SYSTEM AND METHOD FOR DETERMINIG CABLE FAULT LOCATIONS OR AREAS IN AN ELECTRIC HEATING CABLE

摘要

Method for determining cable faults in an electric heating cable comprising at least two well conductor lines having an electrical resistor material in between them and electrically connected to the conductor lines in order to dissipate power over mainly the whole length of the cable when connected to an electric power source. Such cable fault may be caused by electrical disconnection between the resistor material and the conductor lines, resulting in interruption of the power dissipation there. The method comprises the steps of a. sending an electrical signal having a predetermined electric power PA, from a location A to a location B of the cable and determining the power PA' of the signal arrived at location B, b. sending an electrical signal having the predetermined electric power PA, from location A at a moment T1, as well as sending an electrical signal in the opposite direction having a predetermined electric power PB from location B at a moment TB which is chosen such that the first signal and the opposite signal meet each other at a predetermined location C between the locations A and B, and determining the power PA" of the signal arrived at location B, c. comparing the power PA" of the signal arrived at location B determined in step b. with the power PA' of the signal arrived at location B determined in step a. and concluding either that if PA" is lower than PA', location C is not faulty, or if PA" is not lower than PA', location C is faulty.