零序电流互感器 The zero sequence current transformer 零序电流互感器为一种线路故障监测器,一般儿只有一个铁芯与二次绕组,使用时,将一次三芯电缆穿过互感器的铁芯窗孔,二次通过引线接至专用的继电器,再由继电器的输出端接到信号装置或报警系统。在正常情况下，一次回路中三相电流基本平衡，其所产生合成磁通也近于零。在互感器的二次绕组中不感生电流，当一次线路中发生单相接地等故障时，一次回路中产生不平衡电流（意即零序电流），在二次绕组中感生微小的电流使继电器动作，发生信号。这个使继电器动作的电流很小（mA级），称作二次电流或零序电流互感器的灵敏度（也可用一次最小动作电流表示），为主要动作指标。 Zero sequence current transformer is a line fault monitor, as only one core and two windings, when in use, will be the first three core cable through the transformer core fenestrae, two by wire connected to a dedicated relay, and then received by the relay output signal device or alarm system. Under normal conditions, the three-phase current in a primary circuit is basically balanced, and the resulting synthetic flux is near zero. In the two winding transformer in the induced current, when a line single-phase grounding fault, produce unbalanced current in the primary circuit (i.e., zero sequence current) in the two winding induced in small current relay signal. The current of the relay is very small (mA level), which is called the sensitivity of the two current or zero sequence current transformer (which can also be expressed by a minimum action current), which is the main index of action.