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在超高压(EHV)输电线运行中采用单相重合闸以提高系统的可靠性和稳定性。为利于故障点灭弧,提高单相重合闸的成功率,一般采用并联电抗器加中性点电抗器的接线方式。计算和分析表明:中性点电抗器使断开相处于低电压状态,有利于灭弧,但不利于判断线路的绝缘水平,造成重合于故障线路。在中性点电抗器与地之间装设接地开关,在重合闸之前合上此开关,根据断开相电压值可有效判别线路故障的性质和绝缘水平,可防止重合于故障线路,提高重合闸的成功率。
Single-phase reclosing is used in EHV transmission lines to improve system reliability and stability. In order to facilitate the arc fault point to improve the success rate of single-phase reclosing, the general use of shunt reactor plus neutral reactor wiring. The calculation and analysis show that the neutral reactor makes the disconnection at a low voltage, which is conducive to arc extinguishing, but not conducive to determine the insulation level of the line, resulting in coincidence with the fault line. The grounding switch should be installed between the neutral reactor and the ground. Before the reclosing, the switch should be closed. According to the value of the disconnected phase voltage, the nature and insulation level of the line fault can be effectively discriminated. This can prevent the coincidence with the fault line and improve the coincidence Gate success rate.