Based on the current limit DC transmission method commutation failure prevention method

The present invention provides a current limiting based HVDC converter failure defense phase method, the method comprising the steps of: I, commutation failure type bus fault detection based on the output signal of the detection current transmission system; II, the use of current limit method to reduce the DC current command value and continuously 60-100ms; III, determining whether the malfunction is eliminated and the DC power transmission system whether to restore the off angle; IV, determination result of the determination in accordance with the DC current command, until the fault is cleared, restore the DC current command . This method avoids early triggering DC current increase caused, adversely affect the power factor angle is increased direct current transmission system and the like, failure of the AC system to make timely and effective reaction, the desired area of ​​the commutation thyristor is reduced, defense in favor of HVDC transmission system fault occurs commutation failure.