Patent ID: 6498499
Filing Date: 2002-12-24
Classification: G01R

Abstract:
A device for measuring the capacitance of electrical cables having an inner conductor and an insulating cover, the device comprising at least a first measuring tube of electrically conductive material having a first length and at least a second tube located coaxially with respect to the first tube and having a second length which is significantly smaller than the first length, both measuring tubes being adapted to be connected to a measuring voltage source of high frequency, the cable being moved through first and second tubes, a screening tube which surrounds said measuring tubes in radially spaced relationship and being also adapted to be connected to the voltage source, water located between said cable and the measuring tubes, a first capacitance measuring means which measures the capacitance between said first measuring tube and said conductor and a second capacitance measuring means which measures the capacitance between said second measuring tube and the conductor, both the first capacitance measuring device and the second capacitance measuring device simultaneously measuring the capacitance of the respective lengths of cable surrounded by the first and second measuring tubes and wherein differences between the measured capacitance of the first and second capacitance measuring means indicate local changes of the capacitance of the electrical cable.