Testing of Different Electrical Equipment

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Testing of Current Transfomers

The type tests of current transformers, as per the uploaded document IS 2705 (Part 1): 1992, are as follows:

  1. Short-Time Current Tests (Clause 9.6)
    • Short-time thermal current test.
    • Dynamic current test.
  2. Temperature-Rise Test (Clause 9.7)
  3. Lightning Impulse Voltage Test (Clause 9.8)
    • For current transformers for service in electrically exposed installations.
  4. Switching Impulse Voltage Tests (Clause 9.11)
    • For current transformers of 420 kV and above.
  5. High Voltage Power-Frequency Wet Withstand Voltage Test (Clause 9.9)
    • For outdoor current transformers up to and including 245 kV.
  6. Determination of Errors or Other Characteristics (Clause 9.1.1.f)
    • According to the requirements of the appropriate designation or accuracy class.

The routine tests of current transformers as per the document are:

  1. Verification of terminal marking and polarity: Ensures compliance with specified standards.
  2. Power frequency dry withstand tests on primary windings: Tests the primary windings’ insulation against high voltage.
  3. Power frequency dry withstand tests on secondary windings: Checks the secondary windings’ insulation.
  4. Over-voltage inter-turn test: Evaluates the turn-to-turn insulation of the transformer windings.
  5. Partial discharge tests: Assesses insulation performance under partial discharge conditions (applicable for specific insulation types).
  6. Determination of errors or other characteristics: Verifies performance and accuracy as per the specified designation or accuracy class​.