Distribution automation system ground fault location method based on traveling wave measure and transient zero-module reactive power directions

The invention relates to a distribution automation system ground fault location method based on a traveling wave measure and transient zero-module reactive power directions. The method comprises the steps that firstly which feeder a ground fault is located on is determined by means of the small current line selection method of the traveling wave measure; secondly, based on the transient zero-module reactive power flow directions, a ground fault point is localized on a fault feeder, wherein on the feeder where the ground fault is located, the transient zero-module reactive power flow directions of any two adjacent feeder terminal units (FTUs) are monitored, if the product of the transient zero-module reactive power flow directions of some two adjacent feeder terminal units (FTUs) is negative, it is explained that the ground fault is located between the two adjacent feeder terminal units (FTUs), and if the product of the transient zero-module reactive power flow directions of some two adjacent feeder terminal units (FTUs) is positive, it is explained that no ground fault exists between the two adjacent feeder terminal units (FTUs). By means of the method, the ground fault is accurately localized, and which two feeder terminal units (FTUs) the ground fault is located between is determined, and good sensitivity is achieved to a high-resistance ground fault.