How to Inspect the Secondary Circuit of Split Core Current Transformers
Aug 12, 2026| I. Appearance and Basic Safety Inspection
1. Check that the entire secondary circuit has no easily disconnectable components such as fuses or switches, and that all terminals are securely fastened.
2. Confirm that the secondary conductor cross-sectional area is ≥2.5mm² copper core wire, and that there are no damages, breaks, or loose connections.
3. Verify that the secondary circuit has only one reliable grounding point, that the grounding connection is secure, and that there are no potential risks of multiple grounding points.
II. Continuity and Open Circuit Special Inspection
1. Use a multimeter in continuity mode to test the entire secondary circuit, confirming that there are no open circuit points throughout, thus preventing high voltage generation during operation.
2. After disconnecting the secondary circuit grounding point, test the insulation of the entire circuit to ground. If the insulation is qualified, it verifies that there is only a single grounding point.
3. Check that the spare secondary winding is also reliably short-circuited, and that there are no potential safety hazards of idle open circuits.
III. Wiring Correctness Verification
1. Use the DC method with a dry cell battery to check the polarity, confirming that P1 and S1 are the same terminal, and that the subtractive polarity wiring is correct.
2. When carrying the rated primary current, the deviation between the secondary output current and the theoretical value calculated by the turns ratio is ≤5%, indicating accurate value.
3. In a three-phase scenario, the phase of the secondary current in each phase is normal, with no abnormalities such as zero current or excessive deviation in any phase.
IV. Characteristic and Redundancy Verification
1. Conduct volt-ampere characteristic tests when necessary to identify the core saturation level and determine whether there is an inter-turn short circuit in the secondary winding.
2. Ensure that the secondary circuit identification plates are clear, indicating the route and purpose, to facilitate subsequent maintenance and troubleshooting.
