零序电流互感器与普通电流互感器一样都是应用电磁感应原理工作的，但从它们的工作状态来看则有区别。普通电流互感器的一次绕组只与被保护线路的一相连接，并且一次绕组内的电流就是该相的负载电流，二次电流则是一次电流的相应值。而零序电流互感器则不然，它的一次绕组就是被保护线路的三相，在正常工作状态时，由于三相电流的矢量和等于零，铁芯中不会产生磁通，故二次绕组内也不会有感应电流。当被保护线路发生单相接地故障时，三相电流之和不再等于零，它等于每相零序电流的3倍，此时，互感器的铁芯中便产生感应磁通，二次绕组内将有感应电流，从而带动继电器使保护装置动作。 The zero sequence current transformer is the same as the normal current transformer, but it is different from their work state. Average current transformer primary winding and the protected line only one, and in a winding current is the phase of the load current, the secondary current is a current corresponding value. And zero sequence current transformer is not, it's a winding circuit of three phase is to be protected, in normal working state, because of three phase current vector and is equal to zero, won't produce magnetic flux in the core, so there will be no induced current in the secondary winding. When the protected circuit of single-phase earth fault occurs, the sum of three phase current no longer is equal to zero, it is 3 times of zero sequence current of each phase, at this point, the transformer is the core of induced magnetic flux, there will be induced current in the secondary winding, so as to drive the relay protection device. 10kV零序电流互感器通常是用于使继电器动作来指示线路发生接地故障的保护装置。根据规程规定，要求在6~10kV的每路出线上都要装设零序电流互感器，以便利用发生单相接地故障时所产生的零序电流使保护装置动作，发出报警信号。 The 10kV zero sequence current transformer is usually used for the protection of relay actions to indicate ground fault in the line. Requirements according to the relevant provisions of the regulations in 6 ~ 10 kv to furnish on the road for each of the zero sequence current transformer, to take advantage of single-phase earth fault occurs the zero sequence current protection device, signal alarm.