The primary winding of the current transformer is directly connected in series with the power line. Therefore, the insulation level of the winding must be adapted to the voltage level of the power line. Its capacity can meet the long-term maximum load current of the power supply without causing the temperature of the primary winding to rise or exceed allowance.

 

      Under no circumstances should the secondary winding terminals of the current transformer be opened, otherwise dangerous high voltages will be generated, which may lead to personal and equipment accidents. This is because when the primary winding of the current transformer is disconnected, the primary winding of the transformer All of the currents are excitation currents, which increase the magnetic flux density in the iron core, thereby inducing up to thousands of induced currents. The secondary winding circuit of the current transformer must be grounded. This is to prevent high voltage from appearing in the secondary resistance after the primary winding and the secondary winding breakdown, which may damage the secondary equipment and endanger personal safety. However, the current mutual inductance The secondary circuit of the relay must not be grounded at two points, otherwise the relay protection will fail due to grounding current.