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

25
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

26
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.

27
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 &

28
impulse voltage up to 6.6kV@1.2/50µs 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.

29
9 CPRI Organization Chart:-

30
10. Bibliography:-
CPRI Manual
www.cpri.in

Central power research institute report

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