Series arc detection method for low-voltage power distribution network

Abstract

The invention discloses a series arc detection method for a low-voltage power distribution network, and belongs to the field of electrical engineering measurement. The method is characterized by comprising the following steps: step a, setting monitoring nodes in a to-be-monitored line; step b, synchronously viewing the to-be-detected line and acquiring the voltage at the two ends; step c, performing filtering processing on the Uo; step d, obtaining a Us-Uo waveform; step e, executing the next step if the series arc fault occurs, and returning to the step b if the series arc fault does not occur; step f, counting the number of faults; and if a preset threshold value is exceeded, cutting off the circuit or sending an alarm signal; if not, returning to the step f. According to the series arc detection method for the low-voltage power distribution network, the series fault arc is detected by measuring the voltage difference between the head end and the tail end of the line, the method for judging the existence of the series fault arc by using the voltage information has the advantages that the influence of the load type and the load power is small, and the fault characteristics are more obvious, so that the judgment accuracy is higher.

Description

Technical field [0001] A series arc detection method for low voltage distribution networks belongs to the field of electrical engineering measurement. Background technique [0002] The series fault arc is a series discharge caused by poor contact with poor contact, loose terminal loose or poor contact. The series fault arcpoint is connected in series in the line, which has the characteristics of continuous occurrence. When the series arc continues to occur for a while, it may cause a fire. When the series arc occurs, its current waveform has occurred: the current waveform has a zero-break zone. The current increase rate is high, the current harmonic content is increased, the current valid value is small, the positive and negative half-week is no longer symmetrical, the load is different. Unlike the load power, the degree of expression of these fault features will also be different. The existing method of detecting the series fault arc is mainly implemented by detecting the above ...

AI Technical Summary

Problems solved by technology

[0003] The difficulties in series fault arc detection include: (1) The series fault arc is connected in series with the end load, and its fault current is equal to the load current, so it cannot be protected by the current threshold; (2) There are various loads in low-voltage distribution lines, The load current in normal operation of this type of equipment has the same or similar current waveform characteristics as that of linear loads when a series fault arc occurs, so it is difficult to find a fault characteristic detection standard suitable for various loads, resulting in the success of the current series fault arc detection low rate

(3) When a series fault arc occurs, its current fault characteristics will be affected by the load power

(4) Partial loads also have the current characteristics of series fault arcs when starting, so it is easy to cause misjudgment

(5) Partial loads such as arc welders, arcs generated when brushed motors are working, and arcs generated when plugging and unplugging sockets have fault characteristics similar to series fault arcs, which increases the difficulty of detecting series fault arcs

(6) For weak series arc faults with very short arc time or very small arc current, the fault characteristic quantity in the current waveform is often not obvious, which makes it difficult to detect weak series fault arcs, and lays hidden dangers for arc-induced fires

[0012] This method considers that when there is an arc, the difference between the voltage waveforms of the load terminals in two adjacent cycles is relatively large, so the average value of the voltage difference waveforms of adjacent cycles is larger than that of the adjacent cycles when there is no arc, because when the arc occurs The characteristic is random, so this method is prone to misjudgment, and this method is also prone to misjudgment when the load terminal voltage changes caused by the load type and load power change when the line is normal

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