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 Monitor Tester
Power cable fault point location and high resistance cable fault location method Power cable fault point location Power cable fault and high resistance cable fault are both common problems of cable faults, and they are also medium and high frequency problems of cable faults. Power cable fault location and high-resistance cable fault location method Power cable fault location Detection, cable fault finding, cable fault location, high-voltage cable fault detection, etc. For details, please log in: http://www.gdbndz.com/ Power cable faults and high-resistance cable faults are common problems of cable faults, and also belong to medium and high cable faults. The following editor analyzes and writes the methods for locating the cable faults of the two, hoping to have a certain reference for everyone when they encounter cable faults. Power cable fault location method: In view of the problem that it is more difficult to determine the location of the fault point after the failure of the buried power cable than the overhead line, a representative example of the location process of the fault point when a high-resistance fault occurs in the 10 kV cable is selected. According to the nature of the fault, the method of using the secondary pulse method to locate and locate the fault point is introduced. For high-resistance faults that occur during the operation of the cable, first check the relevant information of the cable to master the detailed information of the cable; use a multimeter and an insulation resistance meter to determine the type of cable fault, and determine the corresponding test method according to the type of fault; use a fault tester to test the cable's fault. Length, check whether the test results are consistent with the data, and preliminarily determine the distance of the fault point; finally, the secondary pulse method is used to accurately locate the fault point to find the fault point, strip the cable to find out the cause of the cable fault, so as to take corresponding preventive measures.
This method is easy to master, especially for short-distance faults, the test waveform is easier to analyze, the fault distance can be quickly determined, and the cable testing efficiency is higher, and the fixed-point positioning time is shorter. Power cable faults are complex and diverse, and can be divided into open faults and closed faults according to the surface phenomenon of the fault; according to the grounding phenomenon, they can be divided into ground faults, interphase faults, and mixed faults; according to the fault location, they can be divided into joint faults and cable body faults; according to the nature of resistance It is broken line fault, mixed line fault and mixed fault, among which, mixed line fault is divided into low resistance fault, high resistance fault and flashover fault. 1. Fault detection methods For different cable faults, the usual detection methods include low-voltage pulse method, pulse current method, secondary pulse method, bridge method, pulse voltage method, etc. [3], this article only introduces three commonly used detection methods .
2. Low-voltage pulse method The low-voltage pulse method is suitable for detecting low-resistance faults (fault resistance is less than 200ΩIt can also be used to measure the length of the cable, the propagation speed of electromagnetic waves in the cable, and distinguish the intermediate head, T-joint and terminal head of the cable. 3. Pulse current method The pulse current method generally includes the impulse flash method and the direct flash method. The linear current coupler is used to collect the current traveling wave signal in the cable, and the fault test waveform diagram is generated, so as to realize the fault condition and measure the fault point distance through the waveform. Purpose. The direct-flash method is used to detect flashover breakdown faults, that is, the resistance at the fault point is extremely high, and when the voltage is raised to a certain value with high-voltage test equipment, a flashover breakdown fault will occur.
The rush-flash method is also suitable for testing most of the flashover faults. Since the waveform of the direct-flash method is relatively simple and it is easy to obtain more accurate results, the direct-flash method should be used as much as possible. 4. Secondary pulse method With the cooperation of high voltage signal generator and secondary pulse signal coupler, secondary pulse method can be used to measure the fault distance of high resistance and flashover faults. The waveform measured by this method is simpler and easy to identify. The method of power cable fault location and high resistance cable fault location Shenzhen Noyafa Electronic Technology Co., Ltd.
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