| 零序电流 |
| 添加时间：2018/12/29 14:31:24 浏览次数： |
| 不对称运行和单相运行是零序电流产生的主要原因。在三相四线制电路中，三相电流的向量和等于零，即Ia+Ib+Ic=0。如果在三相三线中接入一个电流互感器，这时感应电流为零。 Asymmetric operation and single-phase operation are the main causes of zero-sequence current. In three-phase four-wire circuit, the vector sum of three-phase current equals zero, i.e. Ia+Ib+Ic=0. If a current transformer is connected to the three-phase three-wire, the induced current is zero. 当电路中发生触电或漏电故障时，回路中有漏电电流流过，这时穿过互感器的三相电流相量和不等零，其相量和为：Ia+Ib+Ic=I(漏电电流，即零序电流） 。这样互感器二次线圈中就有一个感应电流，此电流加于检测部分的电子放大电路，与保护区装置预定动作电流值相比较，若大于动作电流，则使灵敏继电器动作，作用于执行元件跳闸。这里所接的互感器称为零序电流互感器，三相电流的相量和不等于零，所产生的电流即为零序电流。 When electric shock or leakage occurs in the circuit, leakage current flows through the circuit. At this time, the three-phase current phases passing through the transformer are unequal zero, and the phases are: Ia+Ib+Ic=I (leakage current, namely zero sequence current). In this way, there is an inductive current in the secondary coil of transformer, which is added to the electronic amplifier circuit of the detection part. Compared with the predetermined action current value of the protective device, if it is larger than the action current, the sensitive relay will act on the actuator to trip. The transformer connected here is called zero-sequence current transformer. The phasor of three-phase current is not equal to zero, and the generated current is zero-sequence current. |
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