以串联补偿(简称串补)线路的暂态物理模型为基础,基于参数识别原理提出一种适用于串补线路的距离保护方法。该保护利用系统故障时的暂态信息识别串补线路的电感参数来反映故障点到保护安装处距离,克服了串补电容带来的超越问题,并将故障点相对于串补的位置转化为待识别的未知量,实现串补前故障与串补后故障算法上的统一,无需事先识别故障点相对串补的位置,无需与传统保护配合。识别过程仅利用金属氧化物压敏电阻(MOV)导通前一段时间的暂态信息,避开了MOV非线性影响。该保护仅利用单端电气量,无需通信通道,易于实现。算例仿真结果验证了该方法的有效性和适用性。
Based on transient models of series compensated lines and parameter identification principle,a new distance protection method for series compensated lines is proposed.The protection uses transient fault information to calculates the inductance of series compensated lines which can correctly reflect the distance from fault point to relay location,so it can overcome the overreach problem for external faults.Moreover,the fault point relative to series capacitor compensating location is turned to an unknown evaluated variable.The unity of protection algorithm is implemented when faults occur in front of series capacitors or behind them,so there is no need to identify the fault location relative to series capacitors in advance and no need to cooperate with traditional protection.Since only the transient data before mental oxide varistors(MOV) conduction is used for identification process,MOV's nonlinear characteristic needn't to be considered in this method.Because only single terminal electric quantities are used,the protection is easy to be realized without using communication channels.The simulating results show the validity and adaptability of the protection principle proposed.