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–POE checker
Cable failure is the most common power failure in power repair, and it is also more troublesome to detect. Although the use of cable flaw detectors has significantly improved the efficiency of cable fault detection, cable fault detection is carried out in some complex environments. Cable faults are the most common power faults in power repairs, and they are more troublesome to detect. Although the use of the cable flaw detector has significantly improved the efficiency of cable fault detection, the positioning accuracy of the cable flaw detector will also be affected by certain factors when performing cable fault detection in some complex environments.
So what are the factors that affect the positioning accuracy of the cable flaw detector? We all know that the resistance value of the fault point of the cable is the most important factor affecting the fixed point of the cable flaw detector, especially the low resistance fault of the cable, the more troublesome the fault point positioning. Because the smaller the resistance value of the fault point of the cable, the smaller the sound when the high-voltage signal generator is used for high-voltage impact, the more difficult it is for the locator to function, and the locator for metallic short-dead faults has no effect. The second is the cable laying environment. At present, most of the cable laying methods use the cable trench laying method, but the cable trench laying cable route is relatively short, and the cable flaw detector will be interfered by other cable lines when locating the fault point.
Or because the faulty cable is not threaded, if the fault point is discharged to the air, the pointing instrument is not easy to receive the sound signal. The last is the interference of the surrounding sound. We all know that when the cable flaw detector locates the fault point of the cable, the signal sound of the fault point is relatively weak, and a quiet environment is needed to monitor it. If the surrounding environment is too noisy, it will affect the fault. point of signal snooping. At present, the cable flaw detector is mainly affected by the above aspects when locating the fault point.
In order to ensure the accuracy of cable fault location, we should be patient and careful. The working principle of the cable fault locator: Since the propagation speed of electromagnetic waves is faster than that of sound waves, when the fault point is fired and discharged, the instrument first receives the electromagnetic waves and then receives the sound waves. Therefore, we can use the electromagnetic waves as the signal to open the door and use the sound waves to propagate the distance. S is the distance from the probe to the fault point. That is, the instrument starts timing when it receives the electromagnetic wave, stops when it receives the sound wave, and uses the time difference to calculate the distance from the probe to the fault point.
When the impact high-voltage discharge is performed, the electromagnetic wave sensor receives the electromagnetic signal radiated from the cable, sends it to the CPU for data processing, and starts the counter to start counting. When the acoustic wave probe receives the vibration wave, the data processor generates an interrupt signal, which makes the counter stop counting and displays the distance reading from the fault point to the probe. Some of the above related introductions about the factors affecting the detection of cable flaw detectors, I hope to be helpful to all friends.
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