辐射电场特征能量提取法在评估GIS状态中的应用研究

Research on extraction of characteristic energy of radiated E-field method in evaluating GIS status

气体绝缘变电站(Gas Insulated Substation,GIS)内的隔离开关(Disconnecting Switch,DS)或者断路器(Circuit Breaker,CB)的动作会在GIS外部产生强烈的辐射电磁场环境。为了通过此测得的辐射场特征参数评估GIS的健康状态,特提出利用小波包分解提取辐射电场信号特征频段能量的方法。采用bior5.5小波基函数,分别对GIS处于健康状态与GIS中CB内出现绝缘故障两种情况下CB关合动作所产生的辐射电场信号进行4层小波包分解,从而提取不同频段的归一化能量,发现31.25 MHz以下的频段为此GIS因CB动作所产生辐射电场信号的特征频段。经推广,通过对比任意一次CB动作后辐射电场在特征频段的能量与GIS正常运行状态下典型辐射电场的特征频段的能量,可以诊断CB的绝缘故障,评估GIS的健康状态。

Switching operations of a disconnecting switch （DS） or a circuit breaker （CB） in a gas insulated substation （GIS） can stimulate outside GIS strong radiated electromagnetic fields. In order to assess the health status of GIS through its measured characteristic parameters, a method of extracting the characteristic frequency-band energy of the electric field （E-field） based on wavelet packet analysis is proposed. The radiated E-field signals of CB in good condition and those of CB in which insulation fault happens are separately decomposed into 4 layers by using the biorS. 5 wavelet basis function, and the normalized energies of different frequency bands are extracted ; then, it＇ s found that the frequency band below 31.25 MHz is the characteristic frequency band of radiated E-field. By comparing the energies in the characteristic frequency bands after a random CB operation with that of the typical radiated E-field obtained when GIS totally is in good condition, insulation faults of CB can be detected and the operating state of GIS could be evaluated.