A bulk power system reliability assessment methodology

This paper describes a methodology to evaluate the reliability of bulk power systems. The method encompasses the systematic enumeration of contingencies and the evaluation of their effects on the system over a range of system load levels. Contingencies and electric load states are described with Markov models. Reliability indices are computed using these models. Both adequacy and a simplified security approaches are considered in the effects analysis. The framework is capable of considering full security approach but it is not addressed in this paper. In adequacy approach, an improved system simulation method is used based on the single-phase quadratized power flow. Remedial actions are also applied for the purpose of alleviating abnormal conditions. This approach determines whether the system is adequate of supplying the electric load without operating constraint violations. In the simplified security approach, the immediate response of the system is of interest. The simulation approach consists of an inertial redispatch and operating conditions immediately after the contingency before any controls take effect. The objective is to determine whether cascading failures occur. The proposed methodology has been applied to two reliability test systems