基于容性设备接地电流的金属氧化物避雷器阻性电流现场检测方法

On-Site Detection Method for Resistive Current of Metal-Oxide Surge Arrester Based on Ground Current of Capacitive Equipment

现场检测避雷器阻性电流使用的方法分为检修电源法、感应板法、PT二次法。每种测试方法均有各自局限性。当前比较常用的方法是PT二次法,由于需要频繁操作PT二次端子,存在电网短路隐患。因此,提出了一种采用容性设备接地电流作为参考信号的测试方法,测量时无需接触任何参考电压端子,利用容性设备接地电流作为参考信号间接获取避雷器运行电压相位,进而计算得出避雷器阻性电流。通过对PT角差和电流互感器介质损耗角的对比分析以及现场检测验证了该方法的准确性。

The on-site methods to detect the resistive current of metal oxide surge arresters are divided into three types: the method of using power supply, the method of using induction board and the method of PT secondary terminal. Each one has its own limitations. The method of PT secondary terminal is commonly used. Since the PT secondary terminals need to be operated frequently, there is a hidden risk of short circuit in the power grid. In response to this problem, a test method using ground current of capacitive equipment as reference signal is proposed. Resistive current can be calculated based on voltage phase of surge arresters which is indirectly obtained by taking ground current of capacitive equipment as a reference signal without touching any reference voltage terminals during measurement. The accuracy of the method is verified by comparative analysis on the angle difference of PT and the CT dielectric loss angle as well as the on-site inspection.