Demand Response Participates In The Control Strategy Research Of Frequency Regulation Of Microgrid

The development and utilization of clean and renewable energy provides an ideal solution to the global energy crisis,but also brings severe challenges to the frequency stability of power system.Although micro grid provides an effective way to solve the problem of large-scale distributed generation grid connection and give full play to the efficiency of distributed generation,it also has serious deficiencies in frequency stability.The demand response provides a new idea for frequency regulation of micro grid.Based on that,this dissertation studies the control strategy of demand response participating in micro grid frequency regulation,which has very important practical significance.Based on the introduction of power system frequency regulation principle and micro grid,this dissertation studies the generation characteristics of various distributed generation,builds a micro grid load frequency control model including micro gas turbine,hydrogen storage system,wind power generation and power load,deeply analyzes the mechanism of demand response participating in micro grid frequency regulation.In addition,the necessity and feasibility of demand response participating in micro grid frequency regulation are clarified,and the related research is carried out around its control strategy:(1)The load frequency control strategy of micro grid with hydrogen storage system is studied,and the electrolytic water load in hydrogen storage device is proposed as demand side resource to participate in micro grid frequency regulation.Based on the model of hydrogen storage system including fuel cell and electrolyzed water load,the control scheme of hydrogen storage system participating in micro grid frequency regulation is formulated,and the fuzzy PI controller with demand response is designed.Finally,from two aspects of different demand response control strategies and load participation,the simulation of demand response participation in micro grid frequency regulation is carried out.The experimental results show that better demand response control strategy and richer demand response load participation play a positive role in improving the frequency regulation effect of micro grid.(2)In order to further study the influence of demand response control strategy and load participation on micro grid frequency regulation,it is proposed to use aggregate variable frequency air conditioning as demand side resource to participate in micro grid frequency regulation.On the basis of the previous research,the influence of wind power randomness on micro grid frequency regulation is further considered.Firstly,the thermodynamic model of the building,the electrothermal conversion model of the air conditioner and the demand response model of a single air conditioner are systematically introduced.Based on this,a scheme of load group aggregation control for variable-frequency air conditioner is proposed.Then,based on the establishment of the simulation wind power stochastic model,the load frequency control model of the aggregation variable frequency air conditioning participating in the micro grid frequency modulation is established,and the variable domain fuzzy PI controller is designed for the load of the variable frequency air conditioning.Finally,considering the randomness of wind power and load,the simulation results show that the strategy can improve the speed of frequency regulation and reduce the overshoot significantly,adapt to the requirements of timeliness and accuracy of micro grid frequency regulation,and help to improve the performance of micro grid frequency regulation.