Risk and reliability analysis of substation automation systems using importance measures

Risk is the possibility that an undesirable event might occur in the future that will result in some negative consequences. Risk analysis of a system is required to protect the system from risky (more failure prone) components. Reliability Importance measures play an important role in ranking the components according to the impact on the system adequate performance. Risk based measures are useful in identifying the weak components and help in improving the reliability of the overall system efficiently. Risk and Reliability of Substation Automation System (SAS) are most important and desirable design considerations. SAS consists of different components and its applications require real time performance. Three substation automation system architectures are considered in this paper. Two important measures Improvement Potential (IP) and Risk Achievement Worth (RAW) are used to prioritize the components in two types of architectures of SAS. System reliability expressions for all architectures are computed with their reliability block diagrams. On the basis of these two IP and RAW measures the components DCP, ESW and NCCS are most important, BCU and EI are least important components from both maintenance and risk point of view.