In recent years, due to the support of the national policy for the broadband industry, the ADSS optical cable industry has developed rapidly, which has been accompanied by many problems. In addition, domestic optical fiber manufacturers will face more severe challenges.

The following is a brief description of the test method based on the fault point resistance:

1. When the resistance of the fault point is equal to zero, it is easy to find short-circuit faults by measuring the low-voltage pulse method, but such faults are rarely encountered in actual work.

2. When the resistance of the fault point is infinite, it is easy to find the open circuit fault by measuring the low-voltage pulse method. Generally speaking, pure open circuit faults are not common. Usually open circuit faults are relative to ground or phase-to-phase high resistance faults, and relative to ground or phase-to-phase low resistance faults. Obstruction failures coexist.

3. The flashover fault can be measured by the direct flash method. This kind of fault generally exists inside the joint. The resistance at the fault point is greater than 100 kiloohms, but the value changes greatly, and each measurement is uncertain.

4. When the resistance of the fault point is greater than zero and less than 100 kiloohms, it is easy to find the low-resistance fault by measuring the low-voltage pulse method.

5. The high resistance fault can be measured by the flash-over method, and the resistance at the fault point is greater than 100 kiloohms and the value is determined. Generally, when the test current is greater than 15 mA, the test waveforms are repeatable and can overlap, and one waveform has one emission, three reflections and the pulse amplitude is gradually weakened, 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.