Incomplete information-based decentralized cooperative control strategy for distributed energy resources of VSI-based microgrids

Abstract

This paper presents an effective method to control distributed energy resources (DERs) installed in a microgrid (MG) to guarantee its stability after islanding occurrence. Considering voltage and frequency variations after islanding occurrence and based on stability criteria, MG pre-islanding conditions are divided into secure and insecure classes. It is shown that insecure MG can become secure, if appropriate preventive control is applied on the DERs in different operating conditions of the MG. To select the most important variables of MG, which can estimate proper values of output power set points of DERs, a feature selection procedure known as symmetrical uncertainty is used in this paper. Among all the MG variables, critical ones are selected to calculate the appropriate output power of different DERs for different conditions of the MG. The values of selected features are transmitted by the communication system to the control unit installed on each DER to control its output power set point. In order to decrease the communication system cost, previous researchers have used local variables to control the set point of different DERs. This approach decreases the accuracy of the controller because the controller uses incomplete information. In this paper, multi-objective approach is used in order to decrease the cost of the communication system, while keeping the accuracy of the preventive control strategy in an allowable margin. The results demonstrate the effectiveness of the proposed method in comparison with other methods.