Research On Economic Dispatch Method For Islanding Microgrids Based On Distributed Control

The development of microgrids technology including distributed renewable energy is one of the key technologies for the development of smart grids in the future.However,due to the intermittent and fluctuating nature of renewable energy power generation,the problem of microgrids energy management,especially in islanding mode,is even more pronounced.At present,the energy management system of the microgrids mainly adopts a centralized control method,resulting in drawbacks such as large system traffic,high communication costs,easy blocking,and vulnerability to attacks.In the current research of microgrids energy management,distributed algorithms have received extensive attention due to their simple calculation,low requirement for communication network(only need local information)and fast computation convergence speed.In order to effectively solve the problem of optimal operation,the following research has been conducted on microgrids in islanding mode:(1)First,on the basis of extensive reading of literature,the current status of microgrids development is sorted out,and the research background,significance,and research status at home and abroad are summarized.The shortcomings of existing centralized control algorithms,such as large amount of communication information and high communication cost,are summarized.The advantages and disadvantages of distributed and centralized algorithms are compared,and the application prospects of distributed algorithms in microgrids are analyzed.(2)According to the characteristics of microgrids islanding operation mode,the optimal scheduling model is established with the minimum cost of system power generation as the goal.The slight increase in energy storage devices,loads,and distributed power is the optimal variable.Among them,the active power output of renewable energy sources is reduced when necessary;on this basis,a model is established that contains constraints on the upper and lower limits of the power of each micro source,and SOC upper and lower bound constraints of energy storage devices.(3)Based on the above established model,a distributed islanding microgrids economic optimal scheduling method based on Gossip algorithm is proposed.Through this method,the corresponding data exchange between neighboring nodes of microgrids,such as the micro incremental rate and power of the micro sources at each node,after several times of information exchange,each node micro source can get the system's global information.Therefore,the islanding microgrids system can quickly adjust the output power of the micro sources of each node without the need of a central controller,and maintain the system in a stable and economical state at the same time.(4)This paper takes a six node microgrids system with photovoltaic,wind turbine and energy storage as an example to perform step load,time-varying load and micro source faults on microgrids under ideal and non-ideal communication environments respectively.Simulations of different situations show that the proposed method can effectively make the islanding microgrids operate in an economically optimal state.For non-ideal communication environment,this paper presents a method to suppress communication interference.The simulation results verify its effectiveness and play an important role in practical applications.