Method and device for low-voltage arc fault detection

Abstract

The invention relates to a method and a device for low-voltage arc fault detection. The device for low-voltage arc fault detection comprises a current transformer, an I / V converting circuit, an operational amplifying and rectifying circuit, a pulse shaping circuit and a micro controller which are sequentially connected. According to the invention, the current transformer detects load current signals, the I / V converting circuit converts the current signals into corresponding voltage signals, the voltage signals are inputted into the operational amplifying and rectifying circuit so as to be amplified and rectified to acquire absolute value signals with an appropriate proportion, the absolute value signals are shaped by the pulse shaping circuit so as to form rectangular pulse signals, the micro controller captures the pulse width time of pulse signals outputted by the pulse shaping circuit and judges whether the current waves at present are arc fault half waves or not through judging whether the pulse width time variation rate corresponding to current half waves of an adjacent period exceeds a threshold value under a corresponding current level or whether high-frequency impulses are captured continuously, thereby being capable of accurately detecting general load arc faults, cutting off the circuit in time, and ensuring the safety in electricity utilization.

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 of 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 ov...

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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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