LOCATION OF HIGH RESISTANCE GROUND FAULTS ON BURIED POWER-CABLES

摘要

The location of high resistance ground faults within buried co-axial power cables can be detected by transmitting a combined signal along the cable at a primary frequency of 0.718 Hz and a primary amplitude in the order of 4,500 volts peak to peak, This combined signal also has an interlocked secondary frequency of 11,780 Hz superimposed on the primary frequency. The ratio between the reactive impedance and resistive impedance is such as to create a condition where the 0.718 Hz primary frequency's single source caused resistive current is usually larger than the sum or total of all that cable's per foot of length's 0.718 Hz reactive currents. This condition then enables the detection of the resistive ground faults by a manually transported Receiver. When needed the effective resistance and/or capacitance of the cable can be increased by a remote end connection circuit.