An Improved Differential Evolution Method Based on the Dynamic Search Strategy to Solve Dynamic Economic Dispatch Problem with Valve-Point Effects

Guangyu Chen,Xiaoqun Ding

doi:10.1155/2014/175417

Abstract

An improved differential evolution (DE) method based on the dynamic search strategy (IDEBDSS) is proposed to solve dynamic economic dispatch problem with valve-point effects in this paper. The proposed method combines the DE algorithm with the dynamic search strategy, which improves the performance of the algorithm. DE is the main optimizer in the method proposed. While chaotic sequences are applied to obtain the dynamic parameter settings in DE, dynamic search strategy which consists of two steps, global search strategy and local search strategy, is used to improve algorithm efficiency. To accelerate convergence, a new infeasible solution handing method is adopted in the local search strategy; meanwhile, an orthogonal crossover (OX) operator is added to the global search strategy to enhance the optimization search ability. Finally, the feasibility and effectiveness of the proposed methods are demonstrated by three test systems, and the simulation results reveal that the IDEBDSS method can obtain better solutions with higher efficiency than the standard DE and other methods reported in the recent literature.

Highlights

The dynamic economic dispatch (DED) is very important optimization problems in the power system operation, which is a complicated nonlinear dynamic constrained problem [1], and its purpose is to find the optimal combination of power outputs of all generating units to minimize the total fuel cost and satisfy all equality and inequality constraints during all the dispatch periods
The details of the best dispatch result obtained by the proposed IDEBDSS method are provided in Table 3, which demonstrates whether the constraints of the problem are satisfied or not
An improved differential evolution method based on the dynamic search strategy is presented to solve DED problem with valve-point effects

Summary

Introduction

The dynamic economic dispatch (DED) is very important optimization problems in the power system operation, which is a complicated nonlinear dynamic constrained problem [1], and its purpose is to find the optimal combination of power outputs of all generating units to minimize the total fuel cost and satisfy all equality and inequality constraints during all the dispatch periods. The generating unit fuel cost function is represented approximately as a nonlinear convex quadratic function. In this approximation, the valuepoint effects of generator are not considered, so that the inaccuracy of the dispatch results is inevitable. In reality, convex fuel cost function cannot be exhibited by the generating units due to steam valves in large steam turbines, and the generator exhibits the characteristics of nonsmooth and nonconvex mathematically. From the perspective of math, the DED problem with valve-point effects can be categorized as a dynamic nonlinear optimization problem with nonsmooth and nonconvex characteristics subjected to various equality and inequality constraints. It is a challenge to find the optimal dispatch result in a reasonable computation time

Methods

Results

Conclusion