超高压系统隔离开关操作电磁骚扰的时频特性

Time-frequency Domain Characteristics of Electromagnetic Disturbance in Extra High Voltage System

为了解500kV交流系统隔离开关操作在二次回路产生电磁骚扰的特性,在不同的500kV交流变电站,对隔离开关操作在二次回路中产生的电磁骚扰进行了测量。结果显示:合隔离开关操作的共模骚扰信号是从大到小的衰减振荡波;而分隔离开关操作的共模骚扰信号波形则有完全相反的变化。骚扰信号在不同的变电站和测量点有不同的强度,最大幅值>500V,最长骚扰持续时间>4s。通过对骚扰信号时频特性的分析处理,得到隔离开关操作产生的骚扰为周期信号,其频谱是连续的,骚扰能量集中在0.833和1.67MHz附近2个频率点,系统二次设备设计和工作时应考虑避开;振荡脉冲为非周期函数,频谱连续,最高上限频率约2.5MHz。

In order to know the characteristics of the interference of switch operation in 500kV system,we discussed the electromagnetic disturbance in secondary circuit of isolating switch operation in different 500kV AC substations.The data show that the common signal of isolating switch close is of a damped oscillation wave although the common signal of isolating switch open is completely contrary.The values of the disturbance are different in various substations,the highest value is higher than 500V,and the longest duration is more than 4seconds.The analysis of time-frequency domain shows that the disturbance signal of the isolating switch operation is cycle signal,the spectrum of the signal is continuous,and the power focuses on points at 0.833MHz and 1.67MHz frequency which should be avoided in the design of the secondary system.The maximum frequency of interference is 2.5MHz,and the interference is non-periodic and continuous.