GIS中局部放电UHF信号传播特性研究

Propagation Characteristics of UHF Partial Discharge Signals in GIS

在绝缘子金属法兰浇注孔处放置传感器可以用来接收GIS中辐射出来的电磁波,这是测量局部放电（以下简称局放）信号的一种方法。为研究局放UHF信号在通过绝缘子金属法兰浇注孔时的传播特性,笔者采用时域有限差分法进行了建模分析,研究了UHF信号在通过不同尺寸的金属法兰浇注孔时的场强峰峰值和频谱变化特性;试验研究了高压导体尖刺故障下的UHF信号传播特性,验证了仿真分析的有效性。研究结果表明,沿导杆方向的场强分量远大于另外两个方向的;当绝缘子法兰浇注孔尺寸增大时,从该孔中能辐射出能量更强的信号,而且信号中较低频率（500~900 MHz）的分量占较大比例。

A sensor positioned at the sprue in metal flange of an insulator can receive UHF signals radiated from GIS for analyzing the characteristics of partial discharge. To understand the effects of the sprue size on the propagation of UHF electromagnetic waves,the finite difference time domain（FDTD）method is used for modeling. The characteristics of the time domain and frequency domain parameters of the UHF waves in the middle of the sprues with different sizes are investigated. Moreover,some experiments are conducted to verify the effectiveness of the simulation. The results show that the field strength component along the conductor is much stronger than the components of other two directions, and that the larger the sprue size, the stronger the signals radiating from the sprue,in which low frequency components（500-900 MHz）occupy a large proportion.