With the rapid increase of wind farms,the grid code needs to be improved to meet the requirement of wind farms and enhance grid stability.Doubly-fed induction generators are largely used in wind turbines,but they are ...With the rapid increase of wind farms,the grid code needs to be improved to meet the requirement of wind farms and enhance grid stability.Doubly-fed induction generators are largely used in wind turbines,but they are very sensitive to grid disturbances.The voltage swell can be caused by switching on capacitor banks or switching off large loads,which may result in the reversal of the power flow in the grid convertor;the current may flow from the grid into the DC link,which may step up DC voltage,and result in large faults of rotor currents and instantaneous power oscillation.The grid reactive compensation devices can not have the automatic swithing function after the low voltage fault,which will result in local reactive power surplus,so some wind power generators will retreat from the grid under high voltage protection.展开更多
文摘With the rapid increase of wind farms,the grid code needs to be improved to meet the requirement of wind farms and enhance grid stability.Doubly-fed induction generators are largely used in wind turbines,but they are very sensitive to grid disturbances.The voltage swell can be caused by switching on capacitor banks or switching off large loads,which may result in the reversal of the power flow in the grid convertor;the current may flow from the grid into the DC link,which may step up DC voltage,and result in large faults of rotor currents and instantaneous power oscillation.The grid reactive compensation devices can not have the automatic swithing function after the low voltage fault,which will result in local reactive power surplus,so some wind power generators will retreat from the grid under high voltage protection.