Research Of Multi-objective Economic Operation For A Microgrid Considering The Randomness

Microgrid is a small power distribution system consisting of distributed power sources,loads,energy storage devices,energy conversion devices,monitoring and pro tection devices,it is an autonomous system with the ability to achieve self-control,ma nagement and protection,regarded as one of the key technologies of the smart grid.De velopment of microgrid can improve the utilization of renewable energy and the reliability of power supply.However,due to the diversity of microgrid operation state and the uncertainty of the output of the distributed generation,it is difficult to carry out optimal energy management.In order to get a reasonable solution to this problem,the mathematical models of commonly used components and combined heat and power in microgrid are presented in this paper,based on the research project "Key Technologies and Demonstration of the Effective and Reliable Microgrid Commucity Operation",the influences from such uncertain factors as the randomness of the forecast error during the operation of Microgrid are taken into further consideration,and the economic operation model with random variables in Microgrid is established.In terms of solving the model,different methods are applied according to the specific characteristics of the problem.The main work of this paper are as follows:The deterministic model of economic operation is established in this paper,with two operation targets including operation cost and environment cost,under two operation modes(grid-connected or stand-alone).Meanwhile,a method to solve the multi-objective planning problem and the optimization algorithm during the operation of microgrid is presented.According to the characteristics of the deterministic model of economic operation,the Pareto Optimal solution of the model is calculated in this paper,and is verified through examples subsequently.In order to deal with the randomness in the operation of microgrid,a method applying the chance constrained programming to the economic operation modeling of microgrid is presented in this paper.Because of the uncertain of the output of the wind generation,PV system and load forecast,the parameters of the forecast error is analyzed and the distributed functions are presented.The economic operation model of microgrid considering the randomness of forecast error is established.A deterministic method solving the chance constrained problem in the model is given.The effects of different confidence levels,different environmental penalty factors and different forecast errors on the economic operation of microgrid are analyzed in the example.The operation characteristics of the Combined Heat and Power are further analyzed,and the mathematical model of it is given in this paper.On the basis of the above,a stochastic optimal operation model containing Combined Heat and Power is established,aiming at solving the chance constraint problem in the model,a hybrid intelligent algorithm combining the stochastic simulation technique,neural networks and particle swarm optimization is proposed to solve the model,and the features of microgrid economic operation in both winter and summer are analyzed in the example.