Study on the effects of glaze icing on the corona onset characteristics of stranded conductors

Glaze affects corona onset voltage (COV) after icing on the conductor surface. Energized icing on operating wires is always ignored in many tests, and the COV downtrend has not been elucidated. A series of AC corona tests on stranded conductors after energized icing are implemented in the multifunction climate chamber, and the UV imaging camera and I-U curve fitting method are applied to measure and analyze the COV. Finite element models are established to research the effect of glaze icicles on the field strength of conductors. Results show that glaze significantly reduces COV, with different glaze shapes leading to distinct COV values. Wires with thick radius receive high COV even when such wires are iced under the same duration. An Increase in icing time slows the decrease rate of COV values. High conductivity decreases COV and slightly changes the glaze morphology. Sharper icicles correspond to more serious field distortions and lower COV values. This paper provides a reference for the selection and design of transmission lines in glaze icing areas.