Review of voltage sag generator for wind power

The VSG(Voltage Sag Generator) is used to test the LVRT(Low Voltage Ride-Through) capability of wind power system,and its research work at home and abroad is summarized in detail.Three solutions are discussed: impedance-type VSG simulates voltage sags by adding series or parallel impedance in main circuit;transformer-type VSG simulates voltage sags by changing transformer combinations or taps;electronics-type VSG simulates voltage sags by using semiconductor power devices,which is more functional.Their work principles and implementations are analyzed and compared.Transformer-type VSG is widely used now because of its simple structure,high reliability and low cost,while electronics-type VSG will get more applications for its small size and better performance.