Device and method for measuring space charge in an electric cable specimen

Abstract

A device (10) for measuring space charge in a high-voltage direct current electric cable includes a DC voltage source (12), a voltage step generator (14), a first electrode (16) connected to the DC voltage source (12) and to the voltage step generator (14), a second electrode (18) that is grounded, a piezoelectric sensor (20) connected to the second electrode (18), an electrical-signal amplifier (22) connected to the piezoelectric sensor (20), and at least one specimen (24) of the electric cable placed between the first and second electrodes (16, 18) and including a cut of the cable made to a predetermined depth in the electrical insulation system of the cable. The amplitude of the signal measured at the output of the amplifier (22) is related to the charge density in the specimen (24) and the delay related to the distance of the charges from the piezoelectric sensor (20) giving the position of the charges.

Dependencies are inferred from the claim text.