Category: Testing and Maintenance of Protective Gear

Potential Transformer Tests

Potential Transformer Tests: The three Potential Transformer Tests are namely, Polarity check, Ratio check and Phasing check. Polarity check: Polarity check in Potential Transformer Tests is performed in the same way as that for a CT. If the PT is of the capacitor type then the polarity of the transformer at the bottom of the […]

Current Transformer Tests

Current Transformer Tests: Current Transformer Tests are generally mounted in the switchgear when it is delivered to site and may not be easily accessible. The normal tests which are carried out can easily be performed with the CTs mounted in the switchgear. These tests are: Polarity Check, Ratio Check and Magnetization Curve. Polarity Check: This […]

General Methods of Testing Protective Gear

General Methods of Testing Protective Gear: The General Methods of Testing Protective Gear are namely, Primary Injection, Secondary Injection, Measurement of Time, Primary Injection: These tests are limited by the manner in which current can be passed through the primary winding of the current transformers of the protective gear under test. Generally it is possible […]

Heavy Current Test Plant

Heavy Current Test Plant: Heavy Current Test Plant – Simulating the exact fault conditions as would occur in practice is a difficult and a tedious job. The plant for providing the current for these tests as pointed out earlier ought to be of considerable capacity and special design. To ensure that the behavior of the […]

Testing Overcurrent Relay

Testing Overcurrent Relay: Test benches are used for proving the design characteristics of relays. These are provided with accurate timing apparatus and calibrated current and voltage supplies. The basic circuit for Testing Overcurrent Relay is shown in Fig. (8.1). The harmonic content in the current wave form is kept to within 2% of the fundamental […]

Classification of Relay Testing

Classification of Relay Testing: Classification of Relay Testing are usually conducted to demonstrate that: the relay will operate correctly to clear a fault; and the relay will remain inoperative on faults outside its specified zone. To ensure correct operation of relay, it is advisable to set up a relay testing programme to suit the system […]