利用暂态特征的新型小电流接地故障监测系统

介绍一种小电流接地故障监测系统的构成、工作原理及现场应用情况。基于故障产生的暂态零序电压电流在特定频段(SFB)内分量呈容性的关系，利用暂态零序电流幅值比较、极性比较及暂态无功功率方向原理实现故障线路综合选择，并利用瞬时接地故障信息对线路绝缘状态进行监测。该系统结构合理、可适用于配电网自动化系统和变电站自动化系统，检测方法不受消弧线圈、不稳定电弧影响，同时可检测消弧线圈支路接地、网络中存在闭环运行线路等特殊故障。

CHARACTERISTIC TRANSIENT BASED MONITORING SYSTEM FOR EARTH FAULT IN NON-SOLIDLY EARTHED NETWORK

The structure, work principle and field application of a monitoring system for earth fault in non-solidly earthed network are presented. According to the capacitive relationship between transient zero model voltage and current components in a selected frequency band (SFB) produced by earth fault, a faulty feeder is selected using the integration method based on amplitude comparison, polarity comparison, and reactive power direction of transient zero model current in SFB. The insulation condition of feeders can be evaluated by detecting instantaneous earth faults. The system proposed is suitable for the distribution automation system and integrated automation system of substations and the detecting method is free from the Petersen-coil and unstable arc influences and capable of detecting special faults, i. e. fault feeder with Petersen-coil, the network with a closed loop.