Enhancing Power Reliability through Improved Distribution Substation Design

This dissertation work is a study about “Distribution Substation to Improved the Power Reliability”. The first task of the study is evaluating the reliability of the existing distribution system,calculating the most powerful reliability indices. The standard of other countries. As this study indicates, the existing power distribution system of the city has many problems. The main problems are high level of unreliability, low energy management, poor scheduled maintenance and operation. To address the challenges of the existing distribution system, designing of an improved substation has been proposed as a solution to tackle the problem.

The new design can be considered as a modern distribution substation which includes automatic reclosing systems to minimize the durations of interruptions, remote telemetry units to communicate with the control room and load dispatch center and the grounding grid system for safety of personals and equipment in the substation. The design process starts from forecasting the future load of the substation and includes detail procedure of fault current and voltage drop calculations, selection ofthe major substation equipment, selection of protection devices and the earth mat design.

The study utilized different meteorological and statistical data and software like MS-Excel, AutoCAD, Simulation, design and Optimization Software. The simulation is used to evaluate the designed power distribution substation to ascertain that, it produces the desired reliability improvements. The result of the simulation shows that the designed system can advance the reliability of the overall system by improving the reliability indices values.

Keywords: Power reliability, Distribution substation, Reliability indices, Substation design, Ethiopia