Pertinent factors in the adequacy evaluation of an overall electric power system

Reliability evaluation of generating facilities, composite generation and transmission systems, and of distribution systems, are usually conducted independently, and the reliability indices obtained for each assessment are used to make decisions on the facilities concerned. These assessments often assume the other parts of the system to be fully reliable and capable of performing their intended function. This form of analysis therefore gives an optimistic appraisal of the overall system behaviour. The paper considers the influence of element outages in all parts of an electric power system in order to obtain a more practical appraisal of the overall system indices. The relative contributions to the system indices of composite generation and transmission failures and distribution zone failures are also assessed. In particular, the impact on the system performance indices of pertinent factors such as load curtailment philosophy, contingency level, terminal station outages, additional generation and/or transmission and/or distribution facilities etc., are evaluated. The concepts associated with overall electric power system adequacy assessment are illustrated by application to a comprehensive test system