IMPACT OF LEVEL OF CONTINGENCIES ON WELLBEING STATES OF GENERATING SYSTEM – A PROBABILISTIC AND FUZZY APPROACH

Abstract

The required level of operating reserve to be maintained by an electric power system can be determined by deterministic and probabilistic techniques. The power system parameters such as failure and repair rates used in the probabilistic models basically come from historical operation records, which are necessarily limited and subject to errors. There is considerable data uncertainty that exists in these parameters. This paper presents the application of fuzzy sets, which is recognized as a potential tool to include data uncertainty in normal calculations, for evaluation of spinning reserve is illustrated. In conventional reliability evaluation method, loads are deterministic values. The failure rate of the generating units is represented as triangular fuzzy number. The fuzzy set is used to represent consumer's demand, which is the deterministic load, as fuzzy loads. The concept is extended for evaluating the fuzzy based well-being indices using different criterion for the generating system. The fz-forced outage rate (FOR) and fz-availability of a unit in service are evaluated using fuzzy Sets and fuzzy interval arithmetic to find the fuzzy well-being states, which are designated as healthy, marginal and at risk. The concept is illustrated for a Roy Billinton's Test System (RBTS) and IEEE RTS. Impact of outage level and deterministic criteria is also illustrated. The proposed method can be applied to the operation of deregulated power system in which operating reserve is served as an important issue with respect to stable and reliable operation.