输电线路自适应电流纵差保护方案设计

采用单一判据的电流纵差保护无法兼顾超高压线路对灵敏性、速动性和可靠性的要求。对现有判据进行综合分析、取长补短,结合自适应原理,设计了一个总体性能最优的保护方案,即用基于故障分量瞬时值的差动判据反映严重故障;用故障分量相量的差动判据反映轻微故障;用全电流差动保护判据反映转移性和发展性故障;用零序电流差动保护判据反映轻微的高阻接地故障。ATP仿真结果表明,该方案具有良好的反时限特性,切除故障的速度加快,且可以反映高阻接地故障,是一种性能较好的超高压线路电流纵差保护方案。

Scheme of adaptive current longitudinal differential protection for transmission line

Single differential criterion can't satisfy the special requirements of UHV transmission line for sensitivity, speed and reliability of protection. In this paper, an integrated scheme which has the optimum functions is provided based on several different criteria and adaptive principle.The criteria based on instantaneous value of fault component is chosen to protect the serious fault, the criteria based on fault component phasor to protect the slight fault, the criteria of whole-current differential protection to protect converted fault and developed fault, and the criteria of zero-sequence current differential protection to protect high impedance-to-ground fault.The simulation results based on ATP show that the scheme has the inverse time-lag character,and can clear the faults with a higher speed. It proves to be a proper scheme for current longitudinal differential protection of UHV transmission line.