A Reliability Evaluation Method of a Protection System using Unavailability Tables and Event Trees

Abstract

A reliability evaluation method of traditional Substation Automation System (SAS) has ever been well developed based on its physical configurations. However, appearance of Intelligent Electronic Devices (IED) based on IEC 61850 requires another type of evaluation with a functional viewpoint, because they integrate control and protection functions. This paper proposes a quantitative reliability evaluation method using an event tree method and unavailability of a module constituting an IED. It also states experimental results of the method applied to two types of protection systems that have a model of double bus bar and two transmission lines, and shows its effectiveness.