Low-voltage arc fault detection method and device

Abstract

The invention relates to a low-voltage arc fault detection method and device. The low-voltage arc fault detection device includes a sequentially connected current transformer, an I / V conversion circuit, an operational amplifier rectifier circuit, a pulse shaping circuit and a microcontroller. The invention detects the load current signal through the current transformer, converts the current signal into a corresponding voltage signal through the I / V conversion circuit, and the voltage signal is input into the operational amplifier rectifier circuit for amplification and rectification to obtain an absolute value signal of a suitable ratio, and the absolute value signal Then the pulse shaping circuit is shaped into a rectangular pulse signal, and the microcontroller captures the pulse width time of the pulse signal output by the pulse shaping circuit, and judges whether the pulse width time change ratio corresponding to the current half-wave of the adjacent cycle exceeds the threshold value under the corresponding current level Or whether high-frequency pulses are continuously captured to determine whether the current half-wave is an arc fault half-wave, which can accurately detect general load arc faults and disconnect the circuit in time to ensure power safety.

Description

technical field [0001] The invention relates to the field of arc fault detection in low-voltage power distribution systems, in particular to a low-voltage arc fault detection method and device that are not easily disturbed by normal operating current changes. Background technique [0002] According to relevant statistics, fires caused by electrical causes top the list among all kinds of fires, accounting for about 30%. A large proportion of electrical fires are caused by arc faults. These dangerous arcs can occur on poorly designed or aging power supply lines, appliance plugs, and power cords, internal wiring harnesses, or component insulation in household appliances. The characteristic of the fault arc is that the current in the line may decrease, but the temperature is high, and the fault expands rapidly until the nearby combustibles are ignited and a fire is caused. Therefore, it is particularly important to prevent such fires caused by arc faults. [0003] Traditional...

AI Technical Summary

Problems solved by technology

[0004] At present, although the installation of arc fault protection devices in my country has not been mandatory, and such products have not appeared on the market

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