In recent years, with the support of national policies for the broadband industry, the ADSS fiber optic cable industry has developed rapidly, which has been accompanied by numerous problems.
The following are the briefly describes of five testing method based on the resistance of the fault point:
1. When the resistance of the fault point is equal to infinity, it is easy to find the open circuit fault with the low-voltage pulse method. Generally speaking, pure open circuit faults are not common. Usually open circuit faults are relatively ground or phase-to-phase high-impedance faults, and relatively ground or phase-to-phase low The coexistence of resistance faults.
2. When the resistance of the fault point is equal to zero, it is easy to find the short-circuit fault by measuring the short-circuit fault with the low-voltage pulse method,but it is rarely encountered in actual work.
3. When the resistance of the fault point is greater than zero and less than 100 kilohms, it is easy to find low-resistance faults by measuring with the low-voltage pulse method.
4. Flashover faults can be measured by the direct flash method. Such faults generally exist inside the connector. The resistance of the fault point is greater than 100 kilohms, but the value changes greatly, and each measurement is uncertain.
5. High-resistance faults can be measured by flash-flash method, and the fault point resistance is greater than 100 kilohms and the value is determined. Generally, when the test current is greater than 15 mA, the test waveforms are repetitive and can overlap, and a waveform has one emission, three reflections and the pulse amplitude gradually decreases, the measured distance is the distance from the fault point to the cable test end; otherwise Test the distance from the fault point to the opposite end of the cable.