Digital Substation Alstom

GRID

SCADA & Digital Substation

Elizabeth Johnson & Ritesh Bharat

INTRODUCTION

The 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 » ?

Smart «

Smart « intelligentintelligent » DCS (Digital Control System) » DCS (Digital Control System)  _{Smart GridSmart Grid} New technologies of Instrument Transformers (NCITs)

New technologies of Instrument Transformers (NCITs) Merging

Merging--units for Sampled Values (CTs, VTs, NCITs)units for Sampled Values (CTs, VTs, NCITs) Digital Controllers for Circuit

Digital Controllers for Circuit--Breakers and DisconnectorsBreakers and Disconnectors On

On--line conditioning Monitoring (CB, DSC, GIS, TRANSFO)line conditioning Monitoring (CB, DSC, GIS, TRANSFO)

All these IEDs communicating together with digital

All these IEDs communicating together with digital

standardized protocols defined in

standardized protocols defined in IEC 61850

IEC 61850

Optical CT Principle – Faraday Effect

II

H

H





Optical transparent medium Light polarization vector Light propagation axis

Current busbar

Michael Faraday (1791－1867)

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.

- - P 8

Why Optical CTs?

Safety

Intelligence and flexibility Availability

Wire => Electric Power

- - P 9

Safety

 _{The optical CT does not “touch” the}

electrical power on the line.

 _{High voltage and ground are well}

separated with all dielectric insulation.

- - P 10

Intelligence and Flexibility

 _{The optical sensor is fully self-diagnostic.}

 _{Extremely high fidelity current measurements allow for improved system}

diagnostics

- - P 11

Availability

 _{Improved system availability is a consequence of safety and intelligence}

 _{Unmatched reliability of outdoor equipment}

DIGITAL

− Intelligence for SMART GRIDs, smart redundancy, Ethernet connectivity (IEC 61850), self diagnostic,..

NCIT Benefits

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 Modules”

13

No need of Analogue CT & VT inputs

Analogue inputs are replaced by Ethernet connection

Digital

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

Digitalization and Transmission of CT and VT measurements on 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.…

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}

CT / VT Signals in the Protection

Comtrade file NCIT measurement In the protection Comtrade file CIT measurement In the protection

With digital 9-2LE interface Conventional analogue interface

PCtri-U PCtri-I RECT-P/M RECT-P/M RECT-P/M CEVT-P/M CEVT-P/M CEVT-P/M N M

U _{Or other protocol}IEC 61850-9-2LE X

IEC 61850-9-2LE Or other protocol X IEC 61850-8-1 X Analogue connections Analogue connections FO - Ethernet 100BaseFx

GIS

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

Synchro – 1pps MICOM P594 Digital/Analog Converter METER Local Cubicle (LCC)

GRIDBOX can control and monitor standard alarms on breaker, transformer, disconnectors etc….

Main 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

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)

GRID

Features

New 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

DMC Installation

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

GRID

Monitoring Benefit

DMC 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 disconnector

GRID

Monitoring Specification

DMC 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 reached

•

Data are recorded in non-volatile memory and transferred via telecommunications serial RS 232.

GRID

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 disconnector’s state

•

Data recording for diagnostic

•

Cams switch positioning system

•

Serial output comunication RS 232 with local PC

DMC Architecture with a “concentrator D-DSC”

DMC / IEC 61850-8-1 A B C 3 x DMC A B C 3 x DMC A B C 3 x DMC D-DSC A B C 3 x DMC Prot1 Prot2 Met Prot Met IEC 61850-8-1 I²CBus Optical Fibers A B C 3 x DMC BCU

COSI

System Architecture in Digital Substations

SYSTEM ARCHITECTURE IEC 61850-8.1 & 9.2 Protections IRIG-B IRIG-B OPERATOR WORKSTATION Switch GATEWAY

IEC 60870-5-101 ENGINEERING WORKSTATION

MODEM REMOTE ACCESS MODEM LOAD CENTERS Switch IEC 60870-5-104 Ethernet RS232

ETHERNET OPTICAL LAN IEC61850-8.1 100MBps Bay Computer IEC 6 0 8 7 0 -5 -1 0 3 Bay Computer Bay Computer Protections x n IRIG-B M O D B U S Protections x n AVR Protections x n IEC 6 0 8 7 0 -5 -1 0 3 IEC 6 0 8 7 0 -5 -1 0 3 CT/VT TC TS TM 4-20mA IEC 61850-8.1 Bay Computer Switch Switch IEC 61850-9.2 AVR IRIG-B IRIG-B

NCIT = Non Conventional Instrument Transformers

SNTP SNTP SNTP GPS Merging Units IEC 61850-8.1 SNTP 1PPS 1PPS GPS 1PPS IRIG-B Protections x n

CIT = Conventional Instrument Transformers

IE C 6 1 8 5 0 -8 .1 SNTP

System Architecture

DCCB DDSC XMU PROT BCU DMC DMC DMC DMC XMU SELECTOR BB DCCB DDSC XMU PROT BCU DMC DMC DMC DMC

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

Process Bus SV

Process Bus GOOSE

COSI-NXCT Mounted on Live Tank CBs

Alstom GL317 with NCIT

National Grid, UK

NXCT on a Siemens 420 kV live tank circuit breaker

Enel Terna, Italy Candia S/S,

420 kV COSI-NXCT on VATECH live tank circuit breaker

COSI NXCT on CB

Example of 400 kV OHL feeder

400kV OHL feeder bay

400kV OHL feeder bay with NXCT on LTCB

OHL feeder Comparison :

NCITs & Process Bus offer huge potential advantages Cost and Space savings

Interoperability : Digital Standard IEC 61850 Safety

Reliability Availability

Measurement Improvements

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