摘要
在内置式特高频(ultra-high-frequency,UHF)传感器配置不足的情况下,如何向GIS设备内部注入UHF校验信号是GIS局部放电UHF检测系统灵敏度现场校验中的关键问题之一。文中提出金属法兰孔式UHF校验信号注入方法,并研究其可行性,依据工程电磁兼容原理阐述了电磁波经过小孔后的衰减特性。建立了基于252 kV GIS设备的局部放电UHF信号测试平台,在靠近出线套管的GIS腔体内设置局部放电缺陷,在距离缺陷最近的金属法兰孔处设置发射传感器,在GIS典型部位安装圆盘形传感器,利用其接收局部放电和发射传感器辐射的UHF信号。通过对比局部放电信号和注入信号的频谱分布、衰减特性,分析两者的一致性。研究结果表明,UHF电磁波经过金属法兰孔后的衰减程度随着频率的升高而减小,在600 MHz以下注入信号的能量小于局部放电。在现场校验中应适当提高脉冲源的输出幅值和上升沿时间,使注入信号与局部放电信号的幅值和频谱相当。此研究对于推进GIS局部放电检测系统的现场校验具有重要参考价值。
How to radiate ultra-high-frequency（UHF）verification signal into GIS without internal UHF antenna is one of the key problems in field sensitivity verification for partial discharge detection instrument. To solve this problem, metal flange style UHF verification signal radiation method is suggested, in which UHF signal is radiated into GIS through the hole in the metal flange outside the insulator. Attenuation of the UHF signal passing through the small hole is explained with the theory of engineering electromagnetic compatibility. UHF signal test instruments are built up based on a 252 kV GIS. The consistency of verification signal and partial discharge signal is analyzed by comparing their power spectrums and attenuations. Conclusions are drawn that： 1）the attenuations become smaller with frequency rising; 2）the power spectrum and attenuation of the verification signal are similar with that of the partial discharge signal, and the energy of the verification signal is smaller than that of the partial discharge signal when the frequency is below 600 MHz. The output amplitude and rise time of the pulse should be increased so that the amplitude and spectrum of the injected signal and the paritial discharge could be similar in the on-site verification. This work may be applicable to field sensitivity verification of UHF PD detection instrument installed on GIS.
出处
《高压电器》
CAS
CSCD
北大核心
2015年第5期71-76,共6页
High Voltage Apparatus
关键词
GIS
局部放电
特高频
现场校验
金属法兰孔
GIS
partial discharge
UHF
field verification
small hole in metal flange
