An Optimized Strategy of Switching Crowbar Improve LVRT of DFIG Based on RTDS

The mathematical models of 2MW doubly-fed induction generator (DFIG) wind power generation system under steady and transient state are built in this paper. On the basis theory of control strategy and crowbar circuit parameter optimization, a complete model of DFIG low voltage ride through (LVRT) system is developed by real time digital simulator (RTDS). There is improvement in traditional crowbar protection method during quantitative simulation of grid voltage sag. An improved LVRT strategy of DFIG wind turbine by changing time of switching crowbar circuit is proposed in this paper. Contrastive study between traditional and improved LVRT method is provided to verify the performance of doubly-fed wind power system. Results show that the proposed method can realize uninterrupted operation of DFIG and meet the requirements of LVRT under grid voltage sag.