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Non-conventional Instrument Transformers: CP3

Lars Andersson

ABB Switzerland

Summer Workshop of Swiss Chapter of IEEE PES, 05-06-02

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ELK 3 GIS

Um = 550 kVIn = 4000 A

BIL = 1550 kV63 kA Breaking

current

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Voltage Transformer ELK PI3

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Current Transformer ELK CB3

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Why Non-conventional Instrument Transformers?

Only one multi-purpose ECT/EVT for all applicationsFeeder and station protectionRevenue metering

Wide dynamic range No project specific dimensioning and manufacturing

Cost reductionLower costNo CT/VT specific engineering cost

Higher availability of the primary equipmentHigher safety

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ELK-CP3

Combined electronic voltage and current transducer (EVT/ECT) according to IEC 60044-7 and IEC 60044-8. Two fully independent measurement systems, each with protection and metering data.

Current: 100A – 4000A 0.2S / 5P TPE

Voltage: 330 ... 550 kV/√30.2 / 3P

BW: 1000 Hz (-3 dB), fulfillsIEC 60044-8 power metering

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ELK-CP3 componentsELK-CP3 consists of 3 main components

A single phase primary convertercontaining two independent sets of voltage sensors and Rogowski coilsTwo redundant secondary convertersmounted directly on the primary converter, containing signal acquisition, signal processing and digital transmission circuits.Merging units to merge and time correlate the data from 3 / 9 sensor units. Output interface on Ethernet link, according to IEC61850-9-1 / 9-2. (Separate devices for Metering and Control & Protection applications)

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Metering System

One CP3 per phase

MeteringMerging Unit

LA

LB

LC

IEC 61850-9-1to the Meters

Two independent measurement

chains

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Protection System

Protection Merging Unit

LA

LB

LC

IEC 61850-9-2to Control andProtection

One CP3 per phaseTwo

independent measurement

chains

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Protection layout example

BZ11

BZ12

BZ32

BZ22

BZ21

BZ31

Q01

Q02

Q03BZ23

ShR, SVC, ShCTertBranch

ShR

YY∆

BZ13

BZ2

I-BZ1

BZ51

BZ61

BZ1

TR-OpS

BZ2

I-BZ1

YY

TR-Neut

∆

TR-NeutOpSShR

TR-3rdW

CT positioning old layouts

Example: 1½ Breaker, 6 CTs per DiameterCost-optimized Layout

I-BZ13

I-BZ13

CP replacing CT and VT

CP

CP

Example: DBB, 2 CTs per BreakerCost-optimized Layout

CP

CP

CT positioning old layouts

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Reliability

ABB has installed since 1998 about 350 combined voltage and current sensors, mainly in hybrid GIS (PASS) substations in Australia (Powerlink Queensland)No primary converter failuresMTBF (Major Failures) >1400 service device-years

Substation Braemar,90 Combined current and voltage sensorsRedundant busbar and feeder protection with digital optical inputsCommissioning date 2000-08-30

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Example of Actuator: Motor Breaker Drive

One moving part only

Controlled Motion => Lower Mechanical Stress

Self supervision

Micro-motion: Built in function test

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Trends and Vision

Facts: Today we have some sensors and actuators with a mix of standardised and proprietary connections to the protection and control devices

Trends: Tomorrow we will have an increasing amount of sensors and actuators with standardised links to protection and control based on IEC61850

Vision: In the future we will have yet more sensors and actuators, connected to the protection and control via an IEC61850 based network

ABB

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Spare slides

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ELK-CP3 Sectional View

Secondary Converter

Voltage SensorElectrode

Rogowski Coil

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Key DataCP 3 is a combined electronic voltage and current transducer (EVT/ECT) according to IEC 60044-7 and IEC 60044-8.Current transducer

Accuracy class 0.2S / 5TPE (120 ms)Nominal current 100 A ... 4000 A

Voltage transducerAccuracy class 0.2 / 3PNominal Voltage 330 ... 550 kV/√3

Bandwidth 1000 Hz (-3 dB), fulfillsIEC 60044-8 power

meteringAmbient temperatureprimary/secondary converter -40°C ... +40°CAmbient temperaturemerging unit -5°C ... +55°C

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IEC 61850: More than a Protocol (1)

IEC 61850 defines communication requirements that all devices have to comply with

IEC 68150 defines Conformance Tests and Engineering support

IEC 61850 defines general device requirements, e.g. environmental requirements

IEC 61850 defines strong extension rules

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Digital Interfaces IEC 61850-9-2LE

Ethernet Interface 100BaseFxSimultaneous transmission of two data streams

80 * fr: 4000 Hz (fr= 50 Hz); 4800 Hz (fr= 60 Hz) for Metering20 * fr: 1000 Hz (fr= 50 Hz); 1200 Hz (fr= 60 Hz) for Protection256 * fr: for power quality metering

Variable delay time (max. 3 ms), additional PPS signal where requiredCan be transmitted on process busses carrying other IEC 61850-8-1 telegrams.

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Router IEC 61850-8-1

Ethernet Ring with Switches

MU withNCITs

Relay Y

MU withNCITs

Relay Y

System Architecture with IEC 61850-9-2Control Center HMI Engineering

Relay X1

Bay Controller

Conventional Switchgear

MU X withNCITs

Relay X2

Relay X1

Bay Controller

Conventional Switchgear

MU X withNCITs

Relay X2

IEC 61850-9-2

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Main ZProtection

Merging Unit

ArevaSensor

Bay Controller

Main Y Protection

Main X Protection

Trips

Merging Unit

3rd Fibre

IEC 61850-9-2/8-1(GOOSE, SAV, MMS)

IEC 61850-8-1 (GOOSE)

IEC 61850-8-1(MMS, GOOSE)

IEC 61850-9-2 (SAV)

IEC 61850-9-2 (SAV)

IEC 61850-9-2 (SAV)

Ethernet Switch

Simulator

IEC 61850-8IEC 61850-9

Cigré 2004

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ELK 3 GIS

VT

CT

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Voltage Sensor

Principle Equivalent circuitEnclosure(Ground)

Kapton foil

Sensor electrode

SF6

High voltageconductor

C1

C2 R1

R1

u2

SF6 gas capacitor

Foil capacitor

u2

u1

u1

Precision resistorVISHAY

VH202 (Z-Foil)

dtduRCu 1

12 =22

1RC

fπ

<<for

C1

C2

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Current SensorThe current sensor consists of a toroidal Rogowski coil, wound on an epoxy core. The coil is completely enclosed in an epoxy cast and electrically shielded by the enclosure.

B1

i1

R

ParamagneticalCore

Rc Lc

Rdi1dtM

dtdiMuind 1=

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ABB FOCSFiber-Optic CurrentSensor

Klaus Bohnertcontribution presented by

Hubert BrändleABB Switzerland

Summer Workshop of Swiss Chapter of IEEE PES, 05-06-02

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ABB FOCS - Fiber-optic current sensor

FOCS for high-voltagesubstations

FOCS for electrochemicalindustry

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No magnetic saturation

Small size and low weight

Integration into circuit breakers, bushings, etc

Smaller installation costs

High accuracy, large dynamic range

High bandwidth

Substation electronics isolated from high voltage

No risk of catastrophic failure (explosion)

Optical Current Sensor in HV Substations

Merits

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Fiber-Optic Current Sensor (FOCS)

Sensing fiber coil

retarder

Currentconductor

Left and right circular light waves

xy

xy

Fiber

Orthogonal linear light waves

Light source, detection, signal processor

Reflector

∆φ∆φF

out

Current-induced phase shift: ∫ •=∆ dsHNVF 4φ

∆φF = 4 V N I

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Fiber Quarterwave Retarder

45°

linear polarization

circularpolarization

LB/4

elliptical- core fiber λ/4 retarder

fiber core

~ 1.5 mm

elliptical-core fiber

sensing fiber

λ/4

45° splice

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80 90 1001.00

1.01

1.02

1.03

1.04

-40°C

Nor

mal

ized

Sca

le F

acto

r

Retardation (deg)

Reflective current sensor

90°C

-40 -20 0 20 40 60 80

1.00

1.01

1.02

(1/V) δV/δT = 0.7x10-4 °C-1

effect of temperature dependent retarder, ρ = 100.4°

with (1/ρ) δρ/δT = -2.2x10-4°C-1

combined contributions

contribution from temperature-dependent Verdet constant

Nor

mal

ized

Sca

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acto

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Temperature (°C)

Temperature Compensation of Faraday Effectretardation ρ

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Output

Optical fiber coil

Current conductor

Light source & signal processor

Output

Optical fiber coil

Current conductorCurrent

conductor

Light source & signal processor Fiber cable

FOCS for HV Circuit Breaker

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FOCS for HV Circuit Breaker

Fiber cable

Current

SF6 gas Circuit breaker

Sensor electronics

Sensing fiber coil

Fiber cable

Current

SF6 gas Circuit breaker

Sensor electronics

Sensing fiber coil

Conventional currentmeasurement

Circuit breakers

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FOCS for HV Circuit BreakerConventional 170 kV current

transformersSensor installationin 170 kV breaker

Current sensor

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FOCS for Electrochemical Industry Aluminum smelting (Hall-Heroult

process)- Al2O3 is dissolved in molten cryolite (Na3AlF6)

- Pure Al is produced by electrolysis:

2Al2O3 + 3C ---> 4Al + 3CO2

Total smelter current: up to 500 kA

Energy use: 15.7 kWh / kg Al

World production in 2002: 21.2 Million tons

(110 smelters)

Carbon anodes

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Hall Effect Based DC Current Transformers

400 kA

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Fiber-Optic Current Sensor

current

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Fiber-Optic Current Sensor

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FOCS for Power Rectifier

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Signal vs Current

10 100

10

100

Sig

nal (

kA)

Current (kA)

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1

2

Relative error (%

)±1%

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experiment

theory

Sensor Signal vs Fiber Coil Temperature

-20 0 20 40 60 800.992

0.996

1.000

1.004

1.008Constant current

Sign

al (n

orm

aliz

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Coil temperature (°C)

±0.1%

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0 6 12 18 240.996

0.998

1.000

1.002

1.004

Sign

al (n

orm

aliz

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Time (hours)

Signal vs Time

Signal at constant current

24 h period 50 day period

0 10 20 30 40 500.996

0.998

1.000

1.002

1.004

Sign

al (n

orm

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Time (days)

±0.1 % ±0.1 %I = 7693 A DC, 1 fiber loop

Data points with 1s averaging

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Signal vs Conductor Position

Fiber coil

±0.1 %

I = const

0.0 0.2 0.4 0.6 0.8 1.00.998

0.999

1.000

1.001

1.002Si

gnal

(nor

mal

ized

)

Conductor position

Conductor

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FOCS Calibration

Reproducibility at repeated sensor head assembly and disassembly

1 2 3 40.998

0.999

1.000

1.001

1.002Constant current

+/-0.1%

Nor

mal

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sig

nal

Repetition number

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Sensor Insensitive to Vibration

0 2 4 6 8 10

0

5

10

15

coilhousing

vibration direction :

vibration frequency = 50 HzSi

gnal

in te

rms

of e

quiv

alen

t cur

rent

(Arm

s)

Acceleration (g)

Vibration-induced signal versus acceleration

Sensor for high-voltage substation

Vibration

Coil housing

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ABB Fiber-Optic Current Sensor

Nominated for Swiss Technology Award 2005, Hermes Award 2005