Multi-area hydrothermal coordination using modified mixed integer hybrid differential evolution

Abstract

This paper presents a novel modified mixed integer hybrid differential evolution (MMIHDE) algorithm, for solving the hydrothermal unit commitment of a multi-area power system. Differential evolution is a global optimisation technique that is exceptionally simple, significantly faster and robust. Hybrid differential evolution (HDE) overcomes the usage of large population, which results in lesser computation time. In case of a power pool that involves several generation areas interconnected by tie lines, the objective is to achieve the most economical generation policy that could supply the local demand without violating tie line capacity constraints. The inclusion of tie line security constraints makes the optimisation highly non-linear. Discrete and dynamic constraints such as unit start-up/shutdown and minimum-up/minimum-down time limits are also included in the multi-area hydrothermal unit commitment. In this paper, modifications are incorporated in the MIHDE algorithm as the basic DE algorithm exhibits difficulties in handling the equality constraints. The performance of the proposed approach is validated by illustration with standard test systems. The results of the proposed approach are compared with those techniques reported in literature. From the numerical results it is found that the MMIHDE based approach is able to provide better solution at a relatively lesser computational effort.