S. Mishra,∗ G.A. Taylor,∗∗ J.B.V. Reddy,∗∗∗ and M.H. Naeem∗∗∗∗


Differential Genetic Algorithm (DGA), Conventional Genetic Algo- rithm (CGA), reactive power injection, transmission loss minimiza- tion, VAR rescheduling List of Symbols n number of buses nl number of load buses ng number of generator buses nq number of capacitive reactive power injection nodes nt number of tap changing transformers Qi capacitive reactive power injection Qi,min and Qi,max capacitive reactive power injection limits Ti tap position of the transformer Ti,max and Ti,mi


This paper presents a method to reduce the transmission losses by using a Differential Genetic Algorithm (DGA) for VAR rescheduling. Considering all the standard equality and inequality constraints, solutions are obtained that minimize losses by changing the tap settings of various transformers and by varying the injected reactive power. It has been demonstrated that there are certain buses in the system where reactive power injections from capacitor banks can improve the voltage profile and reduce the transmission losses. In this paper minimum reactive power output of generators are kept at zero to care that generators do not draw reactive power. A comparison has been made to show that the DGA produces better results than the Conventional Genetic Algorithm with regard to loss minimization. This paper considers the New England 39-bus power system as a test case.

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