带并联电抗器的超高压输电线路单相故障识别

Identification of Single-phase Fault for UHV Transmission Lines with Shunt Reactor

超高压输电线路发生瞬时性故障时,伴随着二次电弧拉伸故障相电压幅值逐渐上升;永久性故障时,故障相电压在断路器跳闸后幅值迅速下降并最终保持在一恒定值。为分析瞬时故障时电弧特性,利用ATP/EMTP建立一、二次电弧模型。根据故障相电压幅值变化趋势,计算故障相电压包络的差分在固定时间窗内的能量值,得出永久性故障与瞬时性故障时,能量值表现出明显的差异。因此提出以故障相电压包络的差分在连续时间窗内的能量值与首次时间窗内的能量比的均值作为故障性质识别的判据。大量仿真验证了该判据准确可靠,适用于带并联电抗器的超高压输电线路。

Alongside the stretching of seeondary arc, the fault phase voltage amplitude increases gradually in the pres- ence of transient faults occuring on the ultra high voltage （UHV） transmission lines. However, in the case of permanent faults, the fault phase voltage amplitude decrease and stays at a stable value finally after the circuit breaker trips. To an- alyze the arc characteristics in the case of transient fault, the models of primary and seeomlary are are set up using ATP/ EMTP. According to the variation of fault phase voltage, the energy value of difference of fault phase voltage envelope in fixed time window is calculated. The energy value of permanent faults is significantly different from that of transient faults, so the mean of the ratio of the energy value in continuous fixed time window to that in the first time window is tak- en as the criteria to identity the faults. A large number of simulations verify the reliability and accuracy of the proposed criteria, which is applicable to UHV transmission lines with shunt reactor.