基于R-L模型误差的自适应距离保护

为了描述R-L模型的准确性,提出了R-L模型误差的概念.仿真显示,R-L模型误差与测量电抗误差有明确的关系.目前基于R-L模型算法的距离保护一般采用反时限动作特性,针对其保护范围的开放很保守、不利于中远端故障快速切除的缺陷,提出了基于R-L模型误差的自适应距离保护.故障后,实时计算R-L模型误差,并根据R-L模型误差与测量电抗误差的关系自适应地调整电抗值.仿真结果表明,所提出的自适应方案能有效防止暂态超越,并能显著提高末端故障时的动作速度,整体性能较反时限动作特性距离保护有了很大提高.

Adaptive Distance Protection Based on R-L Model Error

A new concept called R-L model error is proposed, which can describe the accuracy of the R-L model. Simulation results show that there is a definite relationship between R-L model error and measure reactance error. The inverse-time characteristic used in distance protection based on differential equation algorithm has some defects such as conservative protection range and long time delay when the fault is at the end of the protection line. An adaptive distance protection scheme based on R-L model error is proposed to overcome the defects mentioned above. When fault occurs, zone I distance relay calculates the R-L model error in real-time and then modifies the calculation result of measure reactance adaptively according to the relationship between R-L model error and measure reactance error. Simulation results show that this new distance protection scheme can prevent transient overreach and operate rapidly even the fault is at the end of the protection line. The whole performance is enhanced greatly compared with inverse-time characteristic adopted distance protection scheme.