Relay Testing Laboratory

CPRI has established comprehensive test facility for Power System Protection Relays/Intelligent Electronic Devices (IEDs). The Relay Testing Laboratory is equipped with Computerised Relay test system for carrying out functional testing for checking accuracy and operating characteristics. Additional software is available for Dynamic/ Transient testing and import of fault data from EMTP simulation & Digital Fault Recorder is also possible. Specialised software is also available for GPS synchronised End-To-End testing of Distance Protection Schemes.

Power System Protection Relay is an intelligent electronic device nowadays, which maintains the power system reliability and gives an output when abnormal condition occurs in the power system resulting in maintain the security of the system. The basic objective of the protection relay is to isolate the faulty section in a power system as quickly as possible so that rest of the system functions normally. It is very much necessary to ascertain Reliability-Security and Dependability, Selectivity, Sensitivity, Speed and the cost of relays.

Various Functional testing are recommended in National (IS: 3231 series) and International Standards (IEC: 60255 series) to check the behaviour of the Protection Relay as required in the field condition. During Functional testing, protection relays/intelligent electronic devices are made to undergo simulated field conditions to check its performance. The relevant National/International standards recommend many tests to ascertain the relays effectiveness to perform its intended function.

Electromechanical, Static, Digital and Numerical protection relays/Intelligent Electronic Devices can be tested at this laboratory. The laboratory is accredited by NABL and conforms to ISO/IEC 17025:2017 requirements. The standards followed for type tests are IS: 3231 series and IEC: 60255 series. All types of Protection Relays/IEDs like Distance, Differential, Directional, Overcurrent, Earth fault, Frequency, Synchronising & Power relays etc. can be tested. Some of the special tests recommended for Numerical protection relays/IEDs like tests with Transient waveforms and harmonic waveforms can also be tested.

  • Facility is extended for Developmental testing.
  • CPRI undertakes Protection relay testing at site.
  • CPRI also undertakes GPS Synchronised End-To-End testing of Distance Protection Schemes for 220 kV feeders and 400 kV feeders


The Relay Testing Laboratory at Power Systems Division has comprehensive test facility for Power system protection relays/IEDs. The Laboratory is equipped with sophisticated Computerized Relay Testing Systems for testing of all kinds of Power System Protection Relays/IEDS for all its characteristics/functions meeting its accuracy requirements. Additionally, software is available for testing of the Protection relays/IEDs under Dynamic/Transient conditions of the system, by importing fault data from EMTP software simulation or from Digital Fault Recorder (DFR). Electromechanical, Static, Digital and Numerical Protection relays/IEDs can be tested in the RTL. The laboratory is accredited by NABL and conforms to ISO/IEC 17025:2017 requirements.

Type Testing of Protection Relays/Intelligent Electronic Devices (IEDs)
Tests are conducted on Power system protection relays used to protect Generator, Transformer,
Bus bar, Transmission line, Reactor, Motor, Capacitor bank etc., in accordance with IEC: 60255 Standard series and IS: 3231 Standard series. Electronic timers are tested as per IS: 5834 standard series. Some of the special tests recommended for Numerical relays like PSB, SOTF and tests with Transient waveforms & Harmonic waveforms are also carried out.

Protection Relay/IED Test Systems

The Relay Testing Laboratory is equipped with the following Computerized Relay Test Systems.
Apart from testing at laboratory, following services are also provided:

Field Testing
Field testing of protection relays/Intelligent Electronic Devices (IEDs) is carried out at the place of installation to check the continued health of the relays deployed in a plant. Field testing have been done for Major power stations, Port trust and Industries like M/s GNDTP-Bathinda, M/s IP-New Delhi, M/s NMPT-Mangalore, M/s HTPS-Kasimpur, M/s VPT-Vizag, M/s BTPS-Bhusawal, M/s PTPS-Panipat, and M/s Ranbaxy Laboratories Lab, Mohali, M/s SgTPP, West Bengal.

Third Party Inspection
The Relay testing lab undertakes pre-dispatch Third Party Inspection (TPI) on Relay/IED and Control panel on behalf of a buyer. The inspection is done at relay manufacturer’s works for M/s HVPNL, Panchkula, M/s RRVPNL, Jaipur and M/s Jammu and Kashmir Power Development-Jammu.

Developmental Assistance
The Relay testing/IED testing facility and assistance is also offered for developmental works as a measure to help the manufacturer to improve and ensure their specified functions before arriving at their final product.

GPS Synchronised End-To-End testing of Distance Protection Schemes
Services are also provided for GPS Synchronised End-To-End testing of Distance Protection Schemes for 220 kV feeder and 400 kV feeders.

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The Head of the Division
Power Systems Division (PSD) 
Central Power Research Institute 

Tel.: + 91 80 2207 2452
 Email: amitjain[at]cpri[dot]in 

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Contact Details

Dr Amit Jain 
Joint Director & HoD
Power Systems Division 
Phone : + 91 80 22072452 
E-Mail :
Mobile: + 91 9902990967