Underground cable fault locator using induction - has HV generator modulated by audio tone to aid detection by prodn. of spark discharge at fault

摘要

The underground cable fault location system is suitable for cables both with and without exterior metal sheathing. The equipment uses a conventional high-voltage test source with which a spark discharge is produced at the site of the cable fault by voltage breakdown between the conductor and earth. The high-voltage tester can use DC or low-frequency AC. Added to the high-voltage source is an audio-frequency generator which modulates the HV generator. A portable pick-up coil connected to an audio-frequency receiver is used to locate the site of the cable fault by detecting the presence of the modulated noise from the arc discharge in the cable.