特高压变电站工频电磁场对避雷器在线监测装置测量准确度影响研究

Accuracy examination of linkage current online measurement of surge arresters under power frequency interference of electric field and magnetic field in the ultra-high voltage substations

变电站现场存在各种干扰,可能影响避雷器泄漏电流的测量准确度。在实验室内对避雷器在线监测装置开展试验,施加工频电场/工频磁场干扰并检验测量准确度。在工频电场干扰时,若传感器电流线未采用屏蔽,泄漏电流测量读数会出现较明显的波动。传感器电流线采用屏蔽能够有效抵制工频电场干扰布线方式的改变,也会明显改变避雷器泄漏电流的测量结果。在工频磁场增大的情况下,避雷器泄漏电流的波动范围也会增大。

Various kinds of interference in the ultra-high voltage substations are significantly inferential to the linkage current measurement of surge arresters. In order to check the normal measurement of the linkage online current measurement of surge arresters, both electric field and magnetic field interference at power frequency is proposed in the lab tests. Under the electric field interference, the test results of linkage current are over the error of the nominal value on the plate of the device if the wires of the sensor are not shielded. However, using the shielding can avoid this electric field interference. Moreover, placement of the wires can obviously change the measurement results. Meanwhile, the level of change of the measurement data increases with the electric field interference.