GIS浇注孔的尺寸与局部放电辐射出的UHF电磁波强度的关系的研究

Study on the Relationship Between the Size of Resin Sprue on GIS and Intensity of UHF Electromagnetic Waves Radiated From Partial Discharge

不同厂家的GIS产品的浇注孔尺寸不一,由于开孔尺寸对局部放电产生的UHF电磁波信号会产生直接影响,造成很难对局部放电严重程度进行量化评估。本文以一252k V的GIS为平台,通过在盆式绝缘子上设置不同尺寸的浇注孔,利用安装在这些浇注孔上的传感器检测由GIS内部尖板局放源发出的电磁波信号,发现辐射出的信号强度随浇注孔长边长度的增加而先增大后减小,在长边长度为75mm时达到最大值。另外的模拟实验——通过脉冲信号源给安装在GIS腔体内的发射天线提供激励的方法来模拟局部放电,再通过同样的传感器检测UHF电磁波信号——也发现同样的结果。利用时域有限差分法,在电磁波仿真软件XFDTD中建立模型的计算结果也证明了这一结果。此结论为GIS浇注孔最优尺寸的选取和外置式UHF传感器的研制提供了参考。

Gas insulated switchgear(GIS) of different manufacturers have different size of resin sprue, and the size of resin sprue has direct effects on the ultra-high-frequency(UHF) electromagnetic waves motivated by partial discharge(PD), which brings about many difficulties in accurate estimate of the severity of PD. On the platform of a 252 k V GIS, we used UHF sensors which were mounted on resin sprues of different size that had been set up in advance to detect electromagnetic wave signals emitted by the needle-plane PD model in GIS and found that with an increase of the length of the long side of the sprue, the signal intensity enhances first and weakens later and get its maximum on 75 mm. Another simulation experiment which used pulse signal generator to provide excitation source for the transmitting antenna in GIS to simulate PD and detected signals in the same way to the former also found the same conclusion. The calculation results in XFDTD--an electromagnetic wave simulation software based on finite difference time domain(FDTD) method also proved the same conclusion. This conclusion offers important references for the options of the best size of resin sprue and development of external UHF sensor.