Knowledge-based expert system for optimal reactive power control in distribution system

In this paper a knowledge-based expert system for the general capacitor placement problem is formulated by taking into account the practical aspects of capacitors, load constraints and operational constraints at different load levels. The developed expert system uses the simulated annealing (SA) technique for global optimal solution for reactive power compensation. The SA technique is made suitable for an expert system by providing the initial estimate and placement of reactive sources using the set voltage magnitude method (SYM). A set of rules is developed which is capable of modifying the step size of the control variable when ever the toggling of the control direction is detected. General rules are developed for optimal reactive power control. The developed expert system is tested for a practical 85-bus radial distribution system of Mysore City, South India. The results obtained are encouraging and acceptable in practice.