Dynamic Economic Dispatch Considering Real Operation Characteristics Of Units

The valve point effect,prohibited operation zones and multiple fuel option are ignored in the traditional model of economic dispatch in order to keep the model with the characteristics of convex optimization.In this paper the valve point effect,prohibited operation zones and multiple fuel option are all considered to ensure the accuracy of the economic dispatch model,which will make the model more complicated.non-differentiable and non-convex.Mathematically speaking,the dynamic economic dispatch considering the valve-point effect,prohibited operation zones and multiple fuel option is a high-dimensional,non-convex and nonlinear optimization problem.The methods used to solve such problems are mainly divided into two major types which include mathematical optimization algorithms and heuristic algorithms.Firstly,we study the characteristics of the optimal solution of the static economic dispatch with valve point effect because the valve point effect will produce a large number of local minima in the solution space,which have a very large influence on our proposed mathematical programming algorithm.And the local minimum of the problem satisfies that most of the units are running on the valve point including the upper and lower output power limits of generators with a relaxed unit to adjust the power balance.Then,we study and program two methods for global optimal solution of the problem.The first method is Traverse search method(TSM)algorithm for the system with few units and the second one is Dimensional steepest decline method(DSD)algorithm for the large system.Secondly,we further study the dynamic economic dispatch with valve point effect and propose a mixed integer quadratic programming(MIQP)and mixed integer linear programming(MILP)combined with the warm start technique,range restrict scheme and the multi-step method to solve this non-convex and nonlinear problem.We also propose a two-step method by combining MILP with DSD algorithm to solve this problem quickly.By programming and testing in GAMS software,it can be proved that both of the methods can obtain the excellent economic dispatch solution quickly and steadily.Finally,we study the dynamic economic dispatch considering the valve point effect,prohibited operation zones and multiple fuel option and the model is most complex.The problem is solved by the mixed integer quadratic programming algorithm the warm start technique,range restrict scheme and the multi-step method.The feasibility and validity of the algorithm are verified by the results of the example.