电流互感器的使用方法 Use of current transformer 　　1、电流互感器极性检查 ： Polarity check of current transformer: 　　电流互感器一次绕组标志为P1、P2，二次绕组标志为S1、S2。若P1、S1是同名端，则这种标志叫减极性。一次电流从P1进，二次电流从S1出。极性检查很简单，除了可以在互感器校验仪上进行检查外，还可以使用直流检查法。[1] The current transformer is marked as P1, P2, and the secondary winding is S1, S2. If P1 and S1 are the same name, this sign is called subpolarity. Once the current flows from P1, the secondary current comes out of S1. The polarity check is simple and can be used in addition to the inspection of the transformer test instrument. [1] 　　2、电流互感器退磁检查 2, current transformer deflux check 　　电流互感器在电流突然下降的情况下，互感器铁芯可能产生剩磁。如电流互感器在大电流情况下突然切断电源、二次绕组突然开路等。互感器铁芯有剩磁，使铁芯磁导率下降，影响互感器性能。长期使用后的互感器都应该退磁。互感器检验前也要退磁。退磁就是通过一次或二次绕组以交变的励磁电流，给铁芯以交变的磁场。从0开始逐渐加大交变的磁场(励磁电流)使铁芯达到饱和状态，然后再慢慢减小励磁电流到零，以消除剩磁。 The current transformer can generate the residual magnetism when the current suddenly drops. If current transformer interrupts power supply in large current situation, the secondary winding suddenly opens. The iron core of the transformer has the residual magnetism, which causes the core permeability to drop, which affects the performance of the transformer. The current transformer should be demagnetize after long term use. Also demagnetization before the test of the transformer. The demagnetization is the magnetic field that is alternating with the alternating current of excitation current, which is alternating with the secondary winding. Starting from 0, the alternating magnetic field (excitation current) gradually increases the core to saturation state, then gradually reduces the excitation current to zero to eliminate the residual magnetism.