

market entry barriers.

NoneRecommended to start

with

Listinbe

1.b) Defining assessment scope ([3.1.3])decision about scope of assessment for certification (or / and

verification)To be performed together with the certification body.

The GCC-class shall be specified, too.

1A, pre-screening

2.a)

2 v

erif

icat

ion

ph

ase

Test plan preparation ([3.2.2])Test plan for type verification: listing of all tests and measurements needed according to the scope in order to achieve the considered

verification level.

1A, pre-screening 1B, scope

For GCC-class PCI or TCI: RNO-approved

test plan

GCfeatu

Simulation plan ([3.2.2])Simulation- and test plan for project verification: listing of tests for the site verification, if required according to the scope. Listing of missing

tests to be performed for the unit required for the site, as well as scope of simulations.

reun

v

2.b) Verification testing ([3.2.3])Test(s) and measurement(s) according to test plan in order to achieve

the proof to be used for verification. In case of plants or modules this could be missing type testing, site

specific verification measures, or simulation results based on validated simulation models.

1A, pre-screening 1B, scope

2A, test plan PCC dte

2.c) Modelling or parameter adaption ([3.2.4])Simulation model preparation for simulation of GCC features should be

prepared. Validation against tests can be part of the assessment. If generic models are used, parameter adaptions are needed.

2B, testing(modelling is

recommended to be done together with

testing)

MoSim

incluan

Tesdigita

2.d) Simulation model validation ([3.2.5])Model validation shall be performed against hardware test results.

2B, testing2C, modelling

Service specification, D

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Table 3-3 Detailed GCC service listing (continued)

iverables to DNV GL assessment)

Deliverables (service or document)

to the customer

ssessment cuments see

[3.3.2]

Certification reports (CR)

mentation to lize step 3A ssessment)

Statement of compliance (SoC)

Equipment certificate (EC)

Component certificate (CC)

Type certificate (TC)

Project certificate (PC)

mentation of changess to asset and

pport during inspection

Revision of deliverables of step 3B or 3C

Ste

p

Ph

ase

Description (overview in [1.4]) Dependencies on other steps

Del

(for

3.a)3

cer

tifi

cati

on

ph

ase

Assessment for evaluating compliance ([3.3.2])Assessment and evaluation of compliance: Measurement results and

other proof of evidence provided by the customer shall be assessed by DNV GL’s certification body renewables certification in order to perform the evaluation for grid code compliance according to scope according to

GCC-class.

1A, pre-screening1B, scope 2A, test plan2B, testing2C, modelling 2D, validation

Ado

3.b) GCC-certification ([3.3.3])Issue of certificates depending on the scope as decided in the

definition phase in step 1B

SoC (statement of compliance – ) 1A, pre-screening1B, scope 2A, test plan2B, testing2C, modelling 2C, validation3A, all CR’s issued

Docufina(aCC (component certificate)

EC (equipment certificate)

TC (type certificate)

PC (project certificate)

3.c) Compliance monitoring ([3.3.4])

Inspections and assessments, validity checks, revisions of certificates (do

changes made comply with the requirements according to GCC-class

(scope)?)

3B, certificate orformer 3C, performed before

Docu

Accessu

3.5 Inspection
The implementation of conditions stated in the reports listed in the corresponding statements or certificates of GCC-class PCI, PCII (equipment or component certificates without GCC-class or certification reports) shall be verified by DNV GL based on inspection.

The scope of inspection should be based on the conditions listed in any site specific document, e.g. in a report listed in a project certificate.

The customer, or other entity having legal responsibility on the premises where DNV GL personnel shall work, shall inform DNV GL of any safety and health hazards related to the work and/or any safety measures required for the work, prior to starting the work.

Whenever DNV GL undertakes to work on site, the customer shall provide all adequate safety measures to ensure a working environment that is safe and in accordance with all relevant legislation.


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SAF

DNV GLDriven by our purpose of safeguarding life, property and the environment, DNV GL enables organizations to advance the safety and sustainability of their business. We provide classification and technical assurance along with software and independent expert advisory services to the maritime, oil and gas, and energy industries. We also provide certification services to customers across a wide range of industries. Operating in more than 100 countries, our 16 000 professionals are dedicated to helping our customers make the world safer, smarter and greener.

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