The introduction of IEC61850 standards for substation automation requires the specification of the reliability and availability performance parameter. Presently, the methodology to calculate and verify the parameters is not readily available. This paper proposed a methodology to calculate the parameters at device level, bay level and substation level. The paper will propose suitable monitoring and evaluation of those parameters for future improvement.

Abstract

Protection system in a power system domain plays a vital role as watchmen to safe guard power system apparatus in the event of faults. The integrity and effectiveness of these watchmen is heavily dependent on the reliability of the components that makes up the system. One of the main components in a protection system is protective relays that provides decision making element for correct protection and fault clearing operations. Failure of the protection devices may reduce the reliability of the power system protection that will impact the overall performance of the power system. Hence it is imperative for power utilities, such as Tenaga Nasional Berhad (TNB) to assess the reliability of protective relays to assure it will perform its intended function without failure. This paper will discuss the application of reliability block diagram (RBD) to assess the reliability and availability of a typical 132kV transmission overhead line protection system using historical failure data of protective relays.

Active management of complex distribution networks with distributed generation requires state estimation. As complete supervisory control and data acquisition systems are seldom available on 11-kV or lower voltage distribution networks, real-time measurements at remote points on 11-kV distribution networks are expensive. Therefore, the economical selection of a communication system for active management of distribution networks with distributed generation becomes an important issue. This paper presents the investigations into a leased communication system made of public-switched communication network channels for a distribution network state estimation application. It analyzes the effects of a different number of primary channels for real-time measurements on the distribution network state estimation accuracy. The leased communication system availability performance has also been analyzed and used to identify a number of reserve channels required to improve the leased system availability. The overall cost for improving the leased communication system availability has been calculated and compared with both a fiber-optic communication system and a power-line carrier communication system. The results show that the leased communication system is able to provide the lowest overall cost performance for the distribution network state estimation application.Index Terms-Active distribution network management, communication system availability, communication system cost assessment, state estimation.

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