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Mechanism of Large Scale Cascading Trip-Off of Wind Turbine Generators

This paper analyses the mechanism of large scale cascading trip-off failures of wind turbine generators in China, focuses on the reasons of trip-off caused by overvoltage. It analyses the model of Doubly Fed Induction Generation (DFIG) and builds a model of a wind farm that is composed of Doubly Fed Induction generators in DIgSILENT. The wind farm A with capacity of 175MW and wind farm B with capacity of 175MW is accessed to the nine bus system. The simulation reproduces the processes of the cascading trip-off of wind turbine generators caused by undervoltage and overvoltage. The trip-off caused by undervoltage is due to the lack of Low Voltage Ride Through (LVRT). And that the capacitive reactive power compensation device is not timely removed leads to a large surplus of reactive power, then the voltage rises, so the wind turbine generators trip off because of overvoltage. By setting the contrast scenario, the result shows that if capacitive reactive power compensation device is promptly removed after the loss of a large amount of active power, the wind turbine generators will not trip off because of overvoltage.