Solving dynamic economic emission dispatch problem with valve-point effects using hybrid DE-SQP

Dynamic economic emission dispatch (DEED) problem is used to determine the optimal generation schedule of on-line generating units by minimizing both fuel cost and emission simultaneously under load demand constraint, ramp rate constraint and other constraints. DEED with the consideration of valve-point effects is a complicated non-linear constrained multi-objective optimization problem with non-smooth and non-convex characteristics. The first purpose of this paper is to solve the DEED problem using a hybrid method which combines differential evolution (DE) and sequential quadratic programming (SQP). DE is used as a global optimizer and SQP is used as a fine tuning to determine the optimal solution at the final. A five-unit system with non-smooth fuel cost function has been taken to illustrate the effectiveness of the proposed method compared with other methods. The second purpose of this paper is to modify the DEED problem such that its optimal solution can be periodically implemented.