Serial connection fault arc detection circuit

Abstract

The invention discloses a serial connection fault arc detection circuit. The serial connection fault arc detection circuit comprises a current sampling circuit (1), a noise suppression and amplification circuit (2), a rectifying circuit (3), a comparison circuit (4) and a control circuit (5), wherein the current sampling circuit (1) is arranged on a live wire of a detected line, and is used for outputting a current detection signal representing the current high frequency component of the live wire; the noise suppression and amplification circuit (2) is used for denoising and amplifying the current detection signal to obtain an alternating current high frequency signal; the rectifying circuit (3) is used for converting the alternating current high frequency signal into a direct current high frequency signal; the comparison circuit (4) is used for comparing the amplitude of the direct current high frequency signal with a preset voltage threshold so as to output a fault arc alert signal; and the control circuit (5) is used for outputting a protection signal according to the fault arc alert signal. The serial connection fault arc detection circuit can improve the accuracy for serial connection fault arc detection, and can reduce the mis-operation and refusal to operation situation for a protection device so as to improve the reliability of a fault arc protection device and realize stable working remotely or in the environment with serious electromagnetic interference.

Description

technical field [0001] The invention relates to electric power detection technology, in particular to a series fault arc detection circuit. Background technique [0002] Arc refers to the luminous discharge phenomenon produced by electricity passing through an insulating medium. The arc is characterized by high temperature, small current and short duration, and it will appear frequently once a breakdown point occurs. During arc discharge, a large amount of heat will be generated, which can ignite the surrounding flammable and explosive materials, causing fire or even explosion. Since alternating current is widely used in various electrical equipment, AC arc poses a great threat to electrical safety. [0003] In electrical appliances, it is necessary to use fault arc detection to prevent power failures such as poor contact of electrical power lines, aging lines and ignition, and to avoid electrical fires caused by line ignition. [0004] Series arc faults are arcing faults...

AI Technical Summary

Problems solved by technology

The amplitude of the high-frequency component generated by the series fault arc is low, and it is easy to be disturbed in the environment with a long distance from the power supply line or severe electromagnetic interference (such as a high-frequency switching power supply in the circuit)

The detection circuit without noise suppression is easy to misjudge the interference noise as a fault arc signal in such cases, resulting in malfunction

[0005] In order to avoid false actions caused by interference signals, the current circuit usually sets the detection threshold very high, which leads to the fact that when the load current is small (such as: the load is in a standby state), the series fault arc cannot be detected or can only be detected. It can only be detected when the arc is drawn violently

Unable to accurately judge small current load series arc fault

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