NOYAFA Electronic specializing in testing instruments and cable testers for 16 years
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NOYAFA Electronic specializing in testing instruments and cable testers for 16 years
Author: Noyafa–CCTV Tester
Question: What is the traveling wave method for cable fault location? Answer: The research on the traveling wave method in cable fault location started in the early 1940s. It is based on the traveling wave transmission theory to realize the transmission line fault location. . Now the traveling wave method has become a hot research question: what is the cable fault distance measurement? Answer: The research on the travel wave method distance measurement in the cable fault location started in the early 1940s. It is based on the traveling wave transmission method. Theoretical realization of transmission line fault location. Now the traveling wave method has become a research hotspot.
(1) The early traveling wave method can be divided into three categories: A, B, and C according to the principle of fault location: ① A-type fault location device uses the traveling wave generated by the fault point to reach the bus end and then reflects to the fault point, and then the fault The distance to the fault point is determined by the time difference and the traveling wave speed of the point reflection reaching the bus terminal. However, this method does not solve the problem of distinguishing the reflected wave at the fault point from the transmitted wave of the reflected wave at the opposite busbar end at the fault point, so it is difficult to implement. ② The B-type fault location device uses the recording of the time when the traveling wave generated by the fault point reaches the two ends of the line, and then realizes the distance by means of communication.
Since this distance measuring device uses the information of the first traveling wave reaching the bus terminal after the fault occurs, there is no problem of distinguishing the reflected wave at the fault point and the transmitted wave of the reflected wave at the opposite bus terminal at the fault point. But it requires a communication link at both ends of the line, and the time scale on both sides should be consistent. This requires the use of GPS technology to achieve.
③ The C-type fault location device is to transmit high-voltage high-frequency or DC pulses from the device after the fault occurs, and to measure the distance according to the time that the high-frequency pulse travels from the device to the fault point once. This distance measuring device is simple in principle and high in precision, but requires additional components such as a high-frequency pulse signal generator, which is expensive and complicated. In addition, it is often difficult to distinguish the reflected pulse of the fault point from the interference during distance measurement, and three phases of the transmission line are required to have high-frequency signal processing and carrier channel equipment.
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