Low-voltage arc fault detection method

Abstract

A low-voltage arc fault detection method comprises collecting current signals in a loop through a current sensor, obtaining fundamental frequency analog signals and high frequency analog signals, achieving accumulating calculation of the fundamental frequency analog signals and high frequency analog signals of power frequency cycle through an integrating circuit, an interrupt trigger and a timer, and further obtaining higher harmonic occupancy. According to the method, whether arc faults occur is judged by real-time monitoring of change characteristics of the line current higher harmonic occupancy and calculation of over-limit times of the higher harmonic occupancy, normal arc and fault arc which are generated by some special electric appliance loads and normal on-off action are distinguished by judging whether higher harmonic occupancy changes caused by the arc faults are periodic and judging occurring frequency, occurrence of the arc faults can be detected in real time, the method is not limited by an installing position, malfunction caused by disturbance of operating arc generated by normal circuit opening and closing and loads such as a switch power and a dust collector can be avoided well, and the reliability is high.

Description

technical field [0001] The invention relates to an arc fault detection method of a low-voltage power supply and distribution system, in particular to an arc fault detection method based on the variation characteristics of line current high harmonic wave occupancy. Background technique [0002] The breakage, short circuit and poor contact of the power supply circuit due to aging and damage can all lead to arc faults. Under normal load, an arc fault can generate a local high temperature above 2000°C in a very short period of time, which is enough to ignite the flammable and explosive materials around the wire and cause a fire, seriously endangering the safety of public life and property. Because when an arc fault occurs, the loop current is lower than the rated current of the overcurrent protector, except for the ground arc, the arc fault will not generate residual current, and the detectors used for overcurrent and residual current cannot prevent arc fires. . [0003] Exist...

AI Technical Summary

Problems solved by technology

[0004] Although the conventional arc fault protection devices described above can be used to detect and distinguish arc faults from load disturbances, there is still a need for arc fault detection techniques with higher reliability

Traditional arc fault detection devices often cannot reliably distinguish between periodic and non-periodic arcing events, resulting in nuisance tripping

And disturbing loads such as dimmers, vacuum cleaners, etc., when these equipment settings are changed, high voltage transients can be generated, resulting in rising or falling arc discharges in continuous time periods, and traditional arc fault detection devices are often difficult. Distinguishing between arc faults and arcing events

Therefore, the traditional arc fault detection method has many shortcomings and needs to be further improved.

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