Insulation testing of mining HV cables - using evaluation circuit connected via timer-controlled relays

摘要

An arrangement for testing the insulation of h.v. power cables in underground mining installations applies a d.c. voltage comparable to the operating voltage to the cable when out of circuit. It contains a timing circuit and an evaluation circuit extracting signals dependent on the insulation resistance. The arrangement is relatively economical compared to conventional devices. The circuit is connected both to the h.v. supply associated with the cable and to the cable itself when out of the supply circuit. It contains a surge current circuit with a rectifier circuits and circuit breaking switches controlled by a timing circuit. The evaluation circuit inputs are connected to the cable so that the circuit can measure the voltage on the cable.