零序电流互感器是一种套在电缆上的CT，它的一次绕组为穿过CT内孔的三相一次导体电缆，它的一次电流是一次三相电流的向量和（在正常、三相平衡时为0），当发生一次系统单相接地时三相平衡关系被打破，这时零序电流互感器的二次就有电流输出，供给保护装置，实现保护和监控。
Zero sequence current transformer is a cable CT, its primary winding for three-phase CT through the inner hole of a conductor cable, a current which is a three-phase current vector and (in normal, the three-phase load balance is 0), when a single-phase grounding system three phase balance relationship is broken, then the zero sequence current transformer is the two time the current output, supply protection, protection and monitoring.
零序电流互感器的一次绝缘就是电缆自身绝缘，所以这种零序电流互感器可以套在任一电压等级的电缆上。
The one time insulation of the zero sequence current transformer is the insulation of the cable itself, so this zero sequence current transformer can be placed on any cable of any voltage level.
这种零序电流互感器主要用在中性点不接地或经消弧线圈接地的系统。
The zero sequence current transformer is mainly used in the system with neutral points ungrounded or grounded by arc suppression coils.