Study on the influence of charged glaze on the corona onset voltage of bundle conductor

Glaze grows on the conductor surface will affect corona onset voltage (COV). Wires iced under voltage is often neglected and scaled models always adopted to study the actual bundle conductors, there is no lights have been thrown into the down-trend of COV during charged icing. AC corona tests of iced bundle conductors implemented in the Multifunction Climate Chamber, the UV imaging camera and I-U curve fitting applied to analyze the COV. Finite element models of iced conductor established to discuss how the glaze icicles affect electric field. Results show that glaze cut the COV down greatly. Different icicle morphology leads to distinct COV values. With more sub-conductors, bundle conductor gets higher COV in the same icing time. With the Increase of icing time, COV decreases with the rate slow down. Higher conductivity has no effect on morphology but reduces the COV. Sharper icicles lead to more seriously field distorted and lower COV values. This paper provides reference for selection and designation of transmission line in glaze icing areas.