Operational Risk Evaluation Model of Distance Protection
Xiaofu Xiong · Dianli xitong zidonghua · 2008
To reveal that the operating mode of power grids and characteristic of impendence relay have significant impact on the reliability of distance protection,an operational risk evaluation model is proposed for distance protection. Firstly,the distributions of action probability and inaction probability on the complex impendence plain are described in detail according to the setting impendence and angle for various impendence relays with circle performance characteristics,and the probability average on the special measuring impendence region is calculated out as the basic reliability parameters. And then,the mis-operation mode and mal-operation mode of operational distance protection are analyzed considering the tripping time,furthermore the calculating formulae of mis-operation and mal-operation probabilities are deduced. Lastly,after analyzing the impact of the mis-operation and mal-operation on the power grids,the risk indexes of loss-of-load are put forward,and the application of this method is clarified using an example.