The present invention relates to diagnostic device for the characterization of electromagnetic material properties and a method of making and using same. Unlike current diagnostic devices, the diagnostic device comprises a novel waveguide system and is suitable for the characterization of electromagnetic material properties such as permittivity, permeability, and the loss tangent of materials over a broad temperature and pressure range.

The invention relates to circuit arrangements for cable checking, cable testing, cable diagnosis and/or cable fault localization with a voltage source having a first voltage multiplier for a positive voltage and a second voltage multiplier for a negative voltage current sources that are connected to one another in combination with the voltage multipliers to generate a test voltage over the load impedance of the cable to charge and discharge the load capacitance of the cable and a control device that is interconnected with the voltage source and the current sources and
devices with a circuit arrangement of that type. The circuit arrangements distinguish themselves, in particular, by the fact that arbitrary voltage curves of different amplitudes can be generated through the cable as the impedance acting as the test specimen.

An apparatus for performing measurements on a utility power device that shares a common ground with the apparatus selectively sends a first high voltage signal via a first lead to a first terminal of the utility power device, measures a first corresponding signal returned via a second lead of the apparatus from a second terminal of the utility power device. While the corresponding first lead and the second lead of the apparatus remain electrically coupled to the corresponding first and the second terminal of the utility power device. The apparatus selectively sends a second high voltage signal via the second lead to the second terminal of the utility power device, and measures a second corresponding signal returned via the first lead of the apparatus from the first terminal of the utility power device.

An apparatus for performing measurements on a utility power device that shares a common ground with the apparatus selectively sends a first high voltage signal via a first lead to a first terminal of the utility power device, measures a first corresponding signal returned via a second lead of the apparatus from a second terminal of the utility power device. While the corresponding first lead and the second lead of the apparatus remain electrically coupled to the corresponding first and the second terminal of the utility power device. The apparatus selectively sends a second high voltage signal via the second lead to the second terminal of the utility power device, and measures a second corresponding signal returned via the first lead of the apparatus from the first terminal of the utility power device.

Method for evaluating dielectric losses, comprising: providing a HVDC electrical object (1) comprising: an electrical conductor (4) having a centre (C), an insulating layer (5); a metallic screen (6) and an outer sheath (7). The method comprising: applying an HVDC voltage making an electrical current flowing through the electrical conductor (4); computing a first heat flux (WC) exiting said electrical conductor (4) as function of an intensity of said electrical current; measuring an internal temperature (tin) and an external temperature (tou) by temperature sensors (10, 11) arranged at different radial distances from said centre; determining a thermal resistance (TR) of a portion of said components comprised between the first (10) and second (11) temperature sensors, computing a second heat flux (Fi) exiting said portion as a function of the thermal resistance (TR); computing dielectric losses (WD) of the insulating layer (5) as a difference between the second heat flux (Fi) and the first heat flux (WC).