针对过渡电阻对距离保护的影响,提出了一种新型自适应距离保护方案。根据单电源和双电源系统中电压与电流的几何分布特性,建立保护安装处与故障点间的电压降落方程,并据此求解自适应整定系数。在此基础上,借助故障电流和测量电流间的相位关系,确定故障点位置,最终构建新型自适应距离保护判据。基于实时数字仿真(RTDS)平台的仿真结果表明,该方法可在线自适应修正保护定值,并具备较强的抗过渡电阻能力,构成简单,易于实现。
In view of the influence of the transition resistance on distance protection,a new adaptive distance protection is proposed.First,according to the fault voltage and current vector distribution in the single-supply and double-supply systems, the voltage drop equation between the fault point and the relay installed location is developed and the adaptive setting coefficient is calculated.On this basis,the fault location is determined by the phase relationship between the fault current and the measured current at the relay.Finally,an adaptive distance protection criterion is developed.Simulation results based on the real time digital simulator(RTDS) show that the method proposed is able to modify the protection setting value adaptively on line,and is immune to transition resistance.Besides,it is simple in formation and easy to implement.