基于故障相暂态信号特征的二维故障选线法

Two-Dimensional Fault Line Detection Based on Transient Signal Features of Fault Phase

中性点非有效接地系统发生单相接地故障时,故障出线故障相与非故障出线故障相的暂态信号在能量集中频段和信号幅值上存在较大差异:前者幅值大、能量集中频段低,而后者特征恰好相反。为此提出一种基于故障相暂态信号能量和重心频率的二维故障选线方法,利用二维选线判据中包含的故障暂态信号在频域的整体分布特征进行选线,二维判据相互补充,大大增加了选线可靠性。该方法同时适用于纯架空线路和存在电缆出线的混合线路网络,在中性点不接地和谐振接地系统中都适用,并且在故障初相角为0以及高阻抗故障时都有效。对不同情况下的实际仿真证明了所提方法的正确性、有效性和适应性。

When single-phase earth fault occurs in neutral non-effectively earthed system, there are remarkable differences between transient signal of faulty phase and that of non-faulty phases in energy-concentrated frequency bands and signal amplitudes, the fault signal of faulty phase possesses high amplitude and the energy is concentered in low frequency band, however for non-fanlty phase the conditions are just the opposite. On this basis a two-dimensional fault line detection method, which was based on the transient signal energy and centroid frequency of faulty phase, was proposed. The overalldistribution characteristic of transient fault signal in frequency domain, which is included in the creteria of two-dimensional fault line detection, was used to detect the faulty line, in view of the fact that the two-dimensional creteria were complementary each other, the reliability of faulty line detection was evidently enhanced. The proposed method was suitable to distribution network only possessing overhead feeders and hybrid distribution network where the cable outlet existed, and was suitable to ungrounded neutral system and resonant earthed neutral system. Besides, the proposed method was effective for both conditions： the initial phase angle was 0~ at the moment the fault occurred and high resistance grounding fault. The correctness, effectiveness and adaptability of the proposed method were verified by simulation results of distribuion network under different fault conditions.