SCADA & Digital SubstationElizabeth Johnson & Ritesh Bharat

GRID

Introduction to Digital Substations

INTRODUCTIONThe demand of electrical energy led the Utilities to develop High and Ultra High Voltage networks using AC and DC technology (1100 1200 kVAC ; 800 1100 kVDC) Control, Protection, Metering and all other IEDs are using digital electronics and should be able to communicate with IEC 61850 Standard Instrument Transformers are the link between the UHV line and the Protections and all secondary equipment ; They have to be designed for higher insulation levels, higher short circuit current capability, higher bandwidth extended dynamic range and high accuracy (primary current : 1A to 50 kA) New technologies are developed to meet new demanding requirements: DIT (Digital Instrument Transformers; CT and VT), or NCIT Digital Communications between Process apparatus and Bay/Station level Control and Monitoring of active mechanisms (CB and DSC)

What is Digital Substation ? A global association of IEDs in the substation, including:Smart intelligent DCS (Digital Control System) New technologies of Instrument Transformers (NCITs) MergingMerging-units for Sampled Values (CTs, VTs, NCITs) Digital Controllers for Circuit-Breakers and Disconnectors CircuitOnOn-line conditioning Monitoring (CB, DSC, GIS, TRANSFO) Smart Grid

All these IEDs communicating together with digital standardized protocols defined in IEC 61850

Digital Instrument Transformers How do they work?

Optical CT Principle Faraday Effect

Michael Faraday (17911867)

Optical transparent medium

I

Light polarization vector Light propagation axis

HCurrent busbar

Rotation of the polarization plane of an optical wave, traveling in a magneto-optic material, under the influence of a magnetic field parallel to the direction of propagation of the optical wave

PRINCIPLE OF OPERATION

A light source sends light through a waveguide to a linear polarizer, then to a polarization splitter (creating two linearly polarized light waves), and finally to an optical phase modulator. This light is then sent from the control room to the sensor head by an optical fiber. The light passes through a quarter wave plate creating right and left hand circularly polarized light from the two linearly polarized light waves. The two light waves traverse the fiber sensing loop around the conductor, reflect off a mirror at the end of the fiber loop, and return along the same path. While encircling the conductor, the magnetic field induced by the current flowing in the conductor creates a differential optical phase shift between the two light waves due to the Faraday effect. The two optical waves travel back through the optical circuit and are finally routed to the optical detector where the electronics de-modulate the light waves to determine the phase shift. The phase shift between the two light waves is proportional to current and an analog or digital signal representing the current is provided by the electronics to the end user.

Why Optical CTs?Safety Intelligence and flexibility Availability Wire => Electric Power Optical Fiber => Information

- - P 8

Safety

The optical CT does not touch the electrical power on the line. High voltage and ground are well separated with all dielectric insulation. The insulation contains no fuel.

- - P 9

Intelligence and Flexibility

The optical sensor is fully self-diagnostic. Extremely high fidelity current measurements allow for improved system diagnostics Software configurability

- - P 10

Availability Improved system availability is a consequence of safety and intelligence Unmatched reliability of outdoor equipment Electronics interchangeability + redundancy means no down time.

- - P 11

NCIT BenefitsDIGITAL Intelligence for SMART GRIDs, smart redundancy, Ethernet connectivity (IEC 61850), self diagnostic,.. SAFETY No HV coupling, no measurement service loss in event of a failure ENVIRONMENTAL No oil, no SF6, no copper, zero footprint (for CTs), less mass ACCURACY Wide dynamic range (extended range) frequency response DC to 10 kHz (includes the 100th harmonic) ADAPTABILITY Easy installation and cabling, easy on-site testing, universal design software configurable, flexible form factor AVAILABILITY Zero outdoor maintenance, electronics inter-changeability, HV passivity, short lead time, redundancy

Hardware modification in Analogue ModulesNo need of Analogue CT & VT inputs

Digital CT & VT input board with IEC 61850-9-2

Analogue inputs are replaced by Ethernet connection13

IEC 61850 Process BusDigitalization and Transmission of CT and VT measurements multicast Digital Standardized Interface are a challenge But, It gives major benefits cabling simplifications costs reductions introduction of NCIT measurement systems permanent self-monitoring safety etc.

on

And Digital Control of Circuit-Breakers and Disconnectors

Types of Merging Units

AMU : Analog Merging Unit Interface with conventional instrument transformers

DMU : Digital Merging Unit Interface with CB / isolators / earth switches

IMU : Integrated Merging Unit Combination of AMU and DMU

NMU : Numerical Merging Unit Interface with digital instrument transformers

Typical Merging Unit

CT / VT Signals in the Protection

Comtrade file NCIT measurement In the protection

Comtrade file CIT measurement In the protection

Distance Protection P444 - results

With digital 9-2LE interface

Conventional analogue interface

Intelligent Primary Equipments

GISLocal Cubicle (LCC)CEVT-P/M CEVT-P/M CEVT-P/MAnalogue connections Synchro 1pps MICOM P594

PCtri-U

FO - Ethernet 100BaseFx

PCtri-IRECT-P/M RECT-P/M RECT-P/MAnalogue connections

N M U

IEC 61850-8-1

X

IEC 61850-9-2LE Or other protocol

X X

IEC 61850-9-2LE Or other protocol

Digital/Analog Converter METER

PCtri-I : 3-phased current Primary Converter with Ethernet ports PCtri-U : 3-phased voltage Primary Converter with Ethernet ports

GRIDBOX Controller and Monitoring for Circuit BreakerGRIDBOX can control and monitor standard alarms on breaker, transformer, disconnectors etc.

GRIDBOX Controller and Monitoring for Circuit BreakerMain Features Replace copper by optic fibber Circuit breaker full monitoring Trip Coil Supervision Electrical/mechanical wear Open/close travelling signature Local static command of coils Network synchronized time stamps of events (GPS or IEEE1588) IEC61850 communication Advantage Decrease substation reconstruction cost Increase communication reliability between the field equipment and control building Benefit from accurate planning of maintenance/refurbishment/replacement Obtain real time detection of equipment availability Reduce command response time

DMC (Digital Motorized Control) for Disconnectors

The DMC device is installed inside motor operating mechanism applied to disconnect switches. The DMC device is designed to totally control the movement of the disconnect switch during opening and closing operations with an integrated electronic module The DMC allows the control mechanism (mechanical parts can be monitored both locally and remotely)

FeaturesNew operating mechanism equipped with DMC device features:

Stainless steel box Irreversible gearbox Robust design to cope with adverse environmental conditions Can be adjusted for any motor supply voltage Less cabling and wiring Reduced maintenance cost by preventive maintenance Variable speed during the operations GRID Modularity on the configuration to suit any type of installation

DMC Installation

DMC device is installed inside ALSTOM motor operating mechanism CMM series.

GRID

Monitoring BenefitDMC device permit to the user to:

Archive curve which facilitates ageing and maintenance studies Evaluate the state of kinematic chain and live part position during the operation Continuously monitor the control circuit Control the real end open-close position of disconnector Obtain a precise indication of the operation times Record load curves in real time for a general evaluation before and after the maintenance and repairing Controls torque to operate the disconnectorGRID

Offer a flexible configuration based on the different disconnector type

Monitoring SpecificationDMC device monitors/controls following parameters as a function of position and time:

Voltage Current Operating time Disconnector in motion/not in motion N of operation cycle Max current reached Minimum voltage reachedGRID Data are recorded in non-volatile memory and transferred via telecommunications serial RS 232.

Summary Motor power supply voltage : from 90Vdc 250Vdc / 110-400 Vac 50/60Hz Remote control command power supply voltage: from 90Vdc-250Vdc / 90Vac-220Vac Variable speed configurable Mode of operation : Remote-Local-Manual Electrical connection on terminal board and connectors Electrical interlocking motor/manual operation Real time monitoring of the disconnectors state Data recording for diagnostic Cams switch positioning system Serial output comunication RS 232 with local PCGRID

Programmable positioning signal management with dedicated free contacts on terminal board

DMC Architecture with a concentrator D-DSC

3 x DMC A B C A

3 x DMC B C

Prot1 Prot2 Met A B 3 x DMC C A

ICBus

D-DSC

IEC 61850-8-1

BCUB 3 x DMC C

Optical Fibers

Prot A Met B 3 x DMC C

DMC / IEC 61850-8-1

System Architecture in Digital Substations

COSI

Digital Substation

SYSTEM ARCHITECTURE IEC 61850-8.1 & 9.2

GPSLOAD CENTERS OPERATOR WORKSTATION IRIG-B

IEC 60870-5-101 Protections

IEC 60870-5-104Ethernet

ENGINEERING WORKSTATION

REMOTE ACCESS

SNTP MODEM RS232 GATEWAY

MODEM

Switch

ETHERNET OPTICAL LAN IEC61850-8.1 100MBpsSNTP

Switch IRIG-B

SNTP

Bay Computer

Bay Computer

Bay Computer

Bay Computer

SNTP

IEC 61850-8.1IEC 61850-8.1

Protections xn

IEC 60870-5-103

IEC 60870-5-103

IEC 60870-5-103

MODBUS

CT/VT

TC TS TM 4-20mA IRIG-B

Protections xnIRIG-B

Protections xnIRIG-B

Protections xn

AVR

SNTP

GPSSwitch 1PPS 1PPS

IEC 61850-9.2Switch 1PPS

AVR

IRIG-B

Merging Units

IEC 61850-8.1

CIT = Conventional Instrument Transformers

NCIT = Non Conventional Instrument Transformers

System Architecture

XMU SELECTOR BB

DMC

DMC

DMC

DMC

DDSC

DDSC

DCCB

DCCB

PROT XMUDMC

PROT XMUDMC

BCU

BCU

Process Bus SV Process Bus GOOSE Station Bus

DMC

DMC

DCS PACIS ETHERNET OPTICAL LAN 100 Mbps IEC 61850-8-1

COSI-NXCT Mounted on Live Tank CBs

National Grid, UKNXCT on a Siemens 420 kV live tank circuit breaker

Alstom GL317 with NCITEnel Terna, Italy Candia S/S,420 kV COSI-NXCT on VATECH live tank circuit breaker

COSI NXCT on CBExample of 400 kV OHL feeder400kV OHL feeder bay

400kV OHL feeder bay with NXCT on LTCB

OHL feeder Comparison : footprint saving 15%

ConclusionsNCITs & Process Bus offer huge potential advantages Cost and Space savings Interoperability : Digital Standard IEC 61850 Safety Reliability Availability Measurement Improvements

Thank You

www.alstom.com