Research On Security Control Of Microgrid Based On Risk Avoidance

Microgrids offer a viable solution for integrating distributed renewable energy into power systems on a large scale.They allow for flexible control of renewable energy output characteristics through power electronic devices,improving the utilization of new energy generation.However,due to the intermittent and fluctuating nature of renewable energy,as well as the low inertia characteristics of power electronic equipment,the operational status of microgrids is susceptible to changes,posing potential risks of frequency and voltage instability,which can threaten the stability and safety of microgrids.This article focuses on frequency security control of microgrids,considering possible changes in their operational status.It investigates the use of Markov jump modeling and Model Predictive Control(MPC)methods for microgrids and proposes a risk-averse MPC-based frequency security control method for microgrids,effectively achieving frequency security control.The specific research content is as follows:(1)To accurately describe the operational characteristics of microgrids,a Markov jump model of microgrids is established based on the theory of Markov jump systems.This includes detailed modeling methods based on distributed generation small-signal modeling,as well as simplified modeling methods based on the input and output characteristics of distributed generation.This study provides a model foundation for implementing frequency control.(2)For microgrid security control,this article studies risk measurement methods and risk avoidance MPC methods that can quantify risks.This includes multi-stage risk measurement,risk stability,and optimization of risk-averse MPC problems.This study provides a methodological basis for implementing frequency control.(3)A risk-averse MPC-based frequency security control method for microgrids is proposed.Firstly,a cost function reflecting frequency deviation is established based on the mathematical model of microgrids.This is combined with risk measurement indicators to form a multi-stage risk objective function that comprehensively measures future frequency changes.Then,based on the objective function and risk-averse MPC method,a frequency safety control scheme is designed for the microgrid.Finally,MATLAB/Simulink simulations are conducted to verify the effectiveness of the proposed control method in maintaining the frequency of the microgrid,and it is compared with the random MPC method.The experimental results show that the proposed control method can effectively reduce the impact of risk events on system frequency and enhance the frequency security of the microgrid.