System and Load Points Reliability Evaluation for Electric Power Systems

-This work deals with the reliability evaluation of a composite electric power system operating economically. The reliability evaluation and the economic dispatch are conducted using the optimal power flow and the probabilistic method. Moreover, a linear programming method with real power variables is employed for the optimal power flow. From power flow solutions, the load demand satisfied and unsatisfied can be calculated. The reliability evaluation in this study includes evaluating the reliability of system and load points. The basic reliability indices are probability of failure and frequency of failure, and those are used to derive many other reliability indices for the system and load points. The investigated reliability indices are not only useful for design of flexible power supply reliability for various customers but also beneficial to long-term system capacity expansion planning of electric power systems. In the solution process, the optimal power flow analysis is first performed over the studied system, then the aforementioned reliability indices are computed based on the results from the optimal power flow analysis. Appropriate load curtailment is performed if the load demand is unable to be fully satisfied. Consequently, a pertinent load shedding strategy is introduced. Finally, the application and effectiveness of the proposed method are demonstrated and verified by an application system.