采用超高频法监测变电站设备局放水平及其早期预警

UHF-based Monitoring for Equipment PD Within the Substation and Early Warning

变电站内电气设备存在绝缘缺陷可能在运行时尤其当运行状态或运行环境改变的情况下发生局部放电(PD)从而辐射出超高频(UHF)电磁波到变电站空间中。为研究用UHF法监测变电站电气设备PD,用一套固定天线阵列及其配套设备实现监测整个变电站PD及早期预警的目的,在变电站中心位置安装全向天线传感器组成的固定阵列来接收变电站空间中电气设备因PD辐射出的UHF信号,根据检测到的信号判定PD的发生并找到存在PD的电气设备;以宽频带、高增益、水平面(H面)全向性的盘锥天线为UHF传感器构建了监测系统,在变电站试验中系统检测到了放电信号,成功定位了位于隔离开关处的放电源。现场实测结果表明这是一种具有实用价值的变电站全站PD监测及早期预警方法。

We researched the UHF-based method for PD monitoring of electrical equipment in the substation, which could use a fixed antenna array and relevant corollary equipment to monitor PD for the whole substation and to achieve early warning. Omnidirectional antenna array was placed in the centre of substation to receive UHF signals triggered by faulted equipment in substation space, PD existing in substation could be detected and the electrical equipment with PD could be found according to the measured signals. Thereby, we built a monitoring system with wideband, good gain and horizontal plane omnidirectional disc-cone antenna as UHF sensor, in the substation test, system detected the discharge signals and discharge source in disconnector were located by the signals. The site measurement results prove that this is a useful method for PD monitoring of the whole substation and early warning.