Research On Micro-siting And Collection System Optimization Of Offshore Windfarm

Offshore wind resources are abundant in our country,and near load centers.With the upgrading of equipment manufacturing and construction technology,offshore wind farms are facing a new development opportunity.Location in the right place is the basis of a successful offshore wind farm,micro-siting determines where each turbine locates in the given area of a wind farm in order to reduce the wake effect and improve the production.In addtion,the number of wind turbines in large offshore wind farms is so large that the topology is relatively complex.Optimizing the topology of collection system can improve the economic and reliability of current collection systems.In traditional planning process of offshore wind farms,micro-siting and collection system is optimized after determining the locations of the wind turbines,which ignores their restrictive relation.This paper explains Jensen wake model and the improved wake model from the aerodynamic theory,analyzes the calculation procedures of the wake losses under the single and multi-direction wind situations,and the calculation process of the wake reduction coefficient of the wind farm are proposed.The wake loss is reduced based on the classical calculation.And then collection system optimization which is based on the knowledge of graph theory uses an improved Prim algorithm to get more pratical results.The algorithm can meet the limit of the transformer station incoming lines' number and its weights change dynamicly.The exmple proves that the improved algorithm can give more reasonable results.Furthermore,the relationship between micro-siting and the topology of collection system optimization is analyzed.A multi-objective planning model is built,which take the wake effect,economic and reliability of the collection system into account,and it is solved by an improved Pareto multi-objective optimization algorithm,and the final decision can meet different requirements.Finally,take an offshore wind farm's wind resource distribution for instance,this paper optimizes the the locations of the wind turbines and the connections between them,gives optimal solutions of uniform distribution,and selects the best solution which meets the requirements using analytic hierarchy process(AHP)method.