基于强跟踪滤波器的小电流接地系统故障选线

Faulty line selection based on strong tracking filter for non- solid- earthed network

国内配电网大多为小电流接地系统,在发生单相接地故障后快速选出故障线路具有重要意义。本文分析了中性点不接地和经消弧线圈接地系统的零序等效模型,建立了关于零序电流和零序电压的瞬时值微分方程,并将线路对地电容转化为线路等效长度。利用强跟踪滤波器算法对各条出线的线路等效长度进行估计,通过判断各条出线的线路等效长度来进行选线。通过仿真表明,该选线方法用于小电流接地系统准确可靠,不受故障电阻、故障距离、故障初相角的影响;并且具有自举性,可以和馈线保护合为一体,满足自动化要求。

The distribution networks in China are mostly non-solid-earthed networks. It is of great significance to select the fault line quickly after single-phase grounding faults. By analyzing the zero-sequence equivalent model of the neutral point grounding and the arc suppression coil grounded system,the differential equations of instantaneous value about the zero-sequence current and zero-sequence bus voltage was established in this paper. Furthermore,the circuit＇s earth capacitance was transformed into equivalent line length. Then the strong tracking filter algorithm was used to estimate the equivalent length of each line,which could identify the fault line. Simulations verified that this method could be correctly and accurately applied to non-solid-earthed networks regardless of the influence of fault resistance,fault distance or fault initial angle,and it could be combined with feeder protection to meet the requirement for automation.