Low voltage ride through capability enhancement of wind farms´ generators: DVR versus STATCOM

This paper investigates the application of dynamic voltage restorer (DVR) versus static compensator (STATCOM) to enhance low voltage ride through (LVRT) capability of wind farms. The research done in the area of LVRT focused on a single machine compensation analysis; however, no such analysis was done for entire wind farms generators. Therefore, the main contribution of this paper is to study LVRT compensation through STATCOM and/or DVR in order to provide guidelines for the implementation of each solution within large wind farms. In this paper, squirrel cage induction generators (SCIGs) are studied using a simplified approach based on torque-speed characteristics of induction machines. The transient stability margin is proposed as indicator of LVRT capability. Analytical calculations are verified against simulation results using PSCAD/EMTDC package.