Parallel arc fault positioning method and system of low-voltage distribution network

Abstract

The invention provides a parallel arc fault positioning method and system of a low-voltage power distribution network. The method comprises the following steps that a monitoring node performs low-pass filtering on a voltage acquisition signal of each cycle; the magnitude of each phase voltage of the line is monitored by taking a cycle as a unit, and the monitoring of the line voltage is synchronously completed according to the phase voltages; when what is detected is that the magnitude change of a certain phase voltage exceeds a set threshold value alpha in a certain cycle, fault information is judged to be monitored, that is, the cycle is judged to be a fault cycle; the effective value data of the phase voltage of the fault cycle is sent to gateway equipment, the gateway equipment groups the received effective value data of the phase voltage of the fault cycle, and finds the most upstream monitoring node in the group with the minimum average value according to the line topology structure of the transformer area low-voltage network, and judges that the fault point is close to the upstream line of the most upstream monitoring node. The fault point can be positioned by using the difference of the distributed monitoring points influenced by the arc voltage of the fault point and the voltage of the power supply.

Description

technical field [0001] The invention relates to the field of electrical engineering measurement, in particular to a parallel arc fault location method and system for a low-voltage power distribution network. Background technique [0002] Low-voltage power distribution lines are subject to many factors such as physical friction and chemical erosion, which may cause aging, wear, and poor contact of the insulation layer of the line cables, which may cause arc faults. The arc temperature generated by a current of 0.5A can be as high as 2000-3000°C, which is enough to ignite any combustibles, and when the maintenance voltage of the arc is as low as 20V, the arc can still exist continuously and stably, and it is difficult to extinguish. Therefore, the fault arc is usually caused important cause of fire. [0003] Most of the existing research on arc detection is aimed at the detection of arc presence or absence, that is, by detecting whether a fault arc occurs and by cutting off t...

AI Technical Summary

Problems solved by technology

[0008] To sum up, the method of using the current mutation characteristics to realize parallel arc fault location has the problems of difficult setting of the threshold, misjudgment easily caused by load fluctuation, and high cost caused by the installation of equipment on all branch lines.

[0009] At present, there are patents that use the influence of the arc voltage at the fault point when the parallel arc occurs to its downstream line voltage to realize the parallel arc fault detection method, but this patent can only detect the existence of the parallel arc fault, and cannot solve the parallel arc fault Point positioning problem

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