An Evolution Strategy with stochastic ranking for solving reactive power optimization

This paper presents an algorithm for solving reactive power optimization problem through the application of Evolution Strategy (ES) with stochastic ranking. In order to better improve the optimization performance and practicality, the coding method for integer data of transformer tap position is designed deliberately and the self-adaptive optimization termination condition based on variance is also presented. Under simulated conditions, the proposed method has been tested on IEEE-14 and IEEE-118 bus systems. The optimal reactive power results obtained using improved ES are compared with initial power loss. It is shown that our strategy can decrease respectively nearly 4.43% and 4.3% of initial loss.