10kV开关柜开断对二次智能设备的电磁干扰

Electromagnetic Interference on Secondary Smart Devices Caused by Breaking 10 kV Switch Cabinet

随着开关柜电压等级的提高，高压部分与低压智能化设备的电磁兼容问题日益突出，断路器开断被认为是中压开关柜中最严重的电磁干扰来源，它可能会造成二次控制设备出现故障，研究开关柜开断对二次智能设备的电磁干扰问题具有重要意义。利用振荡型合成试验回路对10 kV开关柜进行合成开断试验，同时采集了电流互感器输出电流信号，智能操控装置和间隔智能单元输入电流信号。对采集的波形数据进行时频特性分析，得到干扰信号的频带及能量分布情况。结果表明：开关柜开断对电流互感器二次侧、智能操控装置以及间隔智能单元均产生了瞬态电磁干扰，开断燃弧过程的干扰频带主要分布在31.25~62.5 MHz；电弧过零阶段频带主要分布在15.625~31.25 MHz；干扰幅值最大达到正常情况下的4倍。

Along with uprating the voltage class of the switchgear the electromagnetic compatibility （EMC） between the high-voltage components and the low-voltage smart devices becomes increasingly prominent, and the breaking of the circuit breaker inside the medium-voltage switch cabinet is regarded as the source of the most severe electromagnetic interference, because it could lead to the failures in the secondary control devices, therefore it is significant to research the electromagnetic interference on secondary smart devices caused by breaking the switchgear. The oscillation mode of synthetic test circuit is used to perform breaking test of 10kV switch cabinet and the acquisition of the output current signal of CT and the input current signals of smart control devices and bay smart units are carried out simultaneously. The time-frequency analysis on the acquired signals is performed to obtain the frequency band and the energy distribution situation of the interference signals. Test results show that the breaking of the switchgear leads to the transient electromagnetic interferences on CT’s secondary side, smart control devices and bay smart units; the interference frequency band during the breaking and arcing process is mainly within the range from 15.625 MHz to 62.5 MHz; the maximum amplitude of the interference is four times as large as its normal value.