Space charges and life models for lifetime inference of HVDC cables under voltage polarity reversal

Abstract

HVDC cables connected to Current Source Converters are subjected to polarity reversal when the HVDC intertie changes the power flow. Mass Impregnated Non-Draining cables had been using since the dawn of HVDC transmission with Current Source Converters and over the years they have shown their own ability to withstand the overstressing electric field values that arise during a polarity reversal. Cable manufacturers give restrictions on the number of polarity reversal that a cable can sustain and furthermore they give procedures to pursue in order to preserve cable life under such conditions. A phenomenological ageing model under fast polarity reversal is illustrated in this paper giving some information about its parameters. Besides, a space charge measurement test method to be applied during laboratory tests on full sized cables is illustrated in line with the IEEE 1732 standard. Aim of this paper is to merge the two approaches since the outcomes of space charge measurements on full sized cables can help in the parameters inference of the polarity reversal ageing model.