Partial discharge measurements on a high voltage direct current mass impregnated paper cable

Partial discharge measurement has been a good tool for the quality assurance of power cable insulation under alternating voltage. With the growing interest in HVDC power cables, it therefore seems logical to extend this technique for use at direct voltage. The paper describes this technique as used on a HVDC cable with mass impregnated paper. The different phases of operation (no load, full load, cooling phase, etc.) are characterized by a different discharge behaviour. Special attention is given to the dangerous cooling phase. Models have been developed which can explain the discharge patterns that were measured. This paper gives an insight in the electrical behaviour of a HVDC cable with mass impregnated paper insulation