Method for detecting arc faults based on time-frequency characteristics of high-frequency current component

Abstract

The invention discloses a method for detecting arc faults based on the time-frequency characteristics of high-frequency current component. The method comprises the following steps: measuring the transient high-frequency current in a primary loop by using a self-integrating Rogowski coil and performing the spectrum analysis of the high-frequency current; measuring the time difference between the zero-crossing time of a power-frequency current and the time that the signal of the transient high-frequency current appears by adopting a counting method via using an interrupt trigger and a timer / counter, so as to confirm the phase angle position where the high-frequency current occurs in the protected loop load current; and judging whether an arc fault is caused or not according to the spectrum characteristics of the high-frequency current, the phase angle position where the high-frequency current signal occurs and regularity of the signal of the high-frequency current. The invention is capable of detecting arc faults in the normal power supply, is limited by installation position slightly, can distinguish the transient current generated by normally connecting / disconnecting a circuit from the power electronic-load current of the switch power supply and the like, and reduces and avoids misoperation.

Description

technical field [0001] The invention relates to a detection method for an arc fault in a low-voltage power supply and distribution line or a power supply and distribution system, in particular to a detection method for an arc fault based on the time-frequency characteristics of a high-frequency current component. Background technique [0002] Arc faults are often caused by insulation damage of some wires in a bundle of wires or disconnection of conductive loop joints, and their current may be less than the rated current of the line. In the low-voltage power supply and distribution lines and the power supply and consumption systems of buildings, household appliances, automobiles, and aircrafts, there is a threat of arc faults to a certain extent. The high concealment of arc faults and its strong destructive power can easily cause equipment damage, fire or even explosion, seriously endangering the safety of public life and property. Due to the large energy of the arc, it is v...

AI Technical Summary

Problems solved by technology

For the detection of arc faults using physical quantities such as arc light or temperature, since the sensors for detecting these parameters must be installed where the arc fault occurs, and the location of the arc fault is uncertain, this brings great difficulties to the comprehensive detection of arc faults in the power supply line. Inconvenience

In the existing arc fault detection technology, such as the patent "Arc Fault Detection Method and Protection Device", etc., respectively, whether the current amplitude of the protected circuit is smaller than the normal current amplitude, whether the positive and negative half cycles of the current waveform are symmetrical, and whether the waveform is Whether there is a flat shoulder at the zero point, whether the steep di / dt of the waveform is too large, etc., is practical to judge whether an arc fault occurs, but the detection method based on the change of the time-domain waveform of the protected circuit current cannot accurately distinguish The current waveform distortion caused by the arc fault and the current waveform distortion caused by some power electronic loads will cause misjudgment to a certain extent

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