Transmission losses based MW contingency ranking

Contingency ranking and selection is an indispensable tool for static security analysis. Several performance indices suffer either from misranking or computational inefficiencies. This paper presents a new performance index for MW line flow contingency selection and ranking. The proposed index is derived from real power transmission losses. It is a quadratic function of bus voltage angles and can easily be calculated from real power flows or DC load flow. It improves both the selectivity and the ranking of second order performance index without excessive computational effort. The proposed method is tested on IEEE 24-bus reliability test system and IEEE 30-bus test system. The results are compared with those of the conventional second order performance index and of the tenth order reference performance index from the point of ranking and selectivity.