基于分布参数模型的输电线路相间距离保护

摘要

采用分布参数建模,利用保护安装处的测量电压和测量电流计算等效故障点电压,根据保护区外故障时等效故障点电压相量在测量电压和补偿电压相量一侧和保护区内故障时等效故障点电压相量在测量电压和补偿电压相量之间这一故障特征构成判据,提出一种适用于高压/超高压/特高压输电线路的相间距离保护新方法.该方法有良好的耐故障电阻和抗负荷电流影响的能力,具有良好动作灵敏度.该保护原理适用于距离保护I段,具有良好的保护范围.EMTDC仿真结果验证了该保护原理的正确性和有效性.%The line model is built with distributed parameters and the equivalent voltage at fault point is calculated with the voltage and current measured at the point where the protection is installed. It is found that,the phasor of equivalent voltage at fault point is outside the sector between the phase-to-phase voltage phasor and the operation voltage phasor when the fault is beyond the protective zone while it is within the sector when the fault is in the zone, which is taken as the criterion and applied to zone-I of the phase distance protection suitable for HV / EHV /UHV transmission lines. It has excellent operational flexibility and steady protective zone,immune to the influences of fault resistance and load current. Simulative results with EMTDC verify its correctness and validity.