架空-电缆混合线路自适应故障区段重合闸的研究

For the overhead-cable hybrid lines, it is difficult to determine whether to turn on the reclosing or not during the faults. Aiming at this problem, an adaptive reclosing method is proposed to identify the fault sections. A line trap is installed at the junction of the overhead line section and the cable section. When the hybrid line fails, the protection devices at the both ends of the line collects the three-phase voltage values. The frequency spectrum of line mode voltage is analyzed by the discrete wavelet transformation and the Fourier transformation. Then, the fault section is determined using the differences of the high frequency components of line mode voltage at the both ends of the line respectively, which further helps decide whether to turn on the reclosing or not. The reclosing will be switched on when the overhead line fails, while it will be switched off when the cable line fails. A simulation model for the hybrid line faults is built with the PSCAD. The results show that the fault sections can effectively be identified in the proposed method, which is unaffected by the fault types, the fault locations and the transition resistance.