Research And Design Of Factory Transmission Line Fault Location System

Nowadays, due to the continuous expansion of the scale of the factory, the length of transmission line becomes longer and there are more species. Once faults occur in the transmission line, the location of the point of failure must be found and repaired accurately and immediately from the complex line. Currently most fault location device used for transmission line are only point at fault location in close range, thus once the distance is long, it is unable to realize fault location. In order to solve the problem of function insufficiency of fault location equipment used in transmission line, this paper introduces the design of a fault location system of transmission line, with which both the near and the far away fault point can be located accurately, thus it improves the success rate of the fault location.First, this paper introduces the existing problems of transmission line fault location equipment. Then it analyzes and compares the domestic fault location methods with abroad, base on which it proposes the use of low voltage pulse reflection method to locate near fault point, and the use of Impulse voltage method to realize the location of remote fault point. At the same time, it combines online fault location method with off-line fault location method, which further improves the success rate of fault location. Finally,according to the theory of fault location method, it designs the overall structure of transmission line fault location system, which Include online and offline fault location device. And the main structure parts of the online fault location device and the off-line fault location device, such as sensor, pulse generator, high speed data acquisition module and the condition monitoring system of transmission line are analyzed and designed in detail. This paper designs a non-contact voltage sensor, which does not destroy the original structure of the circuit when it is used and the maximum frequency of thetraveling wave signal can reach 50 M. According to the difference of fault distance, the pulse source is divided into low voltage pulse source and high voltage pulse source. The low pressure pulse source is mainly controlled by the STM32 to output rectangular pulse signal, of which the highest frequency can reach 20 M, and the amplitude can reach15 V.The high voltage pulse source output high voltage signal using Marx circuit to breakdown metal ball and discharge to generate high voltage pulse signal, the amplitude of which can reach hundreds of volts. In order to accurately record the fault waveform,this paper uses the method of multiple data sampling in single channel to improve the sampling rate of ADC, using FPGA to control the process of AD sampling and data storage. In order to solve the problem of Inaccurate fault location of type C traveling wave fault location method in transmission line fault location with a branch line, this paper designs the condition monitoring system of transmission lines for the real-time detection of the voltage of all branch nodes, which sends the number of fault branch line to the host computer using the GSM module, and then analyzes and finds out the nearest branch node from the point of failure through the PC software, which can improve the success rate of the type C traveling wave fault location method.Finally, the fault location system is tested under laboratory conditions. According to the test results and the data, we can see that the fault location system designed in this paper realizes the fault location of both remote fault point and near fault point. The fault location accuracy of online fault location device can reach 5 meters. The fault location accuracy of offline low voltage pulse location device can reach 3 meters, and the fault location accuracy of offline high voltage pulse location device can reach 7 meters. And the retest results on the same fault are good.