Transmission line fault clearing system reliability assessment: Application of life data analysis with weibull distribution and reliability block diagram

Abstract

High voltage transmission lines are essential assets to electric utility companies as these lines transmit electricity generated by power stations to various regions throughout the country. Being exposed to the surrounding environments, transmission lines are susceptible to atmospheric conditions such as lightning strikes and flora and fauna encroachments. These conditions are called faults. Faults on transmission lines may cause disruption of electricity supply which will affect the overall power system and lead to a wide scale blackout. Therefore, fault clearing system is deployed to minimize the impact of the faults to the power system by disconnecting and isolating the affected transmission lines specifically. One of the main devices in fault clearing system are the protective relays, which serve as the the decision making element for correct protection and fault clearing operations. Without protective relays, fault clearing system is rendered useless. Hence, it is imperative for power utilities, such as Tenaga Nasional Berhad (TNB), which is an electric utility company in Malaysia, to assess the reliability of the protective relays. In this study, a statistical method called Life Data Analysis using Weibull Distribution is applied to assess the reliability of the protective relays. Furthermore, the fault clearing system is modeled using Reliability Block Diagram to simulate the availability of the system and derive reliability indices which will assist TNB in managing the fault clearing system. © 2013 ACADEMY PUBLISHER.