Research On Arc Fault Detection Device Based On Wavelet Transform Theory

With the rapid development of China,s economy,various electrical equipment are constantly emerging in the home,business and industry.The electrical fires caused by electrical line faults are also getting higher and higher,which brings great harm to people 's property and life safety.In recent years,domestic and foreign scholars have conducted in-depth research on electrical circuit arc fault theory and detection devices,which become an important research direction in the electrical field.Arc fault are generally classified into three categories:series arc fault,parallel arc fault,and ground arc fault.Generally,the fault current is large when the parallel arc fault and the ground arc fault occur.The traditional electrical protection equipment can effectively protect.When the series arc fault occurs,the series fault arc current is smaller than the short circuit and overload threshold set by the traditional electrical protection equipment.Electrical protection equipment cannot effectively prevent electrical fires caused by series arc fault in electrical circuits.Therefore,it has great theoretical and practical significance to study series arc fault and the method of detecting arc fault.This paper proposes a wavelet transform arc fault detection method based on the combination of time domain and frequency domain.The method firstly uses the time domain periodic energy analysis to calculate the energy value per half cycle current,and then calculates the ratio of the energy value at the time of failure to the energy value at normal time,and obtains the threshold value as the criterion for detecting the arc fault 1;then uses the db3 wavelet The transformation theory is used to extract the high-frequency signal of the arc fault.The Mallat algorithm is designed to decompose the signals of different frequency bands,and the characteristic value of the arc fault is derived as the criterion for detecting the f arc ault.Finally,the two criteria of time domain and frequency domain are combined.Therefore,the electrical circuit series arc fault is effectively discriminated.The method fundamentally solves the problem of poor adaptability of the traditional arc fault current zero-crossing detection load,and expands the application range of the arc fault detection.Based on theoretical analysis,this paper studies an arc fault detection system based on ARM chip STM32F405.The hardware part of the arc fault detection system mainly includes:ARM minimum control system,power module circuit,current detection and conditioning circuit,CAN communication circuit and sound and light alarm circuit.The software part of the system mainly includes:current signal acquisition subroutine,fault arc detection subroutine,sound and light alarm and CAN communication subroutine.Finally,an arc fault experiment platform composed of a simulated arc fault main circuit and an arc fault detection system 1s built according to the UL1699 standard.The experimental study on the arcing of various electrical loads such as resistor load,resistor-inductance load and special load is carried out on the experimental platform.It 1s verified that the proposed method based on wavelet theory arc fault detection method has better detection method than traditional arc fault current zero-crossing detection method.More extensive load adaptability and effectiveness.