Research On Day-Ahead Dispatch Of Wind Farm Integrated System Considering Safety Constraints

With the aggravation of environmental problems and the depletion of fossil energy, wind power is given more and more attention because it is both environmentally friendly and renewable. However, due to its randomicity and uncontrollability, it presents a significant challenge to power system security operation. Most important is it has disadvantageous effect on system load flow. So more meticulous of research is necessary in the system level control methodology of wind farm integrated system. The original dispatch method needs optimization and adjustment.Actually, static security constraints usually limit the generating capacity of normal units, which means it must be considered in the wind farm integrated problems. This paper is focus on the active day-ahead dispatch of wind farm integrated systems, especially the dispatch strategy considering safety constraints. What’s more, carbon emission reduction goal is introduced. It can exert an influenced on the dispatch cost. Details are as follows:(1) The uncertainty of wind forecast error and the influence of wind integration on system dispatch are studied. A normal distribution is used to describe the density function of wind power forecast errors. Also, reserve capacity is employed to stabilize the power fluctuation, which is expressed as a chance constraint.In this way, a day-ahead dispatch model of wind farm integrated system considering wind forecast error is presented. This optimization model is solved by genetic algorithm. The efficiency of the dispatch strategy is verified by the IEEE30system.(2) A day-ahead dispatch strategy of wind farm integrated system considering net safety is proposed. The uncertainty of wind power not only influences the system reserve, but also brings out the fluctuation of load flow. So a probabilistic load flow method of fast static security analysis is used, basing on the cumulant and Cram-Charlier expansion method. The technology of contingency sequencing is adopted to reduce the calculation quantity. In this way, static security constraint is considered in the day-ahead dispatch model of wind farm integrated system considering net safety, which solved by genetic algorithm. Though IEEE30 system, it proved that not only the economy of dispatch method, but also t security of system operation is guaranteed.(3) Based on the reduction of carbon emission, a day-ahead dispatch strategy of wind farm integrated system considering multi-objection is proposed. Through studying the solution of multi-objective optimization problem, a multi-objection dispatch model is presented, based on TOPSIS. Improved crowding niche genetic algorithm is used to avoiding premature convergence, as grey relative grade is applied to evaluate the relation of individuals. Based on the day-ahead dispatch model considering net safety, the multi-objection dispatch model for the cost and carbon emission is proposed. Via IEEE30 system, both the good convergence and validity are verified.