MODELING CALABAR SUB TRANSMISSION ELECTRICITY NETWORK FOR RELIABILITY STUDIES

ABSTRACT The growing interest in decarbonizing electricity systems together with advances in communication and information technologies that may support the application of demand and generation solutions to solve network problems has initiated reviews in traditional practices and security grid standards in a number of jurisdictions. The key concern is that these historical practices and standards, mostly developed in the 1950‘s, might be inappropriate for the new emerging systems as they may pose entry barriers for both renewable generation and smart grid technologies. This thesis presents a probabilistic cost benefit framework for the development of future efficient operating and design strategies and network security standards enabled by new technologies. By optimally balancing the costs of network constraints with various operational measures composed of preventive and corrective control actions, which course electric power distribution companies are facing with the challenge of providing a reliable, safe and cost-effective electricity to customers. Regular interruptions and outages are experienced in the distribution network leading to increase in the loss of revenue, increase in the cost of electricity supply, maintenance and customer’s dissatisfaction. "This report presents an overview of the Calabar sub-transmission electricity network, which is a critical component of the Nigerian power grid. The network spans across Calabar and surrounding areas, supplying electricity to residential, commercial, and industrial customers. The report highlights the network's topology, including the 33kV and 11kV distribution lines, substations, and transformers. It also discusses the network's performance, including power supply reliability, voltage stability, and energy losses. Additionally, the report identifies key challenges facing the network, such as inadequate infrastructure, high demand, and limited maintenance. Recommendations are provided for upgrading and expanding the network to improve its efficiency, reliability, and sustainability.” This paper presents the Reliability Assessment of 33kV power distribution System of Calabar. The assessment was carried out using outage and interruption data from the year 2017 to 2021 of the eleven 33kV distribution feeders obtained from Transmission Company of Nigeria, Calabar Control Area and Port Harcourt Electricity Distribution Company (PHEDC), Calabar Zone. These data were used as input to the ETAP simulation software to evaluate the reliability indices such as SAIFI, SAIDI, CAIDI, Expected Energy not supplied and Expected Interruption Cost. The results of the assessment shows that the Calabar distribution system SAIFI, SAIDI, CAID Iare higher and is less reliable compared to international standards. The results also shows that Amika and EPZ1 feeder contribute more to the reliability problem of the distribution system. Recommendations to improve the reliability of the distribution system are introduction of distributed generation, static VAR compensators, and replacement of isolators with higher current capacity and construction of parallel feeders.