A Study Of The Intelligentization Of Cable Faults Detecting Technology

Power cable has been becoming the important foundation of modern industrial civilization, and has been replacing the traditional overhead line gradually, so it has a close relationship with industrial and agricultural production as well as our daily life. But the great financial losses caused by unavoidable cable faults has became a serious problem in society nowadays. How to detect the cable fault points in complicated laying environment quickly, effectively, and accurately has a very important significance.Firstly the paper introduced the reason cable faults and faults’ types after consulting a large number of literature, then considered the TDR theory as this paper’s basic designing reference on the foundation of analyzing and comparing the common method of detecting cable faults. After that introduced cable wave propagating theory briefly as well as wave propagating speed、wave impedance and wave reflection phenomenon and refraction phenomenon under the long-line pattern. On the condition of comprehensive consideration about these factors, pointed the specific technical indicators as well as relevant hardware circuit and software algorithm process of a cable fault tester, which plays a important role in intelligent cable fault detection. With embedded microcontroller and CPLD as its core, the system’s hardware circuit also consists of hardware circuit modules such as pulse sending module、signal receiving module and high-speed ADC sampling etc. The system’s software algorithm consists of embedded C programming language of microcontroller and Verilog HDL of CPLD. The structure of the former is modularization while the structure of the latter is Top-Down. Because of the complex testing environment and so many kinds of interference sources, the we got usually has many irregular vibration, which affects recognizing useful fault information and calculating the distance of cable fault seriously. Under this background this paper also did some primary research about intelligent reflected wave processing technology. This paper then analyzed and compared the three classical kinds of methods of smoothing based on maximum principle、relativity principle and threshold value theory on the basis of wavelet analysis theory. After that the paper discussed some key factors which has an importantinfluence on smoothing effect such as how to select threshold function、quantitative criteria of threshold value、wavelet function and floors of wavelet decomposition. Finally the paper selected db4 as its wavelet function and soft threshold function as its threshold function.At last this paper used MATLAB did some simulation experiment about actual smoothing effect based on db4 wavelet function, then also did some simulation experiment with some authentic information got in Kun Shan by using the cable fault tester designed in this paper, and the result proved it did a good work, meanwhile the cable fault tester designed in this paper also did a good work in detecting cable fault, and had a acceptable error. All of these proved the paper got some success in intelligent cable fault detecting.