| With the development of global economy and the aggravation of energy consumption,renewable energy has gained more and more attention.In recent years,energy supply for the development and utilization of China’s coastal islands has become an urgent problem to be solved.The island region is rich in wind/solar resources,but the wind/solar power generation is intermittent and uncertain due to the great changes in the environment,which leads to the imbalance between supply and demand and the phenomenon of high abandoned new energy power.In order to solve this problem,this article points out the necessity of the wind-solar-diesel-storage mixing system in this area.Pumped energy storage and hydrogen energy storage have the characteristics of clean green,large capacity,long operating life,and easy storage.They are considered to be ideal long-term energy storage solutions.The flexible control strategy is developed based on the operating characteristics of equipment and the energy storage capacity is optimized.These measures can improve the reliability of electricity consumption and the utilization rate of renewable energy in the islands and reduce the total cost of the system.This paper studies the control strategy and optimal configuration of the hybrid micro-grid system in coastal islands.The main work contents are as follows:1.The mathematical models of wind turbines,photovoltaic,diesel,battery and energy storage equipment are set.This paper summarized and analyzed the conditions of wind/solar resources in the coastal areas of China,and made a map of wind/solar resources in the coastal areas.The advantages of wind-solar hybrid power system are affirmed by analyzing the seasonal complementary of wind-solar.At the same time,the applicability of wind-solar system to cold and heat demand in different climatic regions is classified.The results show that the cooling and heat demand load fluctuation is small and the wind-solar hybrid system is suitable.By analyzing the supply and demand imbalance between day and season in the island area,the necessity of establishing the hybrid energy storage system is determined.2.In this paper,two hybrid energy storage systems are proposed and the operating characteristics of each unit are considered based on heuristic rules.Then,using the fuzzy control principle,a four-stage flexible control is proposed.The simulation results show that after adopting the flexible control strategy,the fresh-water pool state is better,the battery average SOC is better,and the battery life is longer.The load state of each device is good,which reduces the running time of the device and significantly reduces the annual value cost by 3.95%.After increasing long-term storage,wind/solar abandoned rates fell from 29.37% to 20.25% and 16.49%,respectively.Diesel power generation and pollutant emissions have been reduced by more than 50%.When pumping energy storage and hydrogen energy storage reduced wind/solar abandoned rates and diesel engine use,the equivalent annual cost of differences due to system differences decreased by 12.26% and10.35%,respectively.However,in order to reduce the abandoned rate of wind/solar energy,the choice to increase the battery capacity,the curtailment rate change range is small,but the annual cost increase of 5.25% is not worth the loss.3.This paper introduces the capacity optimization method of wind/solar/diesel/storage hybrid power generation system in detail.In this paper,the objective function including system life cycle cost,renewable energy permeability and pollutant emission is proposed.Taking the flexible control proposed in this paper as the operation strategy,the intelligent optimization algorithm is used to configure the energy storage capacity of the system,and finally the optimal configuration of energy storage capacity in the system is obtained. |
PDF Full Text Request