Research And Implementation On Low-voltage Arc Fault Circuit Interrupter

Arc fault may occur at electrical wiring and equipment in house whose cable insulation hasbeen old or even damaged because of long-run overload or bad electrical connections, When arcfault occurs in a power line, the load current is usually small while the temperature of burning arcwas up to several thousand degrees, that can ignite any surrounding material to cause electrical fires.So arc fault has become one of the important causes of electrical fires.AFCI (Arc Fault Circuit Interrupter) technology is a new power line protection technologywhich can disconnect the line in time to avoid an electrical fire when arc fault occurs. InstallingAFCI in the terminal of power distribution lines can the timely detect the arc and cut off the circuit,which is effective measure to reduce losses of electrical fires caused by arc fault. But in the currentlow-voltage power distribution system, the widely-used traditional circuit breakers do not have thefunction of arc fault detection.The purpose of this thesis is to study arc fault detection technology and design arc fault circuitinterrupter for low-voltage distribution system environment. Around this purpose, mainly work todo as follows:Research background, research status and prospects are introduced, the basic causes andprocesses of arc is discussed from the point of physics and circuit theory ,then the basic dynamic arccircuit circuit is analysized.The experiment is conducted to collect a large number of repetitive tests arc fault signal andestablish arc fault test database.Through analysing the fault current signal, typical characteristics ofarc are summarized as follows: "current zero off" phenomenon, "Current zero off "after the currentmutation, near the peak of the high-frequency harmonics, continuous periodic damage, waveformasymmetry. Beside, characteristics analysis of zero sequence current of arc fault signal isexplored.Compared signal analysis of the arc line current in the time domain and frequency domain,respectively, arc fault detection method based on lifting wavelet is proposed.Integrated arc fault detection method is proposed in which typical typical characteristicsdetection in line current and detection method based on lifting wavelet are included.Finally,AFCIbased on embedded control systems is designed,including hardware design and software codewriting and optimization, and production of the actual product samples. Refer to UL1699 standards,hardware and software of arc fault circuit interrupter is tested for a variety of system malfunction.The results of the experiment achieve the desired design goal.