A METHOD OF ESTIMATING THE LOCATION OF A CABLE BREAK INCLUDING A MEANS TO MEASURE RESISTIVE FAULT LEVELS FOR CABLE SECTIONS

摘要

A method and apparatus are used for locating cable breaks and resistive faults in cables, including fibre optic cables. The conductive shield or armour of the cable is divided into sections, usually at a splice. A step function voltage is applied to one end of the conductive shield. Remote sensors at the end of each secti on monitor the voltage and current as a function of time and at steady state. T he measured data are encoded as current pulses and transmitted along the armour to the end of the cable. A computer at the cable end calculates from the measur ed voltages and currents the capacitance of each section of the shield. A broke n section is identified by comparing the calculated and original capacitances of the sections and the distance along the broken section to the break is calculate d from the calculated and original capacitances of the broken section. Resistive faults in the cable are located by calculating a fault resistance of each section of t he shield from the measured steady state voltages and currents. A section containing a resistive fault is identified from the magnitude of the calculated fault resistance and the distance to the resistive fault is calculated from the measured steady state voltages and currents of the faulted section.