Low Electrical Power Reliability is a serious problem in our country. System reliability problems are caused by interruptions of power distribution system which leads to damage of electrical and electronics equipment and affecting the production time of the customers. This paper attempts to analyze reliability of existing Nazareth distribution system, identify the problems of low system reliability, and give the solutions to reduce the interruptions and redesign of power distribution system to increase the system reliability. The Reliability Analysis of existing system carried out by Analytical methods and simulation using the data collected from the distribution substation and utility service sectors as input. Distribution reliability indices such as SAIFI, SAIDI and ASAI have been analyzed thoroughly on power distribution system and the analyzed distribution reliability indices values have been compared with standard benchmark values and comparison indicates that Nazareth distribution system is unreliable. To improve the reliability of the network, proper maintenance strategy and redesign of distribution system is necessitated. In this paper redesigning of existing 15kV/2×25MVA power distribution system has been made and replaced by 33kV/5×50MVA one and the result of simulated redesigned distribution system indices of SAIFI in numbers per customer year, SAIDI in hours per customer year and ASAI in % in year improved from 956.33, 923.3, and 89.46% to 2.75, 38.72 and 99.56 respectively. Using Electrical Transient and Analysis Program (ETAP) software, the reliability analysis of the redesigned distribution system and the existing system has been simulated and compared and the result obtained reveals that the reliability of the system is improved and its marginal difference with benchmarked one reduced significantly.Low Electrical Power Reliability is a serious problem in our country. System reliability problems are caused by interruptions of power distribution system which leads to damage of electrical and electronics equipment and affecting the production time of the customers. This paper attempts to analyze reliability of existing Nazareth distribution system, identify the problems of low system reliability, and give the solutions to reduce the interruptions and redesign of power distribution system to increase the system reliability. The Reliability Analysis of existing system carried out by Analytical methods and simulation using the data collected from the distribution substation and utility service sectors as input. Distribution reliability indices such as SAIFI, SAIDI and ASAI have been analyzed thoroughly on power distribution system and the analyzed distribution reliability indices values have been compared with standard benchmark values and comparison indicates that Nazareth distribution system is unreliable. To improve the reliability of the network, proper maintenance strategy and redesign of distribution system is necessitated. In this paper redesigning of existing 15kV/2×25MVA power distribution system has been made and replaced by 33kV/5×50MVA one and the result of simulated redesigned distribution system indices of SAIFI in numbers per customer year, SAIDI in hours per customer year and ASAI in % in year improved from 956.33, 923.3, and 89.46% to 2.75, 38.72 and 99.56 respectively. Using Electrical Transient and Analysis Program (ETAP) software, the reliability analysis of the redesigned distribution system and the existing system has been simulated and compared and the result obtained reveals that the reliability of the system is improved and its marginal difference with benchmarked one reduced significantly.Low Electrical Power Reliability is a serious problem in our country. System reliability problems are caused by interruptions of power distribution system which leads to damage of electrical and electronics equipment and affecting the production time of the customers. This paper attempts to analyze reliability of existing Nazareth distribution system, identify the problems of low system reliability, and give the solutions to reduce the interruptions and redesign of power distribution system to increase the system reliability. The Reliability Analysis of existing system carried out by Analytical methods and simulation using the data collected from the distribution substation and utility service sectors as input. Distribution reliability indices such as SAIFI, SAIDI and ASAI have been analyzed thoroughly on power distribution system and the analyzed distribution reliability indices values have been compared with standard benchmark values and comparison indicates that Nazareth distribution system is unreliable. To improve the reliability of the network, proper maintenance strategy and redesign of distribution system is necessitated. In this paper redesigning of existing 15kV/2×25MVA power distribution system has been made and replaced by 33kV/5×50MVA one and the result of simulated redesigned distribution system indices of SAIFI in numbers per customer year, SAIDI in hours per customer year and ASAI in % in year improved from 956.33, 923.3, and 89.46% to 2.75, 38.72 and 99.56 respectively. Using Electrical Transient and Analysis Program (ETAP) software, the reliability analysis of the redesigned distribution system and the existing system has been simulated and compared and the result obtained reveals that the reliability of the system is improved and its marginal difference with benchmarked one reduced significantly.

Keywords : Distribution System, Reliability Analysis, Reliability indices, Distribution System Design, ETAP.