Search For Optimal Ocean Tidal Current Turbines Positioning Strategy

A boom in development of ocean tidal current energy technology is accompanied with the utilization of green energy. But for any given background in a tidal farm, existing problems on layout scheme of tidal current turbines and the turbine wake influence the output energy. Several researches indicated that the wake among wind turbines reduce rate the energy capture in a wind farm, the layout scheme of wind turbines should considering the wake influence. Though tidal and wind are different from each other, they do have a few similarity, the wake formed by unreasonable layout scheme of tidal current turbines would seriously influence the ratio of cost and output. Thus. how many tidal current turbines can be placed in a given area and how to positioning the turbines to maximize the output energy become two urgent problems to be solved.This paper summarizes the study history of tidal energy utilization technology and layout scheme. and proposes a new optimal algorithm based on extensive analysis and research, to solve the problems in optimal layout of tidal current turbines and rational development in the given tidal area. First, build a three dimension modal by considering the geography and tidal speed influencing factors in the tidal farm, and the best intalled turbine number is obtained by minimizing the cost of unit output energy in the given tidal farm, then the optimal layout scheme of the turbines is achieved by tuning position of each turbines where get the maximal total output energy through a period of time; the optimization problem is then summarized as multi-constraint and multivariate nonlinear optimization problems. Second, the wake after a tidal current turbine is simulated by CFD technology, and choose the best wake modal by analyzing the error in the alternative wake modal compared with CFD wake data, and Jensen wake modal is selected for the ultimate calculation in the optimization problem. Third. after a comprehensive and deep discussion on the regular penalty function modal, proposed a improved adaptive penalty function based on particle swarm optimization algorithm for a new algorithm applying on the layout optimal problem; according to the ratio of feasible individuals in the whole individuals, the algorithm transforms the object function, builds a whole new adaptive penalty factor, and the penalty factor changing in the process of optimization to penalty the constraint violation in a appropriate degree, thus the algorithm could guide the individuals to the feasible area and optimal position. Last, sea conditions and actual tidal turbine parameters is used in the final simulation, result shows that the analysis and derivation of improved algorithm is correct, feasible schemes seeking effects and the turbine layout effects are better. Total output energy of the tidal farm is apparently enhanced in every tidal speed than empirical layout scheme and other layout schemes obtained by similar algorithms.