Principles of using Split Core Current Transformers

1. Select the appropriate transformation ratio according to the measured current, otherwise the error will increase. At the same time, one end of the secondary side must be grounded to prevent the high voltage on the primary side from entering the secondary low voltage side once the insulation is damaged, causing personal and equipment accidents.

2. The wiring of the transformer should follow the series connection principle: that is, the primary winding should be connected in series with the circuit under test, and the secondary winding should be connected in series with all instrument loads.

3. For the installation site of Split Core Current Transformers for protection, it should be set according to the non-protection zone of the main protection device as far as possible. For example, if there are two sets of transformers, and the location allows, they should be located on both sides of the circuit breaker, so that the circuit breaker is within the scope of cross protection.

4. In order to meet the needs of measuring instruments, relay protection, circuit breaker failure judgment and fault filtering, etc., all circuits are installed in generators, transformers, outgoing lines, bus sectional circuit breakers, bus circuit breakers, bypass circuit breakers, etc. Split Core Current Transformers with 2 to 8 secondary windings.

5. The secondary side is not allowed to open circuit, because once the circuit is open, the primary side current I1 will all become magnetizing current, causing φm and E2 to increase sharply, resulting in excessive saturation magnetization of the iron core, serious heat generation and even burning of the coil; at the same time, after the magnetic circuit is excessively saturated and magnetized, increase the error.

6. In order to reduce the damage caused by the internal fault of the generator, the Split Core Current Transformers used to automatically adjust the excitation device should be arranged on the outgoing side of the generator stator winding. In order to facilitate analysis and find internal faults before the generator is integrated into the system, the transformer used for measuring instruments should be installed on the neutral side of the generator.

7. In order to prevent the busbar failure caused by bushing flashover, the transformer is usually arranged on the outgoing line or the transformer side of the circuit breaker.