The Study Of Arc Fault Recognition And Protection Methods

With the improvement of China’s economic level, people are increasingly demanding high quality of life and also attaching more and more attention on the quality and safety performance of household appliances. As product quality or human improper operation and other reasons, appliances malfunction causing the gradual increase in the frequency of the electrical fire, which is becoming increasingly serious harm to people’s lives. Overheating and arc are traditionally two types of electric fire, mainly due to leakage, short circuit and over load. Of all the Existing electric protection systems, various relays and circuit breakers are able to identify the leakage, short circuit, overload and other causes of overcurrent or overvoltage, timely response to protection and preventing the overheating type electrical fire from happening effectively. Due to the features of arc fault current is small, high temperature and short duration, etc, it is difficult for the relays and circuit breakers in the existing protection of the line to identify. Therefore, the study of arc fault, looking for effective arc fault detection and identification methods, research and development for the electrical characteristics of arc fault circuit breaker has the vital significance.Because of different domestic and low-voltage distribution environment, foreign countries’ formed arc fault detection methods and testing standards are not entirely suitable for our country.This paper will make a reach on the arc fault technology on the benchmark of domestic low-voltage distribution environment and build an arc fault test platform based on UL1699 standard. It will load typical test data collection, use MATLAB simulation and analysis, study characteristics of arc fault, put forward improved fault arc detection method. On the base of the characteristic of the arc fault and the analysis of the simulation results, this paper puts forward the methods and the criterions of arc fault detection and develops the arc fault circuit breaker on this basis.This paper paies much attention on the analysis and research on the arc fault detection and uses the fact that arc fault current contains more high frequency harmonic, putting forward a new way to detect wavelet transform fault arc. The frequency spectrum will aliasing during the original wavelet transform in the wavelet decomposition and reconstruction process and greatly reducing the accuracy of detection. Based on the original wavelet transform, this paper will add odd nodes before extraction and combined it with an even extraction, presents an improved algorithm of wavelet transform spectrum aliasing resistance on the base of adding a node before extraction and eliminate the spectral aliasing phenomenon. Formulating series arc fault detection method according to the improved wavelet transform algorithm and based on this detection method, designing the hardware and software of the arc fault circuit breaker and completed the final design. This paper conduct the leak and misoperation test for the development of arc fault circuit breakers, the test results show that the proposed development of arc fault circuit breakers can accurately detect the arc fault line and accurately distinguish normal arc and arc fault timely and insure the normal operation of the lines and equipment.