Detection method and device of direct current arc faults

Abstract

The invention discloses a detection method of direct current arc faults. The method is characterized by acquiring and computing a plurality of arc phenomena detection periods, confirming the arc phenomena, namely spark discharge phenomenon and arc discharge phenomenon by two feature extraction methods including a time domain standard deviation method and a Mahalanobis distance method based on time and frequency domains and counting the two phenomena respectively, and in the primary arc fault diagnosis period, judging that the arc faults exist if the total count of the two phenomena exceeds the given threshold and needing to judge whether suspected arcs appear if the total count of the two phenomena still fails to exceed the given threshold beyond the time. By the detection method, the arc faults in an electrified loop can be detected and protected. In a detection device, the current flowing through a sampling resistor is sampled, and when occurrence of the arc faults is judged, the trip signal is sent to a drive circuit of a power switch. The invention also discloses the detection device of the direct current arc faults, which can implement the detection method.

Description

technical field [0001] The invention relates to a detection technology, in particular to an arc fault detection device and method, which can detect and protect the arc fault occurring in the circuit. Background technique [0002] Arcing is a discharge breakdown phenomenon that changes an insulating substance (such as air) from an insulating state to a conductive state, allowing current to pass through. Under normal conditions, the gas has good electrical insulation properties, and when a large enough electric field is applied to both ends of the gas gap, it can cause current to pass through. This phenomenon is gas discharge, and arc is a kind of gas discharge. It has been verified by experiments that when the circuit is broken in the atmosphere, as long as the voltage exceeds 12-20V and the broken current exceeds 0.25-1A, a mass of extremely high temperature, strong light and conductive electricity will be generated in the contact gap. Approximate cylindrical gas conduction...

AI Technical Summary

Problems solved by technology

However, due to the complexity of the wavelet algorithm itself, without affecting the real-time performance of the algorithm, the hardware requirements are relatively high, which increases the production cost and is not conducive to wide application.

[0012] At the same time, due to the use of AC power in civil electrical systems, domestic research on arcs is mainly concentrated on AC arcs, while research on DC arcs is less involved

However, as mentioned earlier, DC power supplies are commonly used in aircraft electrical systems, and as the voltage level increases, the possibility of arcing increases greatly

Because there is no zero-crossing point in the DC arc, it is not easy to extinguish the arc. If it is not protected in time, it may burn for a long time, which often brings greater disasters.

Moreover, as a kind of arc fault, DC arc fault is very different from AC arc in the performance of current characteristics, and the method suitable for AC arc detection may not be effective in DC arc detection

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