Author: Noyafa–Cable Tester Manufacturer
The burn-through wire tester at the fault point of the cable takes advantage of the three changes and one strengthening of the insulation monitoring, and the faults that occur in the operation of the cable are gradually reduced, while the faults that are aware of in the preventive test are relatively abundant. The resistances of the fault points tested for breakdown are all very high, and most of them are high-resistance faults. According to the statistics of the organization, more than 90% of the cable faults caused by preventive test breakdown are high-resistance faults, and the faults generated during the operation of the cable also account for more than 60% of the high-resistance faults.
However, the bridge method or audio induction method must be used for measurement under low resistance conditions. For this reason, the high-resistance fault should be extended to burn-through processing, so that the high-resistance becomes a low-resistance to facilitate the measurement. As measured by the bridge method, the fault resistance value is required not to exceed 2kΩ, up to 100kΩ; Apply the low-voltage electrophoresis reflection method, and the fault resistance is required to be no more than 100Ω;Use the beat induction method to ensure that the resistance is not higher than 10Ω;Apply the sound measurement method, the fault resistance should be within 1kΩabout. The resistance value of the fault point after burn-through should meet the requirements of different measuring instruments.
There are two types of solutions for burning through the fault point of the cable: AC burn-through and DC burn-through. During AC burn-through, it is required to provide reactive current to the faulty cable, so the capacity of the burn-through equipment must be large enough. In addition, when AC burn-through is used, because the power-frequency photoelectric needs to pass through two zero points in one cycle of power frequency photoelectricity, the insulation is stabilized at this time, and the fault resistance is added quickly, so that the fault point is easy to be blown out.
Therefore, when it is not necessary to burn the fault point resistance down to as low as 100ΩWhen it is down, it seems that the AC burn-through method is not used. Burn-through wire tester for cable fault point Shenzhen Noyafa Electronic Technology Co., Ltd.
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