A Fault Location Method for AC Distribution Lines

Abstract

The invention discloses a fault location method for an AC distribution line, which comprises the steps of firstly setting a virtual negative sequence current vector by combining injection characteristics of negative sequence current when an AC distribution network breaks down; forming a node impedance matrix off-line according to the topological structure and parameters of the AC distribution network, and selecting rows where sparse measuring nodes are located to form a sensing matrix; measuring node voltage after the AC distribution network breaks down, calculating negative sequence voltage of the measuring nodes, and forming an underdetermined equation set together with the sensing matrix; and setting the nodes with the highest occurrence frequency of the largest element and the second largest element in the calculated virtual negative sequence current vector to be nodes at two ends of a fault area within the data window length so as to realize the location of the fault area. The method can greatly reduce the number of measuring points required by fault area location, is short in data used for fault location and can withstand transition resistance, certain noise and line parameter errors.

Description

technical field [0001] The invention relates to the technical field of fault diagnosis of an AC power distribution network, in particular to a fault location method for an AC power distribution line. Background technique [0002] The topology of the distribution network is complex and there are many lines. It has always been a difficult problem to locate the fault location accurately after a fault. At present, in the actual distribution network, the feeder terminal unit (feeder terminal unit, FTU) in the distribution automation function is mostly used to measure the fault current, and Isolate the faulty area. The FTU uploads the fault information and switch status information such as the magnitude and direction of the fault current, fault voltage and fault time to the master station, and the master station processes the information through the corresponding fault location method to locate the fault area, effectively improving the speed and accuracy of fault location . [0...

AI Technical Summary

Problems solved by technology

The fault area obtained by these two methods can only be determined between FTUs, but currently FTUs cannot be installed on every line. Therefore, even if the fault area is isolated, a large amount of manpower and material resources are still required for line inspection. If the fault area can be further reduced The fault range can be further shortened and the troubleshooting time can be further improved to improve the reliability of power supply.

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