A Study of Development of Protective Relays in Khartoum City Transmission and Distribution (110/33/11KV) /33/11 Substations (110/33/11KV) of National Sudanese Electricity Grid

Abstract

Present power system is a complex network comprising of various power plants interconnected through transmission lines in a grid meeting the growing need of power. With the complexity in network and power distribution, the power system is subjected to constant disturbances created by random load changes, by faults created by random load changes, by faults created by natural causes, and sometimes as a result of equipment or operator failure. To overcome such faults and to isolate faulty equipment we go for power system protecting relaying. The function of a power system relaying is to cause the prompt removal from service, of any element of power system, when it is subjected to short circuit or it starts to operate in any abnormal manner that might cause damage. There are enormous changes in relay technology through the world. The electromechanical relay in all of its different forms has been replaced successively by static, digital and numerical relays, each change bringing with it reductions and size and improvements in functionality. At the same time, reliability levels have been maintained or even improved and availability significantly increased due to techniques not available with older relay types. This thesis represents development of protective relays in Khartoum 110 KV substations. Different types of protective relays were collected from Khartoum 110 KV transmission and distribution substations as a sample of National Electricity Corporation (NEC) network substations. After this, statistics in 2011 were shown for different types of protective relays in all of these substations components (Distribution Feeders – High Voltage Transmission Lines – Power Transformers – Power Generators – Substations Busbars) and compare between different types of available protective relays types.