OPTIMAL LOAD SHEDDING FOR MINIMUM UNDER FREQUENCY USING EXPERT SYSTEMS

Document Type : Original Article

Author

Associate Professor of Electrical Power Engineering, Faculty of Engineering (Shoubra) , Zagazig University.

Abstract

The under-frequency problem due to disturbances in large interconnected power systems, may lead - if not corrected -to an extensive serious damage. Disturbances in large power systems sometimes cause this interconnected systems to become separated into isolated subsystems, and this may lead to excess load, however, overloads the generating units causing the frequency to drop to levels that may cause permanent damage to steam turbines. Load shedding are often applied throughout the system to avoid the turbine damage by restoring the frequency. It helps in restoring frequency in appropriate amount taking into consideration that there is no need in shedding excessive amounts of load. So minimum load shedding for under-frequency is needed which is the main aim of this paper with the help of an expert system.
This paper treats the under-frequency problem by using an adaptive traditional method for setting of the under-frequency relays. And an expert system is then suggested and developed as a perfect and fast method to accelerate the optimal shedding process for minimum frequency limit. These methods are implemented and applied on a simple power system. The obtained results are presented and discussed with a comparison between the traditional and suggested expert system methods.

Keywords