power quality measuring, recording, compensation

7/30/2019 Power Quality Measuring, Recording, Compensation

1/30

Siemens Power Engineering Guide Transmission and Distribution 4th Edition 6/131

Introduction

For more than 100 years, electrical energyhas been a product, measured, for exam-ple, in kilowatt-hours, and its value wasdetermined by the amount of energy sup-plied. In addition, the time of day could beconsidered in the price calculation (cheapnight current, expensive peak time tariffs)and agreements could be made on themaximum and minimum power consump-tion within defined periods. The latest de-velopment shows an increased tendencyto include the aspect of voltage quality into

the purchase orders and cost calculations.Previously, the term quality was associ-ated mainly with the reliable availability ofenergy and the prevention of major devia-tions from the rated voltage. Over the lastfew years, however, the term of voltagequality has gained a completely new sig-nificance. On the one hand, devices havebecome more and more sensitive and de-pend on the adherence to certain limit val-ues in voltage, frequency and waveshape;on the other hand, these quantities are in-creasingly affected by extreme load varia-tions (e.g. in steelworks) and non-linearconsumers (electronic devices, fluorescentlamps).

Power Quality standards

The specific characteristics of supply volt-age have been defined in standards whichare used to determine the level of qualitywith reference to

s frequency

s voltage level

s waveshape

s symmetry of the three phase voltages.

These characteristics are permanently in-fluenced by accidental changes resultingfrom load variations, disturbances fromother machines and by the occurrence ofinsulation faults. In contrast to usual com-

modity trade, the quality of voltage de-pends not only on the individual supplierbut, to an even larger degree, on the cus-tomers.

The IEC series 1000 and the standardsIEEE 519 and EN 50160 describe the com-patibility level required by equipment con-nected to the network, as well as the lim-its of emissions from these devices. Thisrequires the use of suitable measuring in-struments in order to verify compliancewith the limits defined for the individualcharacteristics as laid down in the relevantstandards.If these limit values are exceeded, the pol-luter may be requested to provide for cor-rective action.

Competitive advantage thoughpower quality

In addition to the requirements stated instandards, the liberalization of the energymarkets forces the utilities to make them-selves stand out against their competitors,to offer energy at lower prices and to takecost-saving measures. These demands re-sult in the following consequences for thesupplier:

s The energy tariffs will have to reflect thequality supplied.

s Customers polluting the network withnegative effects on power quality willhave to expect higher power rates polluter-must-pay principle.

s Cost saving through network planningand distribution is different from todayspractice in network systems, which isoriented towards the customers withthe highest power requirements.

The significant aspect for the customer isthat non-satisfying quality and availability ofpower supply may cause production lossesresulting in high costs or leading to poorproduct quality.

Examples are in particular

s Semiconductor industry

s Paper industry

s Automotive industry (welding processes)

s Industries with high energy requirements

Siemens offers a wide range of productsincluding different types of recording equip-ment, as well as systems for active qualityimprovement.

Power QualityMeasuring, Recording, Compensation


2/30

Siemens Power Engineering Guide Transmission and Distribution 4th Edition6/132

Power QualityMeasuring and Recording

The SIMEAS T MeasuringTransducer

SIMEAS T is a new generation of measur-ing transducers for quantities present inelectrical power supply systems. The com-pact housings are mounted to a standardrail with the help of a snap-on mechanism.Depending on the specific application, thedevices are available with or without auxil-iary power supply or can be provided witha multi-purpose measuring transducer whichcan be configured according to individualrequirements.

Applications

s Electrical isolation and conditioningof electrical measurands for furtherprocessing.

s Industrial plants, power plants andsubstations.

s Easy-to-instal, space-saving device.

Fig. 227: Measuring transducer 7KG60, block diagram

Fig. 229: Measuring transducer 7KG60, dimensions

Digital output

Analog output 1

Analog output 2

Analog output 3

Serial interface

UH

IL1

IL2

IL3

UL2

UL3

UL1

N

Block diagram

RS 232RS 485

AC

75

90

Front view

Side view

Connection terminals

All dimensions in mm

90

105

Fig. 228: Measuring transducer 7KG60


3/30



Functions

Conversion of the measured values intoanalog or digital values suitable for systemsin the fields of automatic control, energyoptimization and operational control.

Special features

s Minimum dimensions,

s Short delivery time, standard typesdelivered ex-warehouse,

s Complies with all relevant standards,

s High-capacity output signals,

s Electrical isolation at high test voltage,

s Suitable to extend the beginning and endof the measuring range,

s Design variants for true r.m.s measure-ment.

Additional features of the multi-purposemeasuring transducers:

s Acquisition of up to 16 measurands,

s Connection to any type of single-phaseor three-phase systems, 16 2/3, 50,60 Hz,

s 3 electrically isolated outputs, 10 V and 20 mA,

s 1 binary output,

s Type of network, measurand, measuringrange, etc. can be freely programmed,

s V.28 or RS 485 serial interface for con-figuration and output of the measuredvalues.

Measurands

s AC voltage,

s AC current,

s Extension of the measuring range ispossible.

Additional features of the multi-purposemeasuring transducer:

s AC voltage and current,

s Active, reactive and apparent power,power factor, phase angle,

s System frequency,

s

Energy pulses,s Limit-value monitoring.

Special features of the parameterizablemulti-purpose measuring transducer

Input quantities

s 3 voltage inputs for 0 346 V, up to 600 Vline-to-line voltage in the three-phasesystem,

s 3 current inputs for 010 A.

Outputs

s 3 isolated outputs for 20 mA or 10 Vand smaller values,

s 1 contact, definable for error or limit indi-cation or as energy pulse,

s 1 serial interface type RS 232C (V.28) or,as an option, type RS 485 for connectionto a personal computer for configurationand data transmission.

Types of connection

s Single-phase,

s Three-wire three-phase current withconstant/balanced load,

s Three-wire three-phase current withany load,

s Four-wire three-phase current withconstant/balanced load,

s Four-wire three-phase current withany load,

s Connected either directly or via externaltransformer.

Measured and calculated quantities

s R.m.s. values of the line-to-line and starvoltages,

s R.m.s. value of the zero sequence voltage,

s R.m.s. value of the line-to-line currents,

s R.m.s. value of the zero sequence current,

s Active and reactive power of the singlephases and the sum thereof,

s Power factors of the single phases andthe sum thereof,

s Total apparent power,

s Active energy, incoming supply at thesingle phases and the sum thereof(pulses),

s Active energy, exported supply at thesingle phases and the sum thereof(pulses),

s Reactive energy, inductive, at the singlephases and the sum thereof (pulses),

s Reactive energy, capacitive, at the singlephases and the sum thereof (pulses),Line frequency.

Alarm contact

s Violation of the min./max. limits forvoltage, current, active power, reactivepower, frequency,

s Violation of the min. limit for powerfactor,

s Functional error.

Serial interface

Standard-type RS 232 C (V.28) interface forconnection to a personal computer for con-figuration, calibration and transfer of themeasured values; an RS 485-type serial in-terface is available with an additional busfunction according to IEC 60870-5-103.

Auxiliary power

Two versions: 24 to 60 V DC and 110 to250 V DC, as well as 100 to 230 V AC.

Characteristic line with breakpoint

The start and end periods of the analog

outputs can be extended according to re-quirements. This enables enlarging of thedisplay of the operating range of voltages,while the less interesting overcurrentrange can be compressed.

Configuration and adjustment

With the help of a personal computer con-nected to the serial interface, the type ofnetwork, the measurands and the outputsignals can be configured to suit the indi-vidual situation. The SIMEAS PAR softwareprogram enables easy adjustment of thedevices to different requirements. Sinceonly one type needs to be kept on stock,the user can benefit from the advantages

of reduced storage costs and easier projectplanning and ordering procedures. The soft-ware also supports and facilitates the ad-justment of the transducers.

Data output with SIMEAS T PAR

SIMEAS T PAR can also be used to contin-uously collect the data of 12 measurandsfrom the transducer and to display themboth graphically and numerically on thescreen. These data can then be saved orprinted.

Bus operation with IEC protocol

The transducer is suitable for the acquisi-tion of up to 43 measurands and for themonitoring of up to 39 measurands. Withthree analog outputs and one contact out-put only part of these data can be trans-ferred. With the help of the RS 485 serialinterface which uses the IEC 60870-5-103protocol, however, any number of meas-ured data can be transmitted to a centralunit (e.g. LSA or PC). As this protocol re-stricts the number of data units to 9 or 16measuring points, the function parametersfor file transfer can be assigned in such away as to bypass this restriction and toload any desired number of data.


4/30



SIMEAS T PAR parameterizationsoftware

Description

By means of the SIMEAS T PAR software,SIMEAS T transducers with an RS232 oran RS485 interface can be parameterizedor calibrated swiftly and easily. Measuredquantities can be displayed on the PC on-line via a graphical meter or can be record-ed and stored over a period of up to oneweek.

SIMEAS T PAR was designed for installa-tion on a commercially available PC or lap-

top with the MS-DOS operating system. Itis operated via the MS-Windows V3.1 orWindows 95 graphical user interface by PCmouse and keyboard. Operating instructionscan be created by printing the Help file.Communication with the transducer is a-chieved by means of a cable (optionallyavailable) connected via the interface thatis available on every PC or laptop. For unitsfeaturing an RS232 interface, use the con-necting cable 7KG6051-8BA or, for unitsfeaturing an RS485 interface, use the con-verter 7KG6051-8EB/EC. Three mutuallyindependent program sections can becalled up.

Parameterization

Parameterization serves to set the trans-ducer to the required measured quantities,measuring ranges and output signals etc.Users are able to parameterize the trans-ducer themselves in only a few steps.

Entry of the data in the windows providedis clear and simple, supported with Helpwindows.

Parameterization is also possible withoutthe transducer. After storage of the dataunder a separate name, the transducerscan be adjusted with the Send file com-mand. They can also be reparameterizedonline during operation.

Features

s Extremely simple and straightforwardoperation

s Storage of parameterization data undera user-defined name even without thetransducer

s Parameters are sent to transducers evenafter installation on the site

s When Receive is selected, the trans-ducers parameters are read into theParameterization window, can bemodified and can be sent back by select-ing Send

s Entered data is subjected to an exten-sive plausibility check and a messageand Help are displayed in the event ofinvalid inputs

s A parameterization list with the specificconnection diagram of the transducercan be printed

s A self-adhesive data plate can be printedand affixed to the transducer, including apossibility of entering three lines of textcontaining the name and location etc.

s When units featuring an RS485 interfaceare chosen, an additional window isavailable for entry of the bus parameters

Calibration

As the transducer features neither settingpotentiometers nor other hardware con-trols, it is calibrated easily by means of theSIMEAS T PARA software, by selection ofthe Calibrate function.

Generally, all the transducers are alreadycalibrated and factory-set when delivered.

Recalibration of the transducers is normallyonly necessary after repairs or in the eventof readjustment.

It goes without saying that the windowsand graphical characteristics displayed inthe Calibrate program can be operatedwith ease.

Here also, the test setup and explanations

of how to operate the programm are pro-vided in Help windows.

Features

s Sealed for life design

s Calibration without tools or specialdevices

s No test field environment is needed

Current inputs, voltage inputs and the indi-vidual analog outputs can be calibrated in-dependently of one another.

Fig. 230: Parameterization of the basic parameters

Fig. 232: Parameterization of an analog output

Fig. 231: Parameterization of the binary output

Fig. 233: Calibrating an analog output


5/30


Reading out data

With graphical instruments, all measuredquantities calculated in the transducer andpower quantities can be displayed onlineon a PC or laptop, and either in analogform or digitally.

To improve the resolution of the graphics,users can freely choose the number of in-struments on the screen and can freely as-sign the measured quantity and measuringrange.

These are selected and assigned independ-ently of the units analog outputs.

Displayed measured values can be stored,

printed or recorded for the EVAL evaluationsoftware.

Features

s Online measurements in the systemwith high accuracy

s The meters for the 3 analog outputswith the appropiate measuring range ap-pear automatically when the programpart is called up

s Easy addition or modification of meterswith measured quantity and measuringrange

s Selection of measured quantities inde-pendently of the analog outputs

s Storage of the layout under a file names Printing of the instantaneous values of

the displayed measured quantities

s Recording and storage of measured val-ues for the EVAL evaluation software

SIMEAS EVAL evaluation software

Description

With a PC or a notebook with the SIMEAS TPAR software installed on it, up to 25 meas-ured quantities can be displayed and re-corded online with the SIMEAS T digitaltransducer. A maximum of one week canbe recorded. Every second, one completeset of measured values is recorded withtime information. The complete recordingcan then be saved under a chosen name.

Using the SIMEAS EVAL evaluation soft-ware, the stored values can then be edit-ed, evaluated and printed in the form ofa graphic or a table (Figs. 236 to 238).

Fig. 234: Measured value display with 3 measuredquantities

Fig. 235: Measured value display with 6 measuredquantities

Fig. 236: SIMEAS EVAL, overview recorded values

Fig. 237: After setting cursors in the overview, the affiliated measurements and times are displayed in the table



6/30



Fig. 238: When a cursor is moved by the mouse,the measured values and times in the table are adapted automatically

SIMEAS EVAL is a typical Windows pro-gram, i.e. it is completely Windows-orient-ed and all functions can be operated withthe mouse or keyboard.

SIMEAS EVAL is installed together withSIMEAS T PAR and is started by doubleclicking on the EVAL icon. A window con-taining the series of measurements record-ed by SIMEAS T PAR is displayed for se-lection.

Features

s Automatic diagram marking

s Graphic or tabular representation

s Sampling frequency: 1 ss A measured value from the table can

be dragged to the graphic by simplyright-clicking it

s Add your own text to graphics

s Select measured quantities and themeasuring range

s Easy zooming with automatic adaptionof the diagram captions on the X and Yaxes

s Up to 8 cursors can be set or movedanywhere

s Tabular online display of the chosencursor positions with values and times

s Characteristics can be placed over oneanother for improved analysis

s The sequence of displayed measuredquantities can be selected and modified

s The complete recording or editedgraphic can be printed, including a possi-bility of selecting the number of curveson each sheet

s The table can be printed with measuredvalues and times pertaining to the cursorpositions.

Information for SIMEAS T ProjectPlanning

The transducer is suitable for low-voltageapplications, 400 V three-phase and 230 Vsingle-phase voltages, (max. measuring

600 L-L) and currents of 1, 5, 10 A (max.measurement 12 Ar.m.s), either directly orvia current transformers, as well as forconnection to voltage transformers of

10003, 110

3, 200

3. The devices can

be pre-configured at the factory accordingto customer requirements or configurationcan be performed by the customer himself.The latter possibility facilitates and consid-erably reduces the customers expense for

storage and spare parts service. All usualvariants of connection (two, three or four-wire systems, constant/balanced or any/unbalanced load 16 2/3, 50, 60 Hz) can beconfigured according to individual require-ments.

Please note that two different types areavailable which differ in their types of inter-face: V.28 (RS 232C) and RS 458. The stand-ard interface (V.28) is used for configuration.It enables loading of the measured valuesto a personal computer, whereby only onetransducer can be connected to a com-puter. Both versions are operated withthe SIMEAS PAR software. The RS 485enables connection to a bus, i.e. up to

31 transducers can be connected to a cen-tral device (e.g. PC) simultaneously. Datatransmission is based on IEC 60870-5-103protocol.

The type of power supply is to be speci-fied when ordering, either 24..60 V DC or100..230 V AC/DC. Please note that analogoutput 1 and the serial interface use thesame potential and can be operated simul-taneously only under certain conditions.


7/30



162.2 (6.39")

86 (3.39")

96 (3.78")

96 (3.78")

SIMEAS P

SIMEAS P

Side view

Front view

Fig. 239: Power Meter SIMEAS P, views and dimensions

Power Meter SIMEAS P

The SIMEAS P power meter is suitable forpanel mounting. The digital multi-functiondisplay can replace any measuring devicesusually required for a three-phase feeder.Furthermore, it offers a variety of addition-al functions. The optional equipment with aPROFIBUS enables centralized access tothe measured values.

Application

All systems used for the generation anddistribution of electrical power. The device

can be easily installed for stationary use.

Functions

Measuring instrument for all relevantmeasurands of a feeder. Combination ofseveral measuring instruments in one unit.

Special features

Dimensions for panel mounting accordingto DIN (front frame 96 x 96 mm). IntegratedPROFIBUS as optional equipment. Dataoutput is effected via the Profibus.

Measuring inputs

s 3 voltage inputs up to 347 V (L-E), 600 V(L-L),

s 3 current inputs for 5 A rated current,measuring range up to 10 A with anoverload of 25%.

Communication

s LCD display with background illumina-tion,

s Simultaneous display of four measuringvalues,

s Parameter assignment by using the keyson the front panel,

s 1 serial interface type RS 485 for con-nection to the Profibus (option).


8/30



Auxiliary power

Two versions: 24 to 60 V DC and 85 to240 V AC/DC.


s R.m.s. values of the line-to-ground orline-to-line voltages and the mean value,

s R.m.s. values of the line-to-line currentsand the mean value,

s Line frequency,

s Power factor (incl. sign),

s Active, reactive and apparent power,separately for each phase and as awhole, imported supply,

s Total harmonic distortion (THD) for volt-age and currents, separately for eachphase, up to the 15th harmonic order,

s Unbalanced voltage and current,Active and reactive power (import,export), total sum, difference,

s Apparent power, total sum,

s Minimum and maximum values of mostquantities.

Basic Function

Display of the measured quantities andtransfer to the Profibus.

Information for Project Planning

The SIMEAS P can be delivered in differ-ent designs varying with regard to themeasuring voltage, auxiliary voltage, linefrequency and type of terminals. It is alwaysdesigned for four-wire connection at anyload. The measuring voltages are:

s 120 V, 277 V, 347 V L-N for screwclamps, up to max. 277 V for self-clamping contacts.

s The basic rated current value is 5 A;fully controlled it is 10 A.

Two variants are to be considered forthe auxiliary voltage: standard versionand 85240 V AC/DC and, as an option2060 V DC.

The standard version of the device can beused only for the display of the differentmeasurands. Communication with a cen-tralized system is possible only in connec-tion with the Profibus which can be or-dered as optional equipment.

Fig. 240: Power Meter SIMEAS P, back panel diagram

N L + G Captured-wireterminals

Barrier-typeterminals

(ring or spadeconnectors)

Thumbscrew

Chassis groundAWG 14(2.5 mm)

PROFIBUSDE

PWR

VVVV

Fuses 2 Amp

Power supply connections,phase voltage and currentconnections, and fuse,CT and PT details dependon the configuration of thepower system.

Phase voltage andpower supply connections:AWG 12 to AWG 14(2.5 mm to 4.0 mm)

SHORTING BLOCK or TEST BLOCK

SIMEAS P


9/30



Communication

s 2 optorelays as signaling output, availa-ble either for

device in operation, energy pulse, signaling the direction of energy flow

(import, export), value below min. limit for cos , pulse indicating a voltage dip,

s 3 LEDs indicating the operating statusand PROFIBUS activity,

s 1 RS 485 serial interface for connectionto the PROFIBUS.

Auxiliary power

Two versions: 24 to 60 V DC and 110 to250 V DC, as well as 100 to 230 V AC.


s R.m.s. values of the line-to-ground orline-to-line voltages,

s R.m.s. values of the line-to-line currents,

s Line frequency (from the first voltageinput),

s Active, reactive and apparent power,separately for each phase and as awhole,

s Harmonics for voltages and currents upto the 40th order,

s Total harmonic distortion (THD), voltagesand currents of each phase,

s Unbalanced voltage and current in thethree-phase system,

s Flicker irritability factor.

Averaging intervals

s Voltages and currents from 10 ms to60 min.,

s Other quantities from 1s to 60 min.

The SIMEAS Q Quality Recorder

SIMEAS Q is a measuring and recordingdevice which enables monitoring of allcharacteristics related to the voltage quali-ty in three-phase systems according tothe specifications defined in the standardsEN 50160 and IEC 61000. It is mounted ona standard rail with the help of a snap-onmechanism.

Application

Medium and low-voltage systems.The device requires only little space and

can be easily installed for stationary use.

Functions

Instrument for network quality measure-ment. All relevant measurands and operandsare continuously recorded at freely defina-ble intervals or, if a limit value is violated,the values are averaged. This enables theregistration of all characteristics of voltagequality according to the relevant standards.The measured values can be automaticallytransferred to a central computer systemat freely definable intervals via a standard-ized PROFIBUS DP interface and at atransmission rate of up to 1.5 Mbit/s.

Special featuress Cost-effective solution.

s Comprehensive measuring functionswhich can also be used in the field ofautomatic control engineering.

s Minimum dimensions.

s Integrated PROFIBUS DP.

s The integrated clock can be synchro-nized via the PROFIBUS. Configurationand data output via PROFIBUS DP.

Measuring inputs

3 voltage inputs, 0 280 V,3 current inputs, 0 6 A.

Fig. 241: The SIMEAS Q quality recorder

Front view

Side view

Connection terminals

Terminal block

All dimensions in mm

SIMEAS Q7KG-8000-8AB/BB

PROFIBUS-DPPROFIBUS-DP Aux. Volt.

1 2 3 4 5 6 7 8 9 10

Input: Current AC Input : Vo lt . AC

20 21 22 23 24 25

UL1 UL2 UL3IL3IL3IL2IL2IL1IL1 ULN

90

105

75

90

SIMEAS Q7KG-8000-8AB/BB

PROFIBUS-DPPROFIBUS-DP 20 21 22 23 24 25

RUN BF DIA

1 2 3 4 5 6 7 8 9 10

Fig. 242: The SIMEAS Q quality recorder,dimension drawings


10/30


11/30



Fig. 244: SIMEAS N Quality Recorder

The SIMEAS N Quality Recorder

SIMEAS N is a measuring and recordingdevice which is used to monitor all charac-teristics referring to the voltage quality inthree-phase systems in compliance withthe requirements stated in the EN 50160and IEC 1000 Standards.

Application

Medium and low-voltage systems, laborato-ries, test bays. Portable device for mobile use.

Functions

Device for network quality measurement.The measurands and operands are continu-ously recorded over definable intervals; incase of limit violations, the values will beaveraged. This enables the recording of allcharacteristics relevant to voltage quality.In addition, this multi-purpose device canbe used for general measurement tasks inthe field of AC power engineering.

Special features

Comprehensive measuring functions. A lock-able cover protects the terminals againstaccidental contact. The operator access canbe password-protected. Clamp-on probeswith an error correction function facilitate

connection. A back-up battery stores themeasured data in case of voltage failure.The integrated battery-backed real-time clockwill be usable until the year 2097.

Output of the measured values via inte-grated thermal printer, floppy disk or serialinterface.

Measuring inputs

s 4 voltage inputs, 0460 V,

s 3 of these inputs with additional transientacquisition 2650 Vpeak at a samplingrate of 2 MHz,

s 4 voltage/current inputs, voltage0460 V/clamp-on probe or transducer.

Communication

s 1 input for trigger signal,

s 1 contact as alarm output,

s 1 integrated thermal printer,

s 1 3.5" floppy disk drive, 1.44 MB forparameters and data storage,

s 1 serial interface type RS 232C (V.24) forconnection to a personal computer forconfiguration and data transmission.


s R.m.s. values of voltages, AC, AC+DC,DC,

s Peak voltage values during transient

measurement,

s R.m.s values of currents, AC, AC+DC,DC (depending on transducer or clamp-on probes),

s Voltage dips and voltage cutoffs,

s Overvoltages,

s System frequency,

s Active, reactive and apparent power,1- to 3 phases,

s Phase angle,

s Harmonics of voltages and currents upto the 50th order,

s Total harmonic distortion (THD), voltagesand currents, unweighted or weightedinductively or capacitively,

s Unbalanced voltage and current in thethree-phase system.

Connection types

s Single phase,

s Four-wire three-phase current.

Measurands and operands,available as an option

s Direction of harmonics,

s Flicker measurement,

s Digital storage oscilloscope.

Operating modes

s Continuous measurement with displayat one-second intervals,

s Continuous measurement with data stor-age,

s Event-controlled measurement with datastorage.

Storage capacity

Up to 500,000 measured and calculatedvalues; various options for defining themeasuring points.

Function

Continuous measurement without storageroughly corresponds to the function of amultimeter. The selected values to bemeasured are continuously displayed andthe whole screen content including thegraphic illustrations can be printed on theintegrated thermal printer by key command.This operating mode is used to check cor-rect connection of the device and is suitablefor general measurement tasks. Monitoringof the network quality is effected by contin-uously calculating and storing the mean val-ues of the measured quantities. In the stor-age mode, the averaging interval can beconfigured individually from one period ofthe system voltage up to several months.Two types of storage modes can be select-ed, either linear mode (stops when thememory is full) or overwrite mode (the old-est data will be overwritten by the new in-formation).

With the help of the OSCOP Q program, themeasuring data can be transmitted toa personal computer for detailed analysis.


The basic version of the device is fullycapable of simultaneous acquisition of up to55 measurands.

The voltage range of 400 V +15% is suita-ble for connection to 400 V three-phase sys-tems. Clamp-on probes (10, 100 and 1000A) for current measurement are available.The connection of a transducer is possible,if a resistor provides a voltage drop of 1 Vnominal value.

The device can also be delivered for high-speed processing which enables simultane-ous acquisition of up to 186 different meas-urands.

Optional functions which can be added at alater date by software installation:

s Power measurement of individual har-monics and their direction in order to

identify the cause.s Extension of the device functions for use

as an additional three-channel digital oscil-loscope.

s Flicker measurement according toIEC 60868.


12/30



Fig. 247: Fault record

Fig. 246: and to monitor transmission lines

Fig. 245: SIMEAS R Systems

are used in power plants

Recording Equipment

The SIMEAS R Fault and Digital Recorder

Application

s Stand-alone stationary recorder for extra-high, high and medium-voltage systems.

s Component of secondary equipment ofpower stations and substations or indus-trial plants.

Functions

Fault recorder, digital recorder, frequency/power fault recorder, power quality record-er, event recorder.

All functions can be performed simultane-ously and are combined in one unit with noneed for additional devices to carry out thedifferent tasks.

Special features

s The modular design enables the realiza-tion of different variants starting fromsystems with 8 analog and 16 binary in-puts up to the acquisition of data fromany number of analog and binary chan-nels.

s Clock with time synchronization usingGPS or DCF77.

s Data output via postscript printer, re-mote data transmission with a modemvia the telephone line, connection toLAN and WAN.

Fault Recording (DFR)

This function is used for the continuousmonitoring of the AC voltages and cur-rents, binary signals and direct voltages orcurrents with a high time resolution. If afault event, e.g. a short-circuit, occurs, thespecific fault will be registered includingits history. The recorded data are then ar-chived and can either be printed directly inthe form of graphics or be transferred to adiagnosis system which can, for example,be used to identify the fault location.

Fault detection is effected with the help oftrigger functions. With analog quantitiesthis refers to

s exceeding the limit values for voltage,current and unbalanced load (positive

and negative phase sequence system).s falling below the limit values for voltage,

current and unbalanced load (positiveand negative phase sequence system).

s limit values for sudden changes in up ordownward direction.

Monitoring of the binary signals includes

s signal status (high, low)

s status changes


13/30



Logical triggers

Logical triggers can be defined by combin-ing any types of trigger event (analog orbinary). They are used to avoid undesiredrecording by increasing the selectivity ofthe trigger function. The device can distin-guish between different causes of a fault,e.g. between a voltage dip caused by ashort-circuit (low voltage, high current)which needs to be recorded, and the dis-connection of a feeder (voltage low, cur-rent low) which does not need to be re-corded.

Sequential control

An intelligent logic operation is used tomake sure that each record refers to theactual duration of the fault event. This is toprevent continuous violation of a limit value(e.g. undervoltage) from causing perma-nent recording and blocking of the device.

Analog measurands

16-bit resolution for voltages and DC quan-tities and 2 x 16-bit resolution for AC volt-ages.The sampling frequency is 256 times theperiod length, i.e. 12.8 kHz at 50 Hz and15.36 kHz at 60 Hz for each channel.

A new current transformer concept ena-

bles a measuring range between 0.5 mAand 400 A r.m.s. with tolerances of


14/30



The individual diagrams can, of course, beadjusted to individual requirements withthe help of variable scaling and zoom func-tions. Records from different devices canbe combined in one diagram. The differentquantities measured can be immediatelycalculated by marking a specific point in adiagram with the cursor (impedance, reac-tance, active and reactive power, harmon-ics, peak value, r.m.s. value, symmetry, etc.).

Additional diagnosis modules can be usedto perform an automatic analysis of faultevents and to identify the fault location.The program also supports server/clientstructures.

Configuration Evaluation

WANISDNX.25

Telephone

OfficeLAN

ContainerizedData Base

Spontaneousprint

Spontaneousprint

RMS values+ diagnostic

Data compression

Diagnostic system

Decentralized Data Base

Remote control, automatic mode

StationsLAN

SIMEAS R8 analog/16 binary inputs

Evaluation

Configuration

Printer

DAKON

Load Dispatch Center

Station Level

Bay Level

Office

The OSCOP P Evaluation Program

The OSCOP P software package is suitablefor use in personal computers provided withthe operating systems MS WINDOWS 95/98or WINDOWS NT. It is used for remotetransmission, evaluation and archiving (da-tabase system) of the data received froma SIMEAS R or OSCILLOSTORE and fromdigital protection devices. The programincludes a parameterization function forremote configuration of SIMEAS R andOSCILLOSTORE units.

The program enables fully-automated datatransmission of all recorded events from

the acquisition units to one or more evalua-tion stations via dedicated line, switchedline or a network; the received data canthen be immediately displayed on a moni-tor and/or printed (Fig. 249).

The OSCOP P program is provided witha very convenient graphical evaluation pro-gram for the creation of a time diagramwith the curve profiles, diagrams of ther.m.s. values or vector diagrams (Fig. 252).

Fig. 249: Example of a distributed recording system realized with SIMEAS R recorders and data central unit DAKON

Information for Project Planningwith SIMEAS R

The secondary components of high ormedium-voltage systems can either beaccommodated in a central relay room orin the feeder dedicated low-voltage com-partments of switchgear panels. For thisreason, the SIMEAS R system has beendesigned in such a way as to allow bothcentralized or decentralized installation.

The acquisition unit can be delivered intwo different widths, either 1/2 19" or 19"(full width). The first version is favorableif measurands of only one feeder are to be

considered (8 analog and 16 binary signals).This often applies to high-voltage plantswhere each feeder is provided with an ex-tra relay kiosk for the secondary equipment.In all other cases, the full-width version of19" is more economical, since it enables theprocessing of up to 32 analog and 64 bina-ry signals. The modular structure with avariety of interface modules (DAUs) providesa maximum of flexibility. The number ofDAUs which can be integrated in the ac-quisition system is unlimited.


15/30


MeasurandsDAU Type

4 AC voltages,4 AC currents,16 binary signals

8 AC voltages,16 binary signals

8 AC currents,16 binary signals

8 DC currents or16 binary signals

16 binary signals

Use of the interface modules

VCDAU

VDAU

CDAU

DDAU

BDAU

Application

Monitoring of voltages and currents ofthree-phase feeders or transformers includingthe signals from protective equipment.All recorder functions can be run simultaneously.

Monitoring of busbar voltages

Monitoring of feeder and transformer currentsor currents at the infeeds and couplings of busbars

For monitoring of quantities received frommeasuring transducers and telecontrol units,20 mA or 1 and 10 V.

Event recording of alarm signals, disconnectorstatus signals, circuit-breaker monitoring


Fig. 251: Use of the data acquisition units

Fig. 252: OSCOP P Program, evaluation of a fault record

Fig. 250: Rear view of a SIMEAS R unit with terminalsfor the signals and interfaces for data transmission

With the help of a DAKON, several devicescan be interlinked and automatically con-trolled. In addition, digital protection devic-es of different make can be connected tothe DAKON.

The voltage inputs are designed for directconnection to low-voltage networks or tolow-voltage transformers. Current inputsare suitable for direct connection to currenttransformers (IN = 1 or 5 A). All inputscomply with the relevant requirements forprotection devices acc. to IEC 60255.The binary inputs are connected to floatingcontacts.

Data transmission is preferably effectedvia telephone network or WAN (Wide AreaNetwork). If more than one SIMEAS R isinstalled, we recommend the use of aDAKON (data concentrator). The DAKONcreates connection with the OSCOP Pevaluation program, e.g. via the telephonenetwork. Moreover, the DAKON automati-cally collects all information registered bythe devices connected and stores thesedata on a decentralized basis, e.g. in thesubstation. The DAKON performs a greatvariety of different functions, e.g. it sup-ports the automatic fax transmission ofthe data. A database management systemdistributes the recorded data to differentstations either automatically or on special

command.


16/30


Compensation Introduction Power Quality

Compensations Systems

Many consumers of electrical energy (trans-formers, engines, fluorescent lamps) maycause a number of different problems:reactive displacement power, non-linearloads (rectifiers, transformers), resulting indistorted waveshapes. Harmonics are gen-erated and, finally, an unbalanced load atthe three phases leads to increased appar-ent power and thus to increased powerconsumption. This is accompanied by high-er conduction losses, which require theinstallation of lines and operating equipment

suitable for higher capacities and at highercosts than actually necessary. The cost forpower rates in relation to the apparent pow-er and distortion should also be considered.In many cases it is favorable to performcompensation of the undesired components.

Siemens offers two different systems forthe compensation of reactive power and ofharmonics SIPCON T and SIPCON DVR/DSTATCOM both suitable for three-phaseLV systems up to a rated voltage of 690 V.The latter system is available in designsalso capable of compensating short-termvoltage dips and surges, as well as loadunbalances.

s SIPCON T

Passive systems using switchedcapacitors or capacitors with permanentwiring.

s SIPCON DVR / DSTATCOMActive systems using IGBT convertersfor quick and continuous operation.

The use of SIPCON can enable energysuppliers worldwide to provide the endconsumer with distinctive quality of supply.As it is now possible with this technologyto supply Premium Energy, an energysupplier can formulate differing tariffs forhis product electrical energy so that hewill stand out from his competitors.

30.00

25.00

20.00

15.00

10.00

5.00

0.0010 ms

to 100 ms100 ms

to 500 ms500 ms

to 1 s1 s

to 3 s20 s

to 60 s3 s

to 20 s

interruption 10060 to 100

30 to 6010 to 30

Duration of voltage dips

Magnitudeof voltagedip [%]

Frequency ofvoltage dips [%]

Fig. 253: Frequency and duration of voltage dips

Fig. 254: Active compensation system(Power Conditioner DSTATCOM)

For industry, especially in the case of com-plex manufacturing processes (such as forexample in the semiconductor industry)Premium Energy is an absolute necessity.SIPCON is capable of effectively suppress-ing system perturbation, such as for exam-ple harmonics. Here as well, tariff changesare to be expected worldwide in the fu-ture. Investigations in Europe have shownthat the increase in harmonics is imposinga particular strain on systems. Such har-monics occur through the operation of vari-able speed drives, of rectifiers for exam-ple in electroplating and of inductionfurnaces or wind power plants. In private

houses, the principal loads are single-phase, such as TV sets and personal com-puters. With the aid of selective recordingof weaknesses in the electrical system andsubsequent use of the SIPCON PowerConditioner, it will be possible to improvesystem loading and to significantly rational-ize the high capital investment necessaryfor system expansion.


17/30


MMM

Group correction

M M

MMM

M

Centralized correction

Controller

Fig. 256: Group correction

Fig. 257: Centralized correction

Fig. 255: Individual correction

M

Individual correction

Power QualityPassive Compensation Power Factor Correction

The SIPCON T Passive Filtersand Compensation Systems

All consumers based on an electromagnet-ic operation principle (e.g. motors, trans-formers, fluorescent lamps with series re-actors) require a lagging reactive power.This leads to an increase in the amount ofapparent power and consequently in current.The supply of reactive power from the mainsleads to additional load applied to the oper-ating equipment which, as a result, needsto be configured for higher capacities thanactually required. The higher current is ac-companied by an increased power loss.However, the required reactive power canalso be generated close to the consumerwith the help of capacitors which preventthe above mentioned disadvantages. Whenselecting the capacity it is general practiceto calculate with a power factor of 0.9 orhigher.Compensation can be effected according tothree different principles: individual correc-tion, group correction and centralized cor-rection.

Individual Correction

This type of compensation is reasonablefor consumers with high capacities,

constant load and long operating times.(Fig. 255).

s The capacitor is installed close to the op-erating equipment. The lower currentflows already in the line from the busbarto the consumer.

s The capacitor and the consumer areturned on and off together; an additionalswitch is not required.

When selecting the type of capacitorsplease note that in the case of inductionmotors, the reactive power supplied by thecapacitor must not exceed approx. 90% ofthe motor reactive power in idle operation.Otherwise, disconnection might cause self-

excitation by the resonance frequency,since the motor and the capacitor form aresonant circuit. This effect may lead tohigh overvoltages at the terminals and af-fect the insulation of the operating equip-ment. As a general rule, the following val-ues should be considered for the capacitor:

s Approx. 35% of the motor powerat 40 kW,

s Approx. 40% of the motor power from20 to 39 kW,

s Approx. 50% of the motor powerat < 20 kW.

Under unfavorable conditions, adherenceto this rule may lead to a power factorsmaller than 0.9. In this case, centralizedcorrection should be performed additionally.

Group Correction

A group of consumers, e.g. motors or fluo-rescent lamps, operated by one commonswitch, can be compensated with one sin-gle capacitor (Fig. 256).

Centralized Correction

The solution for correcting the power fac-tor for a great number of small consumerswith varying power consumption is a cen-tralized compensation principle (Fig. 257)using switched capacitor modules and acontroller. The low losses of the capacitorsallows them to be integrated directly in theswitchboards or distributors.

A programmable controller is used to mon-itor the power factor and to switch the ca-pacitors according to the reactive-powerflow.

The devices for group correction differ intheir power and in their number of switch-ing steps. For example, a unit with 250 kVAcan be switched in steps of 50 kVA.We recommend the use of units suitablefor switching between five and twelve

steps.


18/30


Fig. 258: SIMEAS C Power Factor Controller

Active power Pa 550 kW

Power factor cos1 0.6Apparent power S1 920 kVA

Current I1 1330 A

cos1

S1

=Pa

Two examples

Uncompensated system, rated voltage 400 V

Compensated system, rated voltage 400 V

3 UI1 =

S1

3 400 V=

920 kVA= 1330 A

0.6=

550 kW= 920 kVA

Power factor cos2 0.9Capacitor power QC 470 kvar

Apparent power S2 610 kVA

Current I2 880 A

cos2S2 =

Pa

3 UI2 =

S2

3 400 V=

610 kVA= 880 A

=550 kW

= 610 kVA

QC= Pa (tan1 tan2)

The correction of the power factor fromcos1 = 0.6 to cos2 = 0.9, results in a34% reduction in apparent power trans-mitted. Line losses can be reduced by56%.

S1

S1 S2 = 0.34

I12

I12

I22

= 0.56

1

2

0.9

Q2

1

2

QC

Q1

S1

S2

P

Fig. 259: Effect of compensation

Fig. 260: Examples of power factor control

Power QualityPassive Compensation Power Factor Control

The SIMEAS C Power FactorController

The centralized correction principle is ef-fected with the help of a controller. Thisunit is designed for panel mounting (frontframe dimensions 144 x 144 mm accord-ing to DIN) in the door of the compensa-tion equipment. It is connected to L1, L2and L3 of the mains voltage; the current istaken from a current transformer in L1 rated1 A or 5 A.

All capacitor modules connected are

switched stepwise in such a way as toenable best approximation to the setpointvalue of the power factor. Defined waitingperiods prevent excessive switching opera-tions and ensure that the capacitor will bedischarged properly before the next con-nection. Two setpoints (cos 1 and cos 2)can be specified separately to enable dif-ferent modes for day and night time.

Each capacitor module is operated by con-tactors which are controlled by means ofsix contacts. A further contact is used forerror indication. One input for a floatingcontact is used to select one of the twosetpoints for the power factor. Apart fromthe control function, the device also offers

a great amount of information on the sta-tus of the supply system. It shows:

s Setpoint cos 1,s Setpoint cos 2 (e.g. night operation),s Line current,

s Voltages,

s Active power in kW,

s Apparent power in kVA,

s Actual reactive power in kvar,

s Deviation of the reactive power fromthe setpoint value,

s Reactive power of the activatedcapacitors,

s Harmonics of voltage U5,



s Harmonics of current U5,

s Harmonics of current U7,

s Harmonics of current U11.

A fiber-optic interface is accessible at therear of the device. On request, a cablesuitable for the conversion of optical puls-es into RS 232C (V.2) signals can be sup-plied. This cable enables connection to apersonal computer which can be used toprogram the controller and to read out pa-rameters, as well as the measured values.


19/30


Ripple controlfrequencies

< 250 Hz

> 250 Hz

> 350 Hz

Reactor/capacitorratio p

14%

7%

5%Q

C= Pa(tan1 tan2)

Er

= reactive energy (kvarh)

Ea = active energy (kWh)t = operating time in hours over

the accounting period

tan2= calculated from the setpointvalue for cos2

tQC =

Er (Ea tan2)

Fig. 261

Fig. 262

Fig. 263: Types of compensation for different ripplecontrol frequencies

Power QualityPassive Compensation Power Factor Control

Selecting the Capacitor Power

When defining the capacitor power for asystem, the active power P and the powerfactor cos 1 of the system have to beconsidered. In order to upgrade cos 1 tocos 2, the following applies to the powerQC of the capacitor:

The diagram in Fig. 259 shows how theapparent power S1 caused by activepower Pa and reactive power Q1 is re-duced to the value S2 by the capacitorpower QC. When taking into account thatthe current is proportional to the apparentpower, whereby the loss caused by thecurrent increases by the power of two, thesaving is remarkable. This result is possiblysupported by a lower energy tariff to bepaid.

With systems in the planning stage we canassume that the reactive load is causedmainly by induction motors. These motorsoperate with an average power factor of

0.7. Increasing the power factor to 0.9requires a capacitor power of approx. 50%of the active power.

In present industrial plants, the requiredcapacitor power can be determined on thebasis of the energy bill, provided the plantis equipped with an active and reactive en-ergy meter.

If no reactive energy meters are installed,the required data can be determined withthe help of a reactive power recorder.

Correction of the Power Factor inNetworks with Harmonics

Consumers with non-linear resistors, i.e.with non-sinusoidal power consumption,cause a distorted voltage waveshape.However, all waveshapes are made up ofsine curves the frequencies of which areinteger multiples of the system frequency the harmonics. When using capacitorsfor power factor correction, the capacity ofthese capacitors and the inductivity of thenetwork (supplying transformer) form a se-ries resonant circuit.The two impedances of the resonance fre-quency are the same and cancel each oth-er out; the relatively low active resistance,however, causes current peaks which maypossibly lead to the tripping of protectiondevices. This may occur if the resonancefrequency equals or is close to the fre-quency of a present harmonic.

This effect can be corrected by the use ofcapacitor units equipped with an inductor.These inductors are designed in such away that the resonance frequency in com-bination with the network inductivity fallsbelow the fifth harmonic. With all higherharmonics, the capacitor unit is then induc-tive which excludes the generation of reso-nances.

We recommend use of these inductor-ca-pacitor units in all cases where more than20% of the power is caused by harmonics-generating equipment.

Compensation in Networks withRipple Control

Ripple control is effected by superimpos-ing the network voltage with signals of afrequency between 160 and 1350 Hz.Since the capacitor conductance is rising ina linear manner in relation to the frequen-cy, these signals can be practically short-circuited. For this reason, the influence ofthe compensation measures should beconsidered and, if inadmissible, it should

be corrected. VDEW (German Utility Board)has issued a recommendation on this sub-ject, where the impedance factor hasbeen defined as the ratio of the networkimpedance to that of the compensationequipment at the frequency of the ripplecontrol signal.

The practical consequence is that in net-works without harmonics and with ripplecontrol frequencies of less than 250 Hz,capacitors without inductors can be usedto correct the power factor at a capacity ofup to 35% of the apparent transformerpower. In this case, follow-up measure-ments can be omitted.

Only in cases with a higher capacitor pow-er should the power supply companies beconsulted for an agreement on the use ofaudio frequency hold-offs. With frequen-cies greater than 250 Hz, capacitor powerswithout audio frequency hold-off are ad-missible only up to 10 kvar. If the capacitorpower exceeds this value, audio frequencyhold-offs are to be integrated. This refersmainly to parallel resonant circuits whichare connected to the capacitors in seriesand which show a high impedance in theirresonance frequency.

In networks where harmonics are clearlypresent, inductor-capacitor units should be

used for compensation in any case. Thespecific type of compensation equipmentis to be selected with consideration of theripple control frequency. Fig. 263 showssome guide values for this procedure.

Compensation of Harmonics

The continuous progress in power semi-conductor technology has resulted in anincreased use of controlled rectifiers andfrequency converters, e.g. for variable-speed drives. The common and character-istic feature of these devices is their non-sinusoidal power consumption. This leadsto distortion of the network voltage, i.e. itcontains harmonics. This distortion is thenforced upon other consumers connectedto the same network and will also have aneffect on higher voltage levels. This disad-vantage may lead to operational failuresand cause a higher apparent power in thenetwork. In order to keep to the limit val-ues as specified in the EN 50160 standard,filtering may become necessary.


20/30


M

M

= 5

= 7

=11

Drive Low-voltage

Transformer

Primary distribution network

Filter

Active power

Reactive power

= 6 k 1, k = 1, 2, 3,

I =1

I1

Fig. 264: Three-phase bridge circuit

Fig. 265: Correction of the power factor with the help of filters

Fig. 266

Fig. 267

Power QualityPassive Compensation Harmonics Filter

The following example shows the harmon-ics present in a typical three-phase, fully-controlled, bridge-circuit rectifier (Fig. 264).

The amplitude of the currents decreasesinversely to the increase of the ordernumber, ideally, in a linear manner in rela-tion to the frequency:

Actually, the values are often slightly high-er, since the DC current is not completelysmoothed. Harmonics of the fifth, seventh,eleventh and thirteenth order may showamplitudes which need to be reduced;harmonics of a higher order can usuallybe neglected.

The effect of harmonic currents on thesystem can be reduced considerably by theuse of filters. This is effected by generat-ing a series resonant circuit from a capaci-tor and an inductor which is then adjustedexactly to the corresponding frequency foreach harmonic to be absorbed. The twoimpedances cancel each other out, so thatthe remaining ohmic resistance is reducedto a negligible amount, compared to thenetwork impedance. The harmonic currentsare absorbed to a large extent; the restremains present in the supply network.This results in a lower voltage distortionand a considerable increase in voltagequality.

Referring to the fundamental component,the filters form a capacitive load. This sup-ports the general reactive power compen-sation. This measure enables the corre-sponding equipment to be designed forlower capacities (Fig. 265).


21/30


Help for Selection

Siemens offers capacitors with and with-out reactors, suitable for single-phase andthree-phase systems for reactive powersbetween 5 and 100 kvar and for nominalvoltages between 230 and 690 V. Thesecapacitors are suitable for the compensa-tion of constant reactive power.

Type Series 4RB

MKK Power Capacitors for fixed compen-sation without reactors, ratings 5 to 25 kvar.The three-phase capacitors can be directlyconnected at the load. Discharge resistor

4RX92 are to be connected in parallel.

Type Series 4RD

MKK power capacitors for fixed compen-sation without reactors, mounted in a pro-tective housing or on a plate. Ratings 5 to100 kvar. Discharge resistors included.

Type Series 4RY

Complete small systems without reactorsfor the automatic stepwise control of thepower factor with and without integratedaudio frequency hold-off in different hous-ings and at different ratings. The units areequipped with a BLR-CC controller suitablefor 8 switching steps. Without audio fre-

quency hold-off, the capacity ranges from10 to 100 kvar, with hold-off from 12 to50 kvar. The nominal voltage for both ver-sions is 400 V, the frequency is 50 Hz.

Larger, fully-equipped systems withoutreactors are delivered in cabinets. Theratings of these systems range from 37.5up to 500 kvar for nominal values between230 V and 690 V and frequencies between50 and 60 Hz. With these systems theSIMEAS C controller for operation in sixswitching steps is used. This controlleroptimizes the switching sequence for con-stant use of the capacitors. For voltagesof 400 V, systems with ratings between75 and 300 kvar and with an integratedaudio frequency hold-off are available.

Type Series 4RY56

Capacitor modules without reactors be-tween 20 and 100 kvar for installation inracks of 600 or 800 mm in width.

Type Series 4RF56

Reactor-capacitor modules from 5 to100 kvar for installation in racks of 600 or800 mm in width.

Type Series 4RF6

Fixed reactor-capacitor units for stationarycompensation in networks with a non-line-ar load percentage of more than 20% re-lated to the supply transformer apparentpower rating. Voltages between 400 and690 V, rating from 5 to 50 kvar. Reactor/capacitor ratios: 5.67%, 7% or 14%.

Type Series 4RF14

Passive, adjusted filter circuits for the ab-sorption of harmonics. Voltages from 400to 690 V, rating from 29 to 195 kvar. In thecourse of project planning, the customer

will be requested to specify the currents ofthe generated harmonics, the harmoniccontent in the higher-level network and theshort-circuit reactance at the connectingpoint.

Type Series 4RF1

Fully-equipped compensation systems withreactor suitable for 400 to 690 V, with acapacitor rating up to 800 kvar and withadditional reactors for a total rating up to1000 kvar. The controller function is real-ized by SIMEAS C.

Type Series 4RF3

Fully-equipped compensation systems withreactors suitable for 400 to 525 V (and alsofor other voltages on request) for ratingsbetween 200 and 400 kvar. Special feature:audio frequency blocking and simultaneousfiltering of harmonics. The controller func-tion is realized by SIMEAS C.

Version

4RF16

4RF17

4RF18

4RF19

Reactor/capacitor

ratio

5.67%

7%

8%

14%

Fig. 268

Fig. 269: 4RY56 Capacitor module 100 kvar, switchableas 2 x 50 kvar module for cable connection

Fig. 270: 4RY19 power factor correction unit in sheet-steel wall cabinet, 50 kvar

Fig. 271: 4RF1 power factor correction unit250 kvar (5 x 50 kvar) in a cabinet 2275 x 625 mm

Power QualityPassive Compensation Selection Guide

For technical data of SIPCON T Passive Filters and Com-pensation Systems see Power Quality Catalog SR 10.6


22/30

6/152 Siemens Power Engineering Guide Transmission and Distribution 4th Edition

Equipment forpower factorcorrection,type 4RF17,reactors (7%).Filtering of 5thharmonic upapprox. 30%

Capacitor type4RB, stationarycompensationequipm. type4RD. Equipmentfor power factorcorrection with-out reactors,type 4RY.

Special audiofrequency hold-off on request orcompensationunit with reactor(7%).

Capacitors andcompensationunits without4RY. Audio fre-quency hold-offon the supplyside.

Ripple control inthe network?

Audio frequency> 250 Hz

U5 < 3%U7 < 2%present in the

network?

Percentage ofnon-linear load inthe network< 20% of Sr*

)

Must resonanceswith the higher-level network beavoided?

Ripple control inthe network?

Audio frequency> 250 Hz? 1

2

*) Sr is the apparent power of the upstream infeeding system (transformer)

Go toflowchart 2

No

No

No

No

No

No

Yes

Yes

Yes

Yes

Yes

Yes

Fig. 272: Flowchart 1: Power factor correction for low, non-linear load

Flowcharts

The flowcharts can be used as a referencewhen selecting the suitable compensationequipment with regard to the individualpreconditions of the specific network.



23/30


1

2

*) Sr is the apparent power of the upstream infeeding system (transformer)

Avoiding resonanceswith higher level network

Partial filtering of self-generated harmonics

Ripple controlpresent in the network?

Audio frequency> 350 Hz?

Audio frequency< 250 Hz?

Filtering a large amountof self-generatedharmonics.

Ripple control presentin the netwok?

Compensationequipment forpower factorcorrection, type4RF16, withreactors (5.67%).Filtering of self-generated 5thharmonic up toapprox. 50%.

4RF34 or 4RF36special reactorconnected powerfactor correctionunit, or powerfactor correctionunit, type 4RF19,with reactors(14%).

Requires specialversion, availableon request.

Passive, tunedfilter circuittype 4RF14 re-quired, availableon request.

Improving thepower factor

Percentage ofnon-linear loadin the network 20% of Sr *

)

No

No Yes

Yes

Yes

No

No NoYes

Yes

Fig. 273: Flowchart 2: Power factor correction for large non-linear load



24/30


SIPCON-DVR/SIPCON-DSTATCOM

Active Filter and CompensationSystems

A great number of industrial processesbased on the supply of electrical energyrequire a high degree of reliability in powersupply, including the constancy of the volt-age applied and the waveshape. A short-time voltage failure or voltage dip may cau-se the destruction of a component presentlybeing processed in an NC machine or of awhole production lot in the semiconductor,

chemical or steel industry. In the automo-tive and semiconductor industries, for ex-ample, the cost incurred by these lossesmay quickly accumulate to millions of dollars.In return, some production processes cau-se unacceptable perturbations in the supplynetwork resulting from voltage dips (rollingmills), flickers and asymmetries (steel mills).

Correction is possible with the help ofactive compensation systems. These sys-tems are capable of absorbing harmonicsand of compensating voltage dips, reactivepower, imbalance in the three-phase sys-tem and flicker problems. Their characteris-tic features go far beyond the capabilitiesof passive systems (e.g. SIPCON T) and

offer great advantages when comparedwith other applications. The function princi-ple is based on a pulse-width modulated,three-phase bridge-circuit rectifier, as usedfor example in variable-speed drives. Theswitching elements IGBTs (insulated gatebipolar transistors) are controlled by meansof pulses of a certain length and phase an-gle. These pulses initiate charging and dis-charging of a capacitor, used as an energystore, at periodical intervals in order to achie-ve the desired effect of influencing the cur-rent flow direction. The control function isperformed by means of a microprocessor-based, programmable control unit.

Advantages of ActiveCompensation Equipment

s No capacitance, in order to exclude thegeneration of undesired resonances.

s Reactive power and harmonics aretreated independently of each other; thecompensation of harmonics has no ef-fect on the power factor and vice versa.

s The audio frequency ripple control levelsremain unaffected.

s Stepless control avoids sudden changesand enables compensation at any de-gree of accuracy.

s Most rapid reaction to load changes with

a minimum delay.s No overvoltages caused by switching

operations.

s The equipment protects itself againstoverload.

s The functions will not be affected byageing of the power capacitors.

s The user can re-configure the system atany time; this greatly enhances flexibility,even if the specific tasks have changed.

Net-work

Load

IGBTConverter

Intermediate-circuit capacitor

Net-work

Load

Fig. 275: DVR

Fig. 274: DSTATCOM

There are two systems available, the DVR(Dynamic Voltage Restorer) and the DSTAT-COM (Distributed Static Compensator)which differ in their specific design and ap-plication. DSTATCOM is designed for paral-lel and the DVR for serial connection.

The DSTATCOM is connected to the net-work between the incoming supply lineand the consumer or a group of consum-ers as shown in Fig. 274. The compensa-tion unit functions as a current source andsink. Correction includes all network char-acteristics related to the reactive power.The DSTATCOM is used to compensateload reactions on the network.

Connection of the DVR requires some moreeffort, since the system is to be loopedinto the line (Fig. 275) in series connection.In this connection, the DVR can influencethe line current flow which enables a com-plete compensation of voltage dips asoccurring, for example, in the event ofshort-circuits in the network. The DVR im-proves the voltage quality of the supplysystem.

Power QualityActive Compensation


25/30


Function Principle

The DSTATCOM unit measures the currentapplied to the supply side and injects a cor-rective current which compensates loadperturbations in the supply system or re-duces them to the admissible amount.Since no capacitors are used for correc-tion, the risk of resonances, as with pas-sive systems, can be neglected. Inductorsare not required.

The signals from the audio frequency rip-ple control systems are not affected. Theuse of audio frequency hold-offs can beomitted.

The DSTATCOM is available in two control

variants: control variant 1 for standard op-eration and variant 2 for flicker mode.

HarmonicsReactive power

ImbalanceFlickers

LoadNet-work

LoadNet-work

LCL filter

PWMIGBT converter

Intermediate-circuit capacitor

DSTATCOM

Fig. 276: Load perturbations are compensated

Fig. 277: Basic diagr am of the DSTATCOM

The DSTATCOM CompensationEquipment

The DSTATCOM is used to compensatereactive power, harmonics, unbalancedload and flickers caused by a consumer.The current supplied from the network ismeasured and modified by injecting correc-tive current in such a way as to preventviolation of the limit values defined for re-active power and for specific harmonicsflowing to the supply system; flicker prob-lems can also be reduced. The power re-quired for this compensation is derivedfrom the intermediate-circuit capacitorwhich is simultaneously re-charged withline current. This line current is also usedto correct the network current. Apart fromthe comparatively low losses, no activepower flow occurs. The DSTATCOM reduc-es or fully compensates perturbations onthe network caused by the consumer.

Fig. 277 shows the basic diagram of thesystem. The IGBT rectifier bridge is con-nected to the network via an LCL filter.The impedance of the inductivity causesthe pulse-width modulated voltage to im-press a current into the network and ab-sorb components of higher frequency.With the help of capacitors, the filter effectwill be improved. DC voltage is applied tothe intermediate-circuit capacitor which isadjusted according to its specific function.The current is measured on the networkside with the result that the correctingfunctions improve the network current andreduce the load reactions on the system.



26/30


Fig. 278: Example: SIPCON DSTATCOM LV

Fig. 279: Steinmetz compensator

Application of Variant 1

This is the standard design used to fulfillthe tasks as described below. All functionscan be performed simultaneously; they arecarried out completely independently anddo not affect each other, as occurs whenusing solutions with passive components(capacitors).

DSTATCOM protects itself against overloadby limiting the current. The individual taskscan be allocated to different priority levels.In case of overload, the tasks with the low-est priority will then be skipped and the de-vice will use its full capacity for the other

tasks. The control functions with the high-est priority level will be the last ones re-maining active.

In this operating mode the DSTATCOMshows excellent dynamic behavior. Withinonly a few network periods, the systemwill reach the setpoint value. Operating var-iant 1 is used for:

s Absorption of Harmonics

A maximum of 4 harmonics up to the13th order, e.g. 5, 7, 11 and 13, are com-pensated. The remaining residual currentcan be adjusted. This option avoids ex-cessive system load, since the increas-ing effect of correction causes a declinein the internal resistance for the corre-

sponding frequency. In return, the load-caused current will considerably increaseand with it the losses, which might re-sult in a system overload. Therefore, it isreasonable to correct the harmonics onlyup to the limit specified by the supplier.

s Reactive Power Compensation

Reactive power compensation, i.e. cor-rection of the power factor, is possiblefor both inductive and capacitive loads.The continuous control principle avoidsswitching peaks and deviations whichmight occur when switching from onestep to the next.

s Correction of Unbalanced Load

Loads in single and two-phase connec-

tion cause voltage imbalance in thethree-phase system which may alsohave negative effects on other consum-ers. Especially three-phase motors maythen be exposed to overheat.

An active load can be symmetrized bymeans of a Steinmetz compensator.While this compensator can correct onlyconstant loads, the SIPCOM is capableof adjusting its correction dynamically tothe load, even if this load is changingquickly.

Three-phasesystem

L1

L2

L3

Activeload

Applications of Variant 2

Variable loads require an even quicker reac-tion than can be realized with variant 1.Therefore, variant 2 has been optimized insuch a way as to enable reactive powercompensation and load balancing withinthe shortest time. Possible applications ofthis variant are:

s Reduction of flickers

Heavy load surges as occurring, for ex-ample, in welding machines, presses orduring the startup of drives, may causevoltage line drops. Fluorescent lampsreact to these voltage drops with varia-tions in their brightness, called flickers.The reactive components of the loadcurrent have usually a greater effect inthis case. The DSTATCOM can be oper-ated in the flicker mode which providesan optimized reaction within the shortesttime in order to reduce these voltagevariations to a large extent. The delaytime of the system is only 1/60 of theperiod length and control is completedwithin one network period.

s Correction of unbalanced load conditions

The DSTATCOM is suitable to fully cor-rect unbalanced loads of the three phas-es. Until now, this was achieved withthe help of stepwise controlled inductorsand capacitors, but now correction canbe performed continuously and veryprecisely. The quick reaction of theDSTATCOM in the f licker mode enablescontrol within only one network period.Consumers in single or two-phase con-nection, such as welding devices, willno longer affect symmetry.



27/30


The whole nominal current of the DSTATCOM can beused for the filtering of harmonics.Reactive power compensation and load balancing canalso be performed.This function should be used if the device is mainly usedfor the filtering of harmonics

Only 50% of the DSTATCOM nominal current is usedfor the filtering of harmonics.The remaining current can be used for reactive powercompensation and load balancing.

Instead of harmonics filtering, the whole nominal current

is used to perform highly dynamic reactive powercompensation and load balancing.Compared with other control variants, the dynamicbehavior is many times better.

100% use for the filteringof harmonics

50% use for the filteringof harmonics

Flicker mode

Requirednominal current

The required nominal current for the DSTATCOM iscalculated as the geometrical sum of the required partialcurrents according to the following formula:

Control rangeDSTATCOM

Net-work

Load

SIPCONDSTATCOM

Permanentcompensation

Control rangeof a DSTATCOMwith permanentcompensation

2 x capacitive

capacitive

inductive

Fig. 280: Application modes of DSTATCOM

Fig. 281: Displaced control range


When selecting a DSTATCOM, three as-pects should be considered:

1. The nominal voltage.Nominal voltages of 400 V, 525 V, 690 Vand for medium-voltage applications upto 20 kV.

2. The supply current ISN required by theDSTATCOM.

3. The type of application.

Application can be broken down intothree types of different tasks (Fig. 280).

I1 = Reactive component ofthe fundamental currentcomponent

I5I13 = Current harmonics

ISN

= I12+ I52+ I72+ I112+ I132


SIPCON can be used for the generation ofeither capacitive or inductive reactive cur-rent. Since the latter can usually be neglect-ed as regards reactive power compensa-tion, the working point of the DSTATCOMcan be displaced by means of fixed com-pensation with the help of traditional com-pensation (SIPCON T). The power of theDSTATCOM can thus be almost doubled.(Fig. 281).


28/30


LoadNet-work

IGBT converter LCL filter

The DVR Compensation Equipment

The DVR unit is used to correct interferinginfluences from the supply network on theconsumer. Short-time and even longer volt-age dips, harmonics and unbalanced loadmay cause considerable damage to sensi-tive consumers. The DVR has been de-signed for the compensation of such faultsin order to improve the quality in powersupply and to prevent production loss anddamage.

Function PrincipleThe DVR is used as a voltage sourcewhich is integrated in the feeder line be-tween the supply system and the consum-er in series connection. The voltage ap-plied to the consumer is measured and if itdeviates from the ideal values, the missingcomponents will be injected, so that theconsumer voltage remains constant. Apartfrom the prevention of voltage dips, theDVR is also used to correct overvoltagesand unsymmetries. The highly dynamicsystem is capable of realizing the full com-pensation of voltage dips within a period of2 to 3 milliseconds.

Voltage dipsVoltage overshootsHarmonicsImbalance

LoadNet-work

Fig. 282: Improving the quali ty in power supply Fig. 283: Block diagram DVR



29/30



In contrast to the principle of SIPCONDSTATCOM, which corrects the reactivepower only for the parallel-connected load,the whole load current flows through theDVR system. Therefore, all preconditionsand marginal conditions are to be consid-ered to enable correct configuration. Basi-cally, the following points should be takeninto account:

s Fault characteristics:

What kind of network faults are to becorrected (single, two or three-phase)and up to which residual voltage value

and fault duration shall correction be-come effective.

s Load:

Nominal value of the apparent power,type of load, e.g. what types of drive,resistance load, etc. are to be suppliedwith the help of the DVR.

s Corrective behavior:

What degree of accuracy is to be ob-served for the voltage on the load side.

It will often be sufficient if the DVR sup-plies only part of the nominal load. To en-sure correct project planning, a Siemensexpert should be consulted.

The signals from audio frequency ripplecontrol systems are not affected. An audiofrequency hold-off is not required.

Application

The DVR is basically used to improve thequality of the voltage supplied by the pow-er supply system.

s Correction of voltage variations

Remote short-circuits in the supply net-work occasionally result in voltage dipsof different strength and of a duration ofonly few tenths of a second. In weaknetworks it may also occur that the usu-

al voltage limits cannot be held over along period of time or that sensitive con-sumers require smaller tolerances thanoffered by the power supply company.

With the DVR, single, two and three-phase voltage dips up to a certain inten-sity can be compensated independentlyof their duration. Additional power is tak-en from the rectifier part from the net-work, even if the voltage is too low; thispower is then supplied to the seriestransformer on the load side via the con-verter. The value of the nominal powerof the DVR is reciprocal to the voltagesto be corrected. Statistics show thatmost of the short-time voltage dips havea residual voltage of at least 70 to 80%.

The power to be generated by the DVRmust be sufficient to compensate themissing part.

s Compensation of unbalanced load

The DVR can be used to inject a positivephase-sequence voltage which enablesthe compensation of imbalance in thesupply voltage in order to avoid exces-sive temperatures of three-phase ma-chines.

s Absorption of harmonics

The quick-action control of the DVR ena-bles elimination of harmonics by correct-ing distortions of the voltage waveshape.Since the system can be configured fordifferent tasks, it can also be used toprocess harmonics of the fifth, seventh,eleventh and thirteenth order, either sep-arately or as a whole.

Further information:

www.powerquality.de



30/30

power quality measuring, recording, compensation

Documents