The Key Technology Research And Application On Arc Fault Detection

The electric circuitries will be easy to cause arc fault and initiate electrical fire if the electric circuitries and equipments overload long time or have poor electric connection. When the line occurs arc fault, the scale of arc fault current is too low to be detected by protection devices. AFCI (Arc Fault Circuit Interrupters) could protect circuit from arc fault. Its main function is cutting off the circuit and protecting the circuit from the electrical fire when the arc fault occurs in the circuit. AFCI could reduce lots of electrical fires which are caused by arc fault effectively.The main work of this dissertation includes:Firstly, this thesis introduces the background of arc fault, the lately study and the future of the arc fault protection, then it illustrates the main research contents, tasks and some problems. It also illustrates the knowledge about arc fault and the basic structure of AFCI.Secondly, the thesis elaborated3kinds of arc fault detections in domestic and international, and then compares their advantages and disadvantages. It mainly describes the applications of Fourier transform and the wavelet transform in the signal detection field. Finally, it proposes a kind of arc fault detection method based on Daubechies4orders wavelet transform.Thirdly, the experiment is conducted to collect arc fault data under a variety of loads in a platform of arcing according to UL1699standard and an arc fault database is established. Then the kind of arc fault detection method based on Daubechies4orders wavelet transform is proved by data processing in Matlab software.At last, the thesis emphatically introduces the design of AFCI’s hardware and software. Then the thesis summarizes the measures to improve the subject and describes the prospect of the AFCI.AFCI is based on massive arc fault experimental data and designed for the domestic220V low voltage single power distribution system. The AFCI which according to this thesis has the advantages of small volume, convenient installation, high resolution and integrates electric leakage protection function. It keeps the voltage distribution lines, the electric equipments and persons safe.