Composite reliability evaluation of interconnected power systems

A power network can be divided into several subsystems such as generation, transmission and distribution subsystems. The most popular approaches for reliability evaluation, namely contingency enumeration and Monte-Carlo simulations, have been combined in this paper to form a hybrid algorithm for reliability assessment of composite generation and transmission subsystems. The main objective of this hybrid approach is to enumerate transmission outages and then sample generation states, conditioned to each enumerated transmission state, to evaluate the annualized reliability indices of the entire system and different load centers. Within the proposed hybrid algorithm for generation rescheduling, correction of voltage levels or alleviating of component overloading in order to minimize the amount of load curtailment, a linear programming model is implemented. This algorithm has been utilized for assessing the reliability of the Unified Egyptian Power System, Moreover a weak point analysis is carried out to define the different measures to improve the system reliability. These measures include generation capacity addition, increasing transmission capacity or regional interconnection with other utilities.