STUDY OF POWER-FREQUENCY DYNAMICS AND DESIGNA NE2W HIGH PERFORMANCE UFLSSCH FOR EEPCOICS

Abstract

Power systems in many countries arc stressed towards their stability limit. In Ethiopia, the number of costumers and specific consumption of electricity is rapidly increasing. Ethiopian Electric Power Corporation (EEPCO) Interconnected System (ICS) is working very close to its limit. If these stable systems experience any unexpected serious contingencies, or disturbances, there is a significant risk of instability, which may lead to wide-spread blackout. Outage of generating units is one of such disturbances. frequency is a reliable indicator for such instability conditions that exist on the power system; therefore under-frequency load shedding technique is used to make the power system stable by shedding some load in case of generation deficit. ln this thesis, first, the power- frequency dynamics of EEPCO TCS is studied. Then. two conventional Under Frequency Load Shedding (UFLS) schemes arc designed analytically and one adaptive scheme is designed using dynamic simulation. Finally, the proposed load shedding schemes are tested on the detailed model of EEPCO transmission grid using Power System Simulation for Engineers (PSS/E) simulation software. The test result showed that all the proposed schemes improve the existing scheme but the adaptive scheme has better performance.