Terminal Effects and Protection System Failures in Composite System Reliability Evaluation

This paper considers the effect of terminal station outages on the contingencies that should be studied in composite system reliability evaluation. It describes how these contingencies are affected by the operation and non-operation of the protection breakers in a terminal station. It also describes how the reliability indices of protection systems which contain commonly- shared components, redundancy and diversity can be evaluated using the event tree method and how these indicies are used to determine the associated indices of the contingency. The discussion illustrates that the effect of terminal station outages on the contingencies to be included in a composite system study can be severe and that it c-an be very important to model the protection system in a realistic manner.