Highly accurate current response measurements of insulation materials for HVDC applications

This paper presents a current measurement setup to determine polarization and conduction processes of solid insulation materials under HVDC stress. The setup enables simultaneous polarization, depolarization, and conduction current measurements of up to four material samples. The volume or surface current measurements are performed in a pressure vessel, adjustable to the whole range of possible long-term operating conditions present in gas-insulated equipment. Besides discussing the electrical and mechanical construction, this contribution addresses restrictions of the measurement range caused by an insufficient signal-to-noise ratio.