Verification of DFIG and PMSG wind turbines' LVRT characteristics through field testing

Low voltage Ride through (LVRT) capability has become more and more an issue for newly integrated wind turbines. To the best of our knowledge, this paper is the first to develop field tests for real wind turbines on Northeast China wind farms. It is therefore different from other papers that validate LVRT control strategies through running software simulations on a computer. To examine a single wind turbine's LVRT capability, wind turbine's terminal voltage dip is achieved by using a grid voltage dip emulator, which is located on the 690V side of the generator transformer. Apart from that, short circuiting a wind farm's 35kv transmission line is implemented to testify a wind farm's LVRT capability. This short circuit test is more efficient than the previous one to deal with massive wind turbines in a large area. By artificially making various grid fault circumstances, dynamic behavior of DFIG and PMSG wind turbines are analyzed and compared in both of these tests. Various control strategies such as active/passive crowbar and chopper protection schemes are verified in reality. New active/reactive power compensation methods are investigated and compared.