Voltage stability constrained reactive power planning using improved genetic algorithm

In this paper an Improved Genetic Algorithm (IGA) approach for solving the Reactive Power Planning (RPP) problem is presented. Generator bus voltage magnitudes, transformer tap settings and reactive power generation of the capacitor bank are taken as the control variables. While solving the RPP problem using genetic algorithm, the voltage magnitudes are taken as continuous variables, whereas the transformer tap setting and the reactive power generation of capacitor are taken as discrete variables. A binary-coded GA with tournament selection, two point crossover and bit-wise mutation is used to solve this mixed-integer non-linear optimization problem. Some modifi cations have been made in the representation of the solution variables in the genetic population in order to take care of the discrete nature of transformer tap setting and capacitor bank. The proposed algorithm has been applied to fi nd the optimal reactive power control variables in IEEE 30-bus system and in a practical Indian power system and is found to be more effective than the conventional methods and the simple Genetic Algorithm.