STATIC SECURITY ASSESSMENT OF EEPCO'S INTERCONNECTED TRANSMISSION SYSTEM

Abstract

The interconnected system of EEPCO consists of large interconnected power systems with dispersed and geographically isolated generators and loads connected by long transmission lines. This poses high chances of disturbances and contingencies more ancl more frequently which affected the customers. Following the occurrence ol these disturbances, the power system transmissions arc loaded to their Ii 111 its and the substations voltage deviate from the normal limit range thus making it susceptible to partial or total blackout under minor/major disturbances. In this thesis, a comprehensive assessment of static security problem of Ethiopian Electric power interconnected transmission system has been conducted and enhancing mechanisms have been addressed. The study has employed conventional power llow and contingency analysis for assessing the security status of the system using power world simulator software. A standard N-1 criterion has been used for contingency analysis. which holds that the system must remain functional after one contingency. In accordance with this, transmission lines and transformers overloading, and substation voltage limits deviation have been obtained both in normal operation and tor N- l contingency. linall «, lo mitigate these problems, necessary security enhancement measures have been presented. Consequently, tile problem of transmission l ines and transformer overloading. and bus bars voltage limit deviation from the normal limits (: 1 : 10%) have been completely solved for normal operation condition. These problems have also been reduced dramatically in N-1 contingency analysis of the system.