This paper presents an improved Genetic Algorithm (IGA) approach to solve the Reactive Power Dispatch (RPD) in power system incorporating thyristor controlled series capacitor (TCSC) devices. In this paper, the optimal location of the TCSC devices is found by sensitivity analysis for a given test system. 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 modifications 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 test and validation of proposed algorithm are conducted on two test systems: one is the IEEE 30-bus system, and the other is a reduced practical 76-bus Indian power system and is found to be more effective than the conventional methods.