Comparison of multi-megawatt LVRT testing setups for the certification of wind turbines

This paper describes a comparison between two test setups for certifying wind turbines for connection to the electrical grid. The aim is to assess an alternative route to certifying wind turbines that eliminates environmental unpredictability and thereby expedites the certification process and improves repeatability. The paper focuses on fault-ride-through (FRT) testing. A multi-megawatt system level test bench is used to drive the turbine. In the first case, a test container is connected between the turbine and the public grid to simulate faults. This setup is representative of the current standard in-field test setup. In the second case, the grid is simulated using a converter based grid emulator that is proposed for the new test-bench based certification process. The comparison of symmetric no-load tests between the grid emulator and the reference implementation of the FRT container shows a satisfactory match of the voltage dip level, fault duration and the settling time.