Improved VSM control of PMSG-based wind farms for transient stability enhancement

Abstract

This paper analyzes the optimal control strategy of PMSG-based wind farms during faults in order to improvethe transient stability of a power system with a high penetration rate of wind power. The investigated control strategiesare the unity power factor (UPF), reactive power control (RPC), and particularly the concept of virtual synchronousmachine (VSM). The transient stability level is assessed using the critical clearing time index, which was calculatedbased on trajectory sensitivity analysis. In light of the obtained results, it was found that RPC gives the best transientstability level, followed by the classical VSM control. Hence, an improved VSM control was proposed based on thetransient model of a synchronous generator. The improved VSM has shown a behavior similar to a real synchronousgenerator, which results in better transient stability performances.