亚纳秒脉冲用于智能GIS局放IED性能试验的可行性研究

气体绝缘金属封闭开关(GIS)以其占地面积小、可靠性高而在电力系统中得到了广泛的应用,但GIS长期运行过程中不可避免的会产生各种各样的内部绝缘缺陷,并伴随产生局部放电现象,甚至会引起系统故障,因此为保障系统可靠运行,对GIS进行局部放电在线监测具有重要意义。局部放电检测具有电学、声学、化学和光学等多种检测方法,其中电学测量手段主要有脉冲电流法和特高频检测法(ultra-high frequency,UHF)。UHF法测量局部放电辐射出来的电磁波的电场强度,而脉冲电流法测量局部放电引起的视在电荷。UHF法相较于脉冲电流法可提取信号中的特高频成分,具有灵敏度高,可带电监测,智能GIS局放IED(智能电子设备)采用UHF+IED的局放监测方法。文中研究了采用上升沿时间为253.75ps、半高宽约为1.15ns、最大峰值电压为532V(0dB)的亚纳秒脉冲进行智能GIS进行局放IED性能试验的可行性,结果表明:UHF传感器输出信号稳定;局放IED测量结果与亚纳秒脉冲峰值成正相关关系而非线性关系;当亚纳秒脉冲为30~50dB时,IED测量结果分散性较大;因此亚纳秒脉冲信号可用于进行智能GIS局放IED性能试验。

Feasilibility Study on Partial Discharge IED Performance Test of Intelligent GIS with Sub-nanosecond Pulse

Gas-insulated metal-enclosed switches(GIS)have been widely used in power system due to their small floor area and high reliability.However,in the long-term operation of GIS,various internal insulation defects are inevitably generated and partial discharge phenomenon may occur concomitantly,which may even cause system failure.Therefore,in order to ensure the reliable operation of the system,it is of great significance to perform partial dis-charge on-line monitoring of GIS.Partial discharge detection has various detection methods such as electrical,acoustical,chemical and optical.Among them,electrical measurement methods mainly include pulse current method and ultra-high frequency(UHF)method.UHF method measures the electric field strength of electromagnetic waves emitted by partial discharge,while the pulse current method measures the apparent charge caused by partial discharge.The UHF method can extract the UHF components in the signal compared with the pulse current method,which has high sensitivity and can be monitored on-line.The intelligent GIS PD IED(intelligent electronic device)adopts the UHF+IED partial discharge monitoring method.In this paper,the feasilibility is studied that the sub-nanosecond pulse with a rising edge time of 253.75 ps,the FWHM is about 1.15 ns and a maximum peak voltage of 532 V(0 dB)is used to test the IED performance of the intelligent GIS.The results show that the output signal of UHF sensor is steady,IED displays positively correlation with the peak value of the sub-nanosecond pulse rather than a linear relationship,when the sub-nanosecond pulse is 30~50 dB,the results of IED are highly dispersed,so the sub-nanosecond pulse can be used to test the partial discharge IED performance test of intelligent GIS.