Central power research institute report

Central Power Research Institute (CPRI) REPORT BY

MAYUR DHANAJI RANE (1540)

Central Power Research Institute

2

National Power Training Institute

Power System Training Institute

Central Power Research Institute (CPRI)

Submitted By: -

Mr. Mayur Dhanaji Rane (1540)

Guided By:-

Mr. K. Vetrivel Mr. M. N. Murthy

Assistant Director, Director, PSTI,

PSTI, Bangalore Bangalore


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Index

Sr. No Contents Page No.

1 Introduction 4

2 Centre for Collaborative and Advanced Research 5

3 Diagnostics Cable & Capacitor Division 6

4 Dielectric Materials Division 13

5 Energy Efficiency & Renewable Energy Division 14

6 High Power Laboratories 14

7 High Voltage Division 18

8 Short Circuit Division 24

9 CPRI Organization Chart 29

10 Bibliography 30


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1 Introduction:-

Central Power Research Institute (CPRI) is the power house of the Indian

electrical industry. Set up in 1960 by the Government of India, it functions as a

centre for applied research in electrical power engineering assisting the electrical

industry in product development and quality assurance. CPRI also serves as an

independent authority for testing and certification of power equipment. CPRI's

governing body includes eminent professionals from industries & utilities,

prestigious academic and research institutions & the government. It employs over

300 highly qualified and experienced engineers & scientists besides other

supporting staff.

MISSION

"To carry out applied research and provide quality services for

achieving reliability and economy in Power Systems through excellent

facilities, commitment and best practices, ensuring self-sustenance."

VALUE

"We value customer satisfaction by sharing our knowledge and caring for their

needs, maintaining total transparency in our operations"

ATTITUDE

"Together we strive to learn more and serve the Society better with an open mind

and futuristic outlook, always willing to accept new challenges."

� Departments:

• Centre for Collaborative Advanced Research (CCAR)

• Diagnostics Cable & Capacitor Division (DCCD)

• Dielectric Materials Division (DMD)

• Distribution Systems Division (DSD)

• Earthquake Engineering & Vibration Research Centre (EVRC)

• Electrical Appliances Technology Division (EATD)

• Energy Efficiency and Renewable Energy Division (ERED)


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• High Power Laboratory (HPL)

• High Voltage Division (HVD)

• Instrumentation Division (ID)

• Materials Technology Division (MTD)

• Mechanical Engineering Division (MED)

• Power System Division (PSD)

• Short Circuit Division (SCD)

• Utility Automation Research Centre (UARC)

2. Centre for Collaborative and Advanced Research (CCAR) Many utilities in India require research facilities and expert advise to address

various issues and problems in the context of expansion and restructuring of the

power sector. There is need for a nodal center to provide unified services in the

form of collaborative research in advanced areas. Such a center would also enable

up gradation of skills of engineers and professionals in power sector through

workshops and training programs. Based on this, Government of India approved,

the Center for Collaborative and Advanced Research (CCAR) to be located at

CPRl's Bangalore unit. One program already initiated to take forward the R&D

needs in The National Perspective Plan for R&D in Indian Power Sector,

conceptualized by National standing committee for R&D.

R & D Programs Of CCAR :

• Power Transmission Technologies

• Power Distribution Technologies including Energy Metering

• Power System Simulation, Studies and Modeling (HVDC, FACTS, etc)

• Information Technology in Power Sector and Distribution Automation

• Energy Audit and Conservation

• Reforms and Regulatory Mechanism

• Ultra High Voltage Engineering

• Diagnostics Techniques and RLA Studies

• Vibration Research and Seismic Testing

• Environmental Protection


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3 Diagnostics Cable & Capacitor Division (DCCD):-

Diagnostic Tests:

S. No. Products/Apparatus Type of Tests conducted

01 • Power Transformer • Polarization Index Test

• Dielectric loss angle and Capacitance

at 50 Hz

• Dielectric spectroscopy for Frequency

Domain Analysis

• Recovery Voltage Test

• Sweep Frequency Response Analysis

• Surge Comparison Test

• Partial Discharge Test (On-line:

Acoustic Emission Technique)

02 • Generators / Large motors

• Stator

• Rotor

• Dielectric loss angle at 50 Hz

• Capacitance at 50 Hz

• Electromagnetic Core Imperfection

Detector (ELCID) Test

• Partial Discharge Test

• DC Leakage current Test

• Polarization Index Test

• Conductor resistance Test

• Surge Comparison Test

• Automatic Wedge mapping Test


• Recurring Surge Oscillogram (RSO

Test)

• Conductor Resistance Test

• Field Impedance test

• Pole Drop Test

03 • Power cables • Frequency domain analysis



• VLF (0.1 Hz) tan delta test

• DC Leakage current test

• Partial Discharge incipient fault

detecting and locating system at VLF

(0.1Hz)

04 • CVTs • Dielectric loss angle at 50 Hz



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05 • PTs • Dielectric loss angle at 50 Hz



Note: These tests are feasible, if and only if,

test tap terminal is provided to PTs.

06 • CTs Dielectric Tests :-




Performance Tests (CT Analyser) :-

• Ratio Error and Phase Displacement

Error

• Knee Point Voltage and Excitation

Current

• Secondary winding resistance

• Turns Ratio

• Instrument Security Factor

• Composite Error Test

07 • Resin Cast CTs

• (Up to 33kV)

• Insulation Resistance / Polarization

Index

• Tan-delta and Capacitance

Power Capacitors Laboratory

Line traps or wave traps are used in almost all EHV Generating stations /

substations and form an integral part in the Power line carrier communication

(PLCC) network. With the advent of numerical relays dependency of

PLCC/DPLCC has increased in EHV line network as dedicated data

/communication along with audio transfers take place between sub-stations. This

has resulted in wide usage of the Line traps.

Temperature rise test is an important type test for line traps. Power Capacitors

Laboratory of CPRI, Bangalore has recently established test facilities for

conducting temperature rise test on line traps as per IEC 60353. The facilities are

being utilized by various manufacturers prior to which they were depending on

overseas Laboratories for the test. Important rating of the line traps tested so far


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include 1250 A, 0.5 mH and 2000 A, 0.5 mH. The facilities will be upgraded to

3150, 0.5 mH and up to 2000, 1 mH, shortly.


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TESTING/EQUIPMENT FACILITY :-

• Parallel Resonance Transformer of Rating: 50/40/30/20 kV ac, 6.8 MVA.

• Parallel Resonance Transformer rating: 70kV ac, 1750KVA.

• HVDC Source of rating: 150 kV 500 mA.

• Discharge current test setup for Series Capacitors.

• 3 Phase Transformer of rating: 975 KVA, 2.5kV ac.

• High Accuracy Capacitance/tan delta bridges: Accuracy: 3.5x10E-5.

• Standard Capacitor :1000 pF, 25 kV.

• Precision Current Comparator up to 5000A.

• Hot Air Oven: 1.8m x 1.8m x 2.0m (WxDxH), Amb to 150°C, Accuracy:

1°C.

• Climatic Chamber: Size- 2.00m x 2.20m x 2.50m (WxDxH),

Temperature: - 70°C to 100°C ± 1°C,

Humidity: 10% to 95% ± 2% RH

• Impulse generator of rating: 500 kV 15 KJ for HV capacitors

• Impulse generator of rating 35kV,100Joules for LV Capacitors.

• 500 MHz Storage oscilloscope.

• Harmonic Generator upto 6kVA,570V,3f, Harmonic generation up to 24th

Harmonic


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With the help of the above facilities, all types of Power Capacitors like All-film

Capacitors, Composite dielectric Capacitors, Metallized film Capacitors etc. can be

tested.

TYPE & RANGE OF CAPACITORS :-

S. No. Product Product Rating Standard

HV Shunt capacitors

(For Routine and Type tests)

3500 kvar, 16 kV, 50 µF IS 13925 Pt 1 –1998,

IEC 60871 Pt 1 – 2005,

IEEE Std. 18 – 2002

HV Shunt capacitors

(For Endurance test)

1000 kvar, 20 kV , 8 µF

1000 kvar, 9 kV, 50 µF

IS 13925 Pt 2-2002

IEC 60871 Pt 2 – 1999

HV Series capacitors

(For Routine and Type tests)

3000 kvar, 20 kV , 50 µF IEC 60143 – 1: 2004

IEC 60143 – 3: 1998

HV Series capacitors

(For Cold duty test)

1000 kvar, 16 kV, 12µF IEC 60143 – 1: 2004

IEC 60143 – 3: 1998

HV Capacitors for surge

Protection.

0.33 µF, 40 kV IS 11548 1986

(Reaffirmed Mar 2006).

LV Motor capacitors 100 x 10 µF, 440 V ac IS 2993 – 1998.

IEC60252 -1-2001

LV fan motor Capacitors 100 x 10 µF, 440 V ac IS 1709 1984

(Reaffirmed Mar 2006 Amendment

No. 2)

LV Capacitors for Lighting 100 x 10 µF, 440 V ac IS 1569 1976

(Reaffirmed 2001)

IEC 61048:1991,

IEC 61049: 1991.

LV Power capacitors of self-

healing type.

150 kvar, 1000 V ac IS 13340:1993, IS 13341:1992

IEC 60831(Pt.1):2004

IEC 60831(Pt.2):1995

LV Shunt capacitors of non self

- healing type.

150 kvar, 1000 V ac IS 13585 – 1:1994

IEC 60931(Pt.1):1996

IEC 60931(Pt.2):1995

IEC 60931(Pt.3):1996


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Capacitors for Power Electronics IEC 61071- 2007

Capacitors for Railway applications – Rolling Stock equipment IEC 61881-1999

MAJOR TESTS :-

All Routine, Type and Special tests as per National & International Standards and

Customer Requirements. Some of the important tests are listed below:

• High Voltage Tests

• Output test / Capacitance & tan delta test

• Short Circuit discharge test

• Test for discharge device

• Thermal stability test

• Sealing test

• Impulse voltage withstand test

• Self healing test on MPP capacitors

• HV test for MPP capacitors

• Charge discharge test on LV capacitors

• Destruction test on LV capacitors

• Discharge current test for Series capacitors

• Disconnecting test on Internal fuses

• Electrical Endurance test for HV capacitors

o Over voltage cycle test

o Ageing test

• Endurance test on LV capacitors: Electrical, Mechanical, Automobile,

Medical, ATMs, etc.

• Temperature rise test on Line Traps up to 2000 Amps

• On-line Partial discharge test employing Acoustic Emission Technique

Heat Run Test Laboratory

TEMPERATURE RISE TEST ON

The Laboratory has facility to carry out Temperature rise test on

Distribution, Transmission & Power equipment and accessories as per relevant

National & International Specifications.

TESTING FACILITY FOR TEMPERATURE RISE TEST

• Current source upto 3200 Amperes , 20 Volts, Three Phase and Neutral

• DC Source 500 Amperes, 200 Volts


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• Temperature Monitoring equipment: Digital & Fiber Optics

• Micro Ohm Meters

• Milli Voltmeter/ Multimeter

S. No. Apparatus Type of Test Standard

01 Distribution Boards Temperature Rise upto 3200 A IEC - 60439

02 Panel Board Temperature Rise upto 3200 A IS – 8623 / IEC 60439

03 Circuit Breaker Temperature Rise upto 3200 A

Resistance Measurement

IEC – 62271-100

04 Isolators Temperature Rise upto 3200 A


IS-9921/ IEC – 62271-200

05 Disconnect Switch-HV Temperature Rise upto


IEC – 60298

06 Current Transformer Temperature Rise upto


IS – 2705/ IEC – 60044

07 Busduct - HT Temperature Rise upto 3200 A IS-8084

08 Busduct - LT Temperature Rise upto 3200 A IS-8623 / IEC – 60439

09 Tap Changer Temperature Rise upto 3200 A IEC – 60214

10 Voltage Transformer Temperature Rise


IS-3156

11 Power connector Temperature Rise upto


IS-5561

12 LV Fuses Temperature Rise upto 3200 A IS-2086

13 AC Metal enclosed Switchgear

Controlgear

Temperature Rise upto


IS-3427

14 HV Circuit Breaker Temperature Rise upto


IS – 13118 / IEC 62271-100

15 LV Circuit Breaker Temperature Rise upto


IS – 13947-2/ IEC 60947-2


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4 Dielectric Materials Division (DMD):-

Liquid Dielectrics Laboratory

The laboratory has sophisticated test facilities like Ultra Performance Liquid

chromatograph, Gas chromatographs with FID,TCD & ECD detectors, Auto

titrator, Automatic Pour Point apparatus, Automatic Breakdown tester, Wavelength

Dispersive X-Ray Fluorescence Spectrophotometer (WDXRF), Megohmmeter,

Moisturemeter, Automatic Viscometers, Abbe Refractometer, Oxidation stability

apparatus, High performance Thin Layer chromatograph, FTIR-ATR, UV-Vis

spectrophotometer and Automatic Flash Point apparatus.

• Testing & certification of new oils for transformers as per IS 335 & IS

12463 for acceptance purposes.

• Testing & certification of new oils for transformers as per IEC 60296- 2003

• Testing & Certification of Reclaimed mineral insulating oils for transformers

as per BS:148-2009

• Testing of Unused synthetic organic esters for electrical purposes as per IEC

61099-2010

• Consultancy services and third party inspection for new oils.

• Compatibility of transformer construction materials with mineral oil as per

ASTM D 3455.

• Evaluation of condition of in-service oils as per IS 1866-2000 for

maintenance purposes.

• Analysis of furans in in-service oils as per IEC 61198 – 1993 for assessing

the condition of solid insulation of transformers.

• Evaluation of internal condition of transformers by Dissolved Gas Analysis

(DGA) as per IS: 9434-1992 & IS 10593-2006

• Mobile test facility for carrying out all tests on in-service oils as per IS: 1866

-2000.

• Undertaking Research Projects on oils for transformers.

Polymer Laboratory’s

The lab is engaged in development of polymeric insulating materials based

on thermoset, thermoplastic and rubber systems.

The laboratory has test facilities like differential scanning calorimeter,

differential thermal analyzer, thermogravimetric analyzer, thermo mechanical

analyzer, thermal conductivity apparatus, Mooney viscometer, Brookfield

viscometer, disc moving remoter, plastic order, environmental stress cracking

apparatus, evolved gas analyzer, gel timer & FTIR spectrometer.


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5 Energy Efficiency & Renewable Energy Division (ERED)

Testing Services :

• Testing of LED lamps as per manufacturers specifications

• Testing of Energy Savers as per manufacturers specifications

• Testing of solar PV lanterns and home lighting systems as per MNRE

specifications

• Laboratory and field testing of street light controllers

• Laboratory and field testing of photovoltaic power inverters (to be

commenced shortly)

• Testing of biomass devices and wood burning stoves

• Testing of power converters including inverters

6 High Power Laboratories (HPL):-

The laboratory comprises of (i) Direct Testing Facility of 2500 MVA

capacity at 36/72.5 kV in three phase and 1400 MVA capacity, upto 245 kV in

single phase for testing of Circuit Breakers and short circuit withstand capability

tests on other apparatus viz., Power Transformers, Wave Traps, Reactors,

Insulators, Lightning Arresters etc., and for short time current test upto 300 kA rms

on Busducts, CTs, Isolators, Panels, etc.,

Synthetic Testing Facility

Synthetic Testing Facility for high power testing of EHV Circuit Breakers upto 63

kA, 245 kV full pole and unit testing of EHV Circuit breakers beyond 245 kV

level.

Features:

Method Parallel Current Injection

Injection Frequency 350 Hz to 1000 Hz

Injection Current 18 kA peak max.

TRV Circuit For two and four parameters as per IEC/Indian

Standards


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Main capacitor bank (C1) 400 kV, 18 µF, 1.44 MJ

TRV capacitor bank (C2 & C3) 2.8 µF/500 kV & 4µF/ 400 kV

Charger ± 20 to ± 440 kV DC

Spark Gap ± 100kV to ± 880 kV

Discharge Resistor 50 ohms

Reactor Banks Bank I - 0.1 to 400 mH, Bank II - 0.1 to 200

mH

Damping Resistor 33 Ohms to 68 K Ohms

High Current Short Circuit Test Facility:-

Direct Testing Facility of 2500 MVA capacity at 36/72.5 kV in three phase

and 1400 MVA capacity, upto 245 kV in single phase for testing of Circuit

Breakers and short circuit withstand capability tests on other apparatus viz., Power

Transformers, Wave Traps, Reactors, Insulators, Lightning Arresters etc., and for

short time current test upto 300 kA rms on Busducts, CTs, Isolators, Panels, etc

Products Tested:

S. No. PRODUCTS STANDARDS

01 High voltage circuit breakers IS 13118, IS 13516, IEC 62271-100,

IEC60427.

02 High Voltage Switches IS 9920,IEC 60265'ANSI/IEEE

C37:30.C37:32.C37:34.

03 High Voltage Fuses IS 9385,IEC60282 (Part1&2)

04 High Voltage Switch Boards IEC 62271-200

05 Terminal Boxes ANSI/IEEE C37.20.7

06 MV Metal enclosed Switchgear IEC-61330

07 Power Transformers IS 2026, IEC 60076


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08 Distribution Transformers IS 11171,IEC60726.

09 Traction Transformers IS1180,IEC 60310

10 Potential Transformers IS 3156,IEC60726,IEC60044-2

ANSI:C57.12.00&90

11 Current Transformers IS 2705,IEC60044-1,BS 7226

12 Lightning Arresters IS3070,IEC60099 (Part 1&4)

13 Insulator Strings Technical Report type 2 IEC 61467

14 AC metal enclosed switch gear &

control gear.

IS3427, IEC62271-200, IEC 60517,

IEC60466,

15 AC Disconnectors & Earth

switches

IS9921,IEC 62271-102

16 Reactors IS 5553,IEC60289.

17 Line traps IS 8793,IEC60353.

18 Bus ducts, Bus bars, Generator

Neutral Bus bar Compartment,

IS 8084,ANSI/IEEE C37.20.2

19 Power connectors, ACSR

conductors,

IS 5561

20 LV Circuit Breaker IS 13947,IEC 60947


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7 High Voltage Division:-

The High Voltage Division comprises of the following laboratories providing

services on dielectric testing and on surge arresters.

1. The EHV test laboratory (Main laboratory).

2. Impulse current test laboratory

3. Pollution laboratory

THE EHV TEST LABORATORY:

The EHV test laboratory consists of an indoor laboratory and an outdoor

laboratory test bay. Indoor laboratory is a high voltage test hall of dimensions

50mX40mX35m housing a 3MV, 150kJ impulse generator, a rain making

equipment and power frequency testing transformers of ratings, a) 150kV,

300kVA. b) 100kV, 100mA and d) 600kV, 2000kVA.

The outdoor test bay consists of a 1800kV, 2000kVA cascade transformer

comprising of three 600kV, 2000kVA transformer units. All these transformer

units and the 600kV, 2000kVA transformer located in the indoor test hall are all

similar for the convenience of inter changeability. The Ac test voltage up to 800kV

from the outdoor bay can be taken into the high voltage test hall by means of a wall

bushing.

Suitable arrangements are available to mount all types of 400kV class

insulator strings on conductors for testing. Material handling facility includes a 24

ton (boom end max), 1 ton (with boom in telescopic mode) mobile crane & 3 ton

fork lift.

Major test, measurement and calibration equipment available are:

o Impulse voltage generator of 3 million volts. 150 kJ

o Power frequency Cascade Transformers setup of 1800kV(ie. 3 nos. of

600 kV each)

o Power frequency Transformers one each of 50 kV & 100 kV, 10 kVA

o 600 kV Partial discharge free coupling capacitor

o 400kV, 2400pF RIV free coupling capacitor

o Digital impulse measuring system of 120 Msamples/sec.

o 1GHz Steep front impulse measuring system.


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o One meter sphere gap capable of measuring of 1MV (Impulse &

Power frequency voltages) as per standards.

o Artificial rain equipment (small & big)

o 50 tonne Universal Testing Machine with digital recording

o Hot & Cold bath for temperature cycle test

o Reference voltage divider 180 kV, AC/DC, 500 kV LI/SI

o Recurrent surge generator.

o Unit Step generator.

o Reference Impulse calibrator.

With the equipment installed at present, it is possible to undertake following

tests on electrical equipment like high MVA power transformers, current

transformers, potential transformers, reactors & line traps, air break switches,

isolators, cables, bushings, insulators etc up to and including 400 kV system.

Types of Tests :

This Laboratory can undertake the following tests as per National & International

Standards:

o Lightning impulse voltage tests up to 2,800 kV (Peak) level.

o Switching Impulse Voltage Dry & Wet Tests up to 1.2 MV peak level.

o Steep front impulse test on ceramic insulators and on polymer

insulators of length up to 500mm.

o Steep front Impulse puncture test for insulators up to & including 33

kV insulators.

o Corona Inception and Extinction Test and RIV measurements up to &

including 400 kV system

o Power frequency voltage Dry & Wet withstand tests up to 1,000 kV

(rms) level

o Porosity test on porcelain insulator fragments.

o Electro-Mechanical test up to 40 tonnes on porcelain insulators.

o Mechanical performance/mechanical test up to 40 tonnes on

polymeric insulators.

o 24 hour mechanical test up to 40 tonnes

o Under oil puncture test for porcelain insulators up to and inclusive of

33kV rating.

o Temperature cycle test on insulators up to & including 110kV rating.

o Ferro Resonance tests on CVT at rated voltage up to 220 kV.

o Surge withstand test.


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o Voltage distribution tests on insulator strings

o DC withstand & flashover tests under dry &wet conditions.

o Performance tests on high voltage dividers as per IEC 60060-2.

o Calibration of digitizers used for impulse measurements as per IEC

1083-1.

2. Impulse Current Laboratory

The Impulse Current Laboratory has been established in 1996 as a

comprehensive test facility for testing of Zinc Oxide elements and ZnO arrester

pro-rated sections up to 11 kV rating as per IEC 60099-4 considering the

importance of ZnO arresters which are being increasingly used by several Utilities.

Its superiority lies in the fact that, it has a unique Computer-controlled Impulse

Current Generator of rating 100 kA, 150 kJ incorporating all conceivable features

in a single consolidated design and is perhaps the only one of its kind in this part of

the world at the time of its commissioning.

The generator has the capacity to generate 8/20 µS lightning impulse current

of 40kA magnitude, 4/10 µS high current impulse of 120kA magnitude, 1/20 µS

steep impulse current of 40kA magnitude, 36/80 µS switching impulse current of

2kA magnitude with a 36/90 µS and long duration rectangular impulse current with

a maximum duration of 4000 µS and a maximum magnitude of 1kA. The generator

has accessories like separate current shunts for measuring each of the current types

mentioned above, wave shaping resistors and inductors. It has a total of 12 stages

with a 2.5 µF capacitor in each stage. An advanced Dr. Strauss make impulse

recording system (TRAS 100-12, 4 channel, 100 MS/s, 12 bit) with advanced

software for recording and analyzing impulse current and voltage and impulse

current superimposed with AC voltage at varying time base, which is a unique

feature required for recording voltages and currents in Operating Duty tests on

arrester nonlinear elements is a part of the Impulse Current laboratory. With this

generator set up all type tests on ZnO arrester blocks up to 6 kV voltage rating as

per National (IS 3070) and International Standards (IEC 60099-4) can be carried

out.


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Types of Tests :

• All type tests on Zno arrester blocks up to 6 kV As per National and International

Standards.

• Residual voltage, Reference Voltage, Power loss, leakage current measurements

on complete assembled arrester.

The Laboratory undertakes the following measurements on complete

arresters to be used in Systems up to 400kV rated voltage.

Lightning and switching impulse Residual Voltage tests on full arrester

up to a maximum of 10 kA. Reference Voltage test on complete arrester. Power

loss and Leakage current measurement. In addition to the tests on gapless arresters

and arrester blocks, the laboratory also undertakes the following works.

Consultancy works on design of grading rings for lightning arresters and insulators

based on electric field computations using Finite Element techniques.

Optimization of minimum clearance requirements for transmission lines

with different types of towers based on computations of electric field, Corona loss,

Radio noise, and audible noise levels.

Pollution Laboratory

The gravity and importance of the problem of insulator pollution is directly

related to the possible effects on the electric power system due to the flashover of

insulators caused by surface pollution. For high degrees of pollution, the reduction

in the withstand characteristics may be high enough as to cause failure of

insulation, even at rated operating voltage. A whole series of faults may occur and

in some cases, even result in a real breakdown of important sections of the

transmission and distribution system. The importance of a correct design for

outdoor insulation in polluted areas becomes evident when a successive re-closing

of the system after a failure caused by pollution flashover fails.

Equipment available :

Although, these problems are old (began at the time of the first electric

installation), their importance have grown steadily in nearly all countries in recent

years, tending to be far more acute than in the past. The principal reasons for this

are shown in the following:


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• Increase in level of industrial pollution and geographical area affected by

pollution due to industries.

• Increased establishment of EHV lines near sea coast.

• Increased adoption of higher transmission system voltage of the level of 765kV

and higher, as the pollution flashover is more critical as the system voltage

increases.

• Increased adoption of HVDC transmission, the pollution flashover is more

pronounced under DC voltage.

Hence, evaluation of pollution performance of insulators of all types in a

test laboratory is essential.

The Pollution Laboratory of High voltage division is a chamber with

dimensions of 12m x 12m x 12m. An array of nozzles confirming to IEC 60507

specifications combined with a salt water pumping and air compressor provide the

required salt fog. The power supply to the chamber is from the first 600kV unit of

the 1800kV cascade transformer. This unit has all the requirements of the test

voltage source required by the standard IEC.60507. Probably this is one of the two

test voltage source in the country strictly meeting such stringent requirement.

Equipment available in Pollution Laboratory:

600 kV, 2000kVA AC voltage source

100 kV, 600kVA AC voltage source

150kV, 1Ampere DC voltage source

Leakage current analyster for ZnO arresters.

Fibre optic based ZnO arrester element column temperature measurement unit.

With these equipment/facilities the Pollution Laboratory can carry out tests on

insulators, insulator assemblies, cable terminations and ZnO surge arresters for

systems up to and including 400 kV.

List of Types of Tests:

1. Pollution test on insulators by salt fog/solid layer method upto 400 kV AC &

150 kV DC

2. SF6 Puncture withstand test facility for DC insulators

3. Thermal runaway tests on insulators

4. Ageing performance of composite insulators

5. Mechanical load test on polymeric insulators

6. Brittle fracture resistance test on composite insulators


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7. Salt fog test on cable terminations

8. Pollution tests on ZnO arreters

This Laboratory can undertake these tests as per National & International

Standards.

Many research activities have been carried out in the Pollution laboratory and

the following are some important ones:

Effect of pollution flashover with respect to diameter of the porcelain shell

1. . Pollution performance of composite insulators

2. Ageing studies on insulator of ceramic & non-ceramic material

3. Pollution tests on ZnO surge arrester

4. Brittle fracture resistance test on composite insulators

5. Hydrophobicity recovery and mechanical load time tests for composite

insulators.

6. Development of HV DC insulator profile for maximum pollution withstand

capability

7. Mathematical model of dynamic arc under pollution condition to predict safe

withstand voltage for a given degree of pollution.

8. Pollution mapping along the proposed Chandrapur Phadge ±500kV DC

transmission line to choose suitable line insulators.

HIGH VOLTAGE TEST AND MEASUREMENT EQUIPMENT

In addition to the testing, R & D and consultancy, High voltage division has

developed may essential test and measurement equipment indigenously for its own

use and for use of industry

Some of them are as follows:

• High Voltage Impulse Measuring Systems

• Spherical Electrode AC Electric Field Meter

• DC Electric Field Meter

• DC Ionic Current Meter

• Combination wave generator

• I.U. Sequencer

• Unbalance recorder


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8.Short Circuit Division (SCD)

Short Circuit Laboratory Test Feasibility :-

S. No. Apparatus Reference to Nature of Test

standards

Range of test

1 Low Voltage

Circuit Breaker

IEC: 60947-2

IA: 13947-2

• Short Circuit

Making and

Breaking

capacity

• Overload

Performance

Short-time

current

• Short-time

current

• Electrical

Endurance

• AC 3 Phase - up

to 50 kA upto

456V up to 20 kA

upto 800 DC upto

30kA/400V

• AC upto 4/2 kA.

rms@415/800V

DC upto 5kA

.dc/800 V

• AC- upto 50 kA.

rms for 1.0 sec &

upto 30kA.rms for

3.0 secs DC upto

30kA.dc for 3.0

secs.

• AC upto 800

A.rms/460V

• DC upto 600A &

upto 600V

2 High Voltage Circuit

Breaker

IEC : 62271

IS:13118

Short-time current AC- upto 50kA.rms for

1.0 sec.& upto 30 kA.rms

for 3.0 secs.

3 Low Voltage

Fuses [HBC/ HRC,

Miniature]

IE : 60269

IS:13703

Short Circuit

Breaking capacity

50 kA upto 415V

20 kA upto 800V

4 Circuit Breaker

for Household

application

IEC : 60898

IS : 8828

Short Circuit capacity

All Type & Routine

test

AC 3 phase upto 25 kA /

456V upto 20 kA / 800v

DC upto 30kA / 600 V

5 Distribution

Transformer

IEC : 60076

IEC : 60726

IS : 202

IS : 11171

Short Circuit

[Dynamic & Thermal

ability to withstand]

• All Type &

• Routine test

• Upto 11kV Class Upto

500kVA rating


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6 Low Voltage Switches

Switch Fuse

Combination units with

HBC & Rewirable

fuses.

IEC : 60947-3

IS : 13947-3

• Rated fused

short Short-

circuit current

• Rated making

& breaking

capacity,

• Short-time

current

Electrical

Endurance

• Other Types

tests

• AC 3 Phase upto

50kA / 456V upto

20kA upto 800V

DC upto

30kA/600V

• AC upto 4/2

kA.rms@415/800

V DC upto

3kA.dc/800V

• AC upto

50kA.rms for 1.0

sec upto 30kA.dc

for 3.0 secs. DC

upto 30kA.dc for

3.0 secs.

• AC upto

800A.rms/600V

DC upto 600A

/600V

7 Low Voltage IEC

Contractors/ Motor

Starters

IEC : 60947-

4-1 IS :

13947-4-1 UL

: 508 C : 22.2

• Rated making

& breaking

capacity,

• Short-time

current

• Electrical

Endurance

• All other Type

& Routine test

• AC upto 4/2

kA.rms@415/800

V

DC upto

5kA.dc/600 V

• AC - upto

50kA.rms for 1.0

sec.& upto

30kA.rms for 3.0

secs. DC upto

30kA.dc for 3.0

secs.

• AC upto

800A.rms/600 V

DC upto 600A /

600V

8 Residual Current-

operated

IEC : 61008

IS : 12640

IEC : 61009

All Type & Routine

tests for AC type

upto 1o kA rms

9 Low Voltage

Switchboard, Panel,

Motor- Control Centre

system, Distin.-

IEC : 60439

IS : 8623

IS : 5039

Short-time current AC 3 phase upto

50kA.rms for 1.0 sec. &

upto 30kA.rms for 3.0

secs. AC 1 phase upto


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boards/pillars 35kA.rms for 1.0sec. DC


sec.

10 Reactor/ Line Traps

Power Connectors

Cable-

IEC : 60289

IS : 5553

IEC : 60353

IS : 5561

IS : 13573

Short-time current AC 3 phase upto 50

kA.rms for 1 sec.& upto

30kA.rms for 3.0 secs.

AC 3 phase upto 50

kA.rms for 1 sec.& upto

30kA.rms for 3.0 secs.

11 Current

Transformers

Voltage Transformers

IEC : 60044

IS : 2705

BS : 7626

IEC : 60186

IS : 3156

Short-time current

accuracy tests, all

other type and routine

tests.

Accuracy Test

AC 1 phase upto 35

kA.rms for 1.0 sec. &


secs.

upto 11 kV

12 Energy Meters IEC : 62052-11

62053-11

IS : 13779

14697,13010,

2675, 13020

Short-time over

current

upto 10 kA

13 HV Switchboard IEC : 60694

Panel

IS : 3427

Short-time current

IEC : 62271-200

AC 3 phase upto 50

kA.rms for 1.0 sec. &

upto 30 kA.rms for 3.0

secs.

DC upto 30kA.dc for 3.0

secs.

14 HV

Disconnector/Isolators

& Earth switch, HV

Busduct

IS : 12729

IEC : 62271-

102

IS : 9921

IS : 8084

Short-time current

DC

AC 3 phase upto

50kA.rms for 1.0 sec.

102 & upto 30kA.rms for

3.0 secs.

DC upto 30kA.dc for 3.0

secs.


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Field Testing and Measurement

The Short Circuit Laboratory is extensively used by the electrical industry and

power utilities for testing, performance evaluation and certification of a large

number of electrical equipment. The facility is also being used by the

manufacturers for indigenous low voltage switchgear and control gear

development.

The laboratory also undertakes the following measurement at site :-

S. No. Type of Test/ Measurement Type of

Equipment

Remarks

1 Ratio error and Phase angle

displacement, Turns Ratio, Composite

error, Winding resistance Exciting

current

Current

Transformer

50 ppm standard CT

2 Turns Ratio Voltage

Transformers

3 No-load loss, Load loss, Turns Ratio,

Winding resistance

Distribution

Transformers

These measurements can be

performed at available power

supply frequency.

Supplementary Test Facility :-

The laboratory has supplementary test facility to carryout tests, pre & post

short-circuit tests, for the acceptance criteria. It is also equipped for other tests like

temperature-rise test (up to 400A, 3 phase and 800A single phase), Electrical

endurance test (up to 630 A, 436 V and up to 400A 690V) & Mechanical

endurance test and some environmental tests (with climatic chambers up to 2.25

cubic meter capacity, from -400C to +1500C temperature ranges & humidity

control of 40% to 98%). as per IS:9000. High voltage power frequency tests up to

100kV for 1min. & induced over-voltage tests up to 1000V @ 400Hz are possible

to conduct at the supplementary tests laboratory. An impulse voltage generator (0-

35 kV, 1.2/50 µs) with the necessary measuring, recording systems are also

available in the laboratory to perform test as per IEC 60060, IEC 61180 & IS 2071.

Surge immunity facility is available to test LV equipment up to 3300A@8/20µs &


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impulse voltage up to [email protected]/50µs as per IEC 61000-4-12. 18 19 Glow-wire

tests (up to 9600C) and Ball Pressure tests can be done as per IEC 60695 & IS

11000.

Another ON-LINE testing set up is available for electrical endurance tests with two

additional transformers of 500 and 1000kVA ratings.


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9 CPRI Organization Chart:-


30

10. Bibliography:-

� CPRI Manual � www.cpri.in

Central power research institute report

Engineering

Transcript of Central power research institute report