On-Site LVRT Testing Method for Full-Power Converter Wind Turbines

Low-voltage ride-through (LVRT) capability is now required for all large-scale wind turbines (WTs) connected to the grid. This paper presents an on-site LVRT testing method for full-power converter (FPC) WTs. The new method makes use of the already installed WTs to emulate the grid and produce a given fault for the WT under test. To guarantee the safety of grid, both the test and grid emulation WTs are disconnected from the network and operate in stand-alone mode during the test. The system configuration, testing procedure, and control strategies are studied in the paper. Practical issues including the capability of emulated grid, WT overspeed limitation, network impedance, and fault conditions emulation are discussed. A wind farm with typical 2-MW FPC permanent magnet synchronous generator (PMSG) WTs is modeled in MATLAB. Simulation results show that with only proper modifications of a WT control algorithm, it is feasible to conduct on-site a series of LVRT tests for the FPC WT safely under given conditions.