Hierarchical Optimization for the Double-Sided Ring Structure of the Collector System Planning of Large Offshore Wind Farms

High reliability double-sided ring collector systems have been applied in practice for long distance and off the coast large-capacity offshore wind farms. To reduce investment and improve reliability, it is important to optimize and evaluate the double-sided ring collector systems. In this paper, a capital cost optimization model is developed to solve the mutual coupling effects among the system structure, power flow, and short circuit current in the collector system constraints. Based on the characteristics of the offshore electrical collector systems, the optimization model is divided into the offshore substation layer, the wind turbine layer, and the submarine cable layer. The fuzzy clustering algorithm, single parent genetic algorithm, and multiple traveling salesman solution technique are integrated and applied to solve the hierarchical optimization model. Finally, the proposed model and the optimization algorithms are tested in a real, large-scale offshore wind farm. The simulation results are compared with the radial collector systems from an economics and reliability point of view. The simulation results show that the double-sided ring design will achieve more profit with higher reliability in the long run. The results can also provide a benchmark for the collector system design of large-scale offshore wind farms.