Framework for Analysis of Accelerated Aging of Oil-Paper Insulation Systems under Harmonic Voltage Stresses

Inhalt:
Prolonged operation of oil-paper insulation systems under high AC voltage distorted by MF-frequency harmonic distortions can lead to accelerated aging of the system and consequently to a reduction in its operational lifespan. Voltage harmonics represent a significant concern primarily attributed to switching power-electronic-based equipment. Oil-paper insulation systems are still extensively used within high-voltage capacitors and various transformer types, such as AC power transformers and HVDC converter transformers. Prior studies have extensively examined the influence of conven-tional stresses such as AC, DC, and surge voltages, as well as characteristic, low-order harmonic voltages on their dielectric properties. However, a notable gap exists in research concerning the consequences of extended exposure of these insulation systems to AC voltages distorted by high-order harmonic voltages and its implications for insulation lifespan. This paper presents a framework for accelerated aging of the oil-paper system under long-term operation under AC voltages distorted by high-order voltage harmonics, with a focus on the selection of aging conditions and duration. The discussed aspects include the design of the device under test design, electrode arrangements along with the test vessel, moisture control in aged samples, and the layout of a test system for generating harmonically distorted voltages in a dedicated setup.