雷电冲击电压对配电一二次融合成套设备测量准确度的影响

Impact of lightning impulse voltage on measuring accuracy of primary and secondary integration-set of distribution equipment

为解决一二次融合成套开关设备中二次设备受电磁干扰影响所导致的准确度问题,设计了一套抗干扰测量系统,并基于雷电冲击电压试验电路和抗干扰测量系统对配电网一二次融合成套开关设备测量准确度进行雷电冲击电压干扰测试,采集电压波形并进行时频域分析,得到导致其测量准确度下降的原因。提出在馈线终端采集单元基准端加保护器件和互感器二次输出端加滤波装置这2种防护方案,并对方案的效果进行理论分析和试验验证。结果表明,雷电冲击电压将通过互感器传至二次设备,使得互感器二次侧产生较高的耦合电压,其试验实测幅值达几千伏,频率在几MHz至30 MHz之间,对互感器的准确度影响较大;通过在互感器二次出线端口增加高频滤波装置能有效降低耦合电压,干扰信号强度降低为原来的20%左右,比差和相差降低为原来的40%左右。

In order to solve the reliability problem caused by the electromagnetic interference of the secondary equipment in PSIDE(Primary and Secondary Integration-set of Distribution Equipment),an anti-interference measuring system is designed. Based on the lightning impulse voltage test circuit and the anti-interference measuring system,the lightning impulse voltage interference test of the PSIDE is conducted,and the reason of the decline of its measurement accuracy is obtained by time-frequency domain analysis of the transformer voltage waveform. Two protection schemes are proposed. One is adding protection device in the feeder terminal reference unit and the other is adding filter device at the secondary output end of the transformer. The effect of the protection schemes are analyzed and tested. The results show that lightning impulse voltage is transmitted to the secondary equipment through transformer,which results in high coupling voltage at the secondary side of transformer. The peak value of the coupling voltage is up to several kilovolts while the frequency is arranged from several MHz to 30 MHz,which has a great impact on the accuracy of transformer. By adding high frequency filter device in outlet terminal of the secondary side of transformer,the peak value of the coupling voltage is effectively reduced,the interference signal intensity is reduced to 20% of the original value and the phase and ratio differences of the transformer are reduced to 40% of the original values.