A Reliability Evaluation Model of Percentage Differential Protection Criteria for Transformers
J. S. Kuang · Power System Technology · 2008
By means of probabilistic methods the performance of protection action criteria is researched. On this basis the authors propose an operational reliability evaluation model for protection criteria. Firstly, the authors describe the restraint characteristics of several percentage differential protection criteria and the requirements to sensitivity, and distribution of protection action probability on the differentia quantity and restraint quantity relationship plane;then taking the mean value of action probability within the varying range of differentia quantity and restraint quantity under actual operating mode as the basic reliability parameters, the misoperation reliability and maloperation reliability of protection criteria are deduced;finally, the practicality and effectiveness of the proposed model are illustrated by calculation examples.