Method for detecting direct-current short-circuit fault of MMC-HVDC based on transient energy

The invention discloses a transient energy-based MMC-HVDC direct-current short-circuit fault detection method, which comprises the steps of constructing vectors according to transient energy of bridgearm capacitance and direct-current inductance of an MMC-HVDC, and performing fault judgment according to the change of the transient energy vectors: when the change of the transient energy vectors exceeds a threshold value, starting detection; when the interval positioning criterion is greater than a set value, judging that the fault occurs in the region, otherwise, judging that the fault occursoutside the region; for the sending end station, when the fault line selection criterion of a certain line is larger than a set value, judging that the line breaks down, and otherwise no fault occurs;when the direct-current short-circuit fault identification criterion of the line is greater than a set value, judging that a direct-current short-circuit fault occurs, otherwise, judging that a powerfluctuation or lightning st