Research Of The Cable Fault Gathering System Based On TMS320LF2407A

With the development of city and rural electric power network, the possibility of the cable fault accurate is also becoming more and more greatly. How do category and location of cable fault is ascertained quickly and accurately, for power system quality improvement of cable and reducing the economic loss to being the very influential role. The mature technology for cable fault location is mostly based on off-line at home and abroad. There are not efficient methods for cable fault location on-line, so this topic has an exigently realistic significance. This dissertation focuses on applying wavelet analysis to detect the time faults occurred, to gather cable fault and to calculate faults'distance of cable.At first, this dissertation introduces the theories of wavelet, the singularity detection theories of wavelet analysis. The wavelet is applied cable fault location from the multi-scale analysis and module maximum, the wave course of transmission is introduced, the effect of coupling among three phase lines can be solved by phase-mode transform. The echo and refraction of traveling waves at the discontinuous spot of impedance, such as fault point or bus bar, are analyzed Aiming at the problem of the uncertainty of wave speed which influence the accuracy of location, fault distance expression that avoid the wave speed influence in theory are worked out, and model the cable fault by using EMTP software. simulation show that the wavelet transform can effectively analyze the transient traveling wave, and be immune to the fault location, fault type and transition resistance, and enhance the accuracy of location.Then the designing and application of the hardware and software of cable fault location system are performed in this paper. The hardware designing includes there parts: The first one is the signal adjustment circuit which is made of the current transformer and operational amplifier; The second one is high-speed sampling circuit which uses the TMS320LF2407A as the main center processing unit; The third one is PC computer as the upper computer of system. The software designing includes two parts: The first part is the front computer procedures which are compiled by C and assemble language that can achieve many works about system initialization, interruption acquisition, displaying data and transmitting data. The second part is the upper computer procedures which are compiled by VC language and EMTP that can accomplish some assignments about real time transmission of data, image-based rendering, file saving, wavelet analysis and data bank development.Finally, the system is tested in this paper. The test results show that the hardware and software can normal work and meet the requirements of cable fault location on line.