高压线路保护实用选相方案

Utility Fault Phase Selector Scheme for High Voltage Transmission Line Protection

对目前实用的突变量及稳态量选相元件进行了比较,指出了其特点和存在的不足。重点分析了目前选相方案的弱馈侧选相、灵敏度配合以及在系统振荡条件下存在的阻抗识别失配等问题,提出了改进的实用选相方案,采用同一区间的2种阻抗元件互补判别来解决失配问题。EMTP数字仿真计算与动模试验结果表明,新方案在性能上较原有方案有明显改善,尤其对于振荡中选相,可以完全克服阻抗法故障识别中的失配问题,选相结果不受系统振荡的影响。

Currently used fault phase selector components are compared and their characteristics and shortcomings are pointed out. In particular, such problems as the weak power phase selector, sensitivity lit and impedance identification mismatch under the condition of system oscillation are analyzed in detail. An improved fault phase selector scheme is presented, in which the complementary judgment of the two impendence components at the same zone is used to solve the mismatch problem. The results of EMTP digital simulation and dynamic experiment indicate that the new scheme has appreciably improved the capabilities of the original scheme. In particular, for the phase selector under the condition of power swing, the impedance identification mismatch problem can be completely overcome and the fault phase selector result is free from the effect of power swing.