Risk Assessment Method of Overhead Line after Ice-shedding Under Ice and Wind loads

Due to the influence of temperature or human factors, ice-shedding may occur on ice covered transmission lines, causing wire jumping and unbalanced tension, which can lead to electrical or mechanical accidents. Conducting research on risk assessment methods of high-voltage overhead lines after ice-shedding is of great significance for preventing major ice disasters. The risk assessment method for ice-shedding of overhead lines under ice and wind loads was proposed in this paper. Firstly, the time series curves of vertical jump height, lateral swing and dynamic tension at the end of the transmission line are obtained under different ice-shedding modes. Secondly, the minimum inter-phase clearance of ice-shedding transmission lines, impact coefficient, the maximum unbalanced tension of suspension clamp and safety coefficient for the mechanical strength of the tension insulator strings are calculated through feature extraction. Then, the ratio $P_{1}, P_{2}, P_{3}$, and $P_{4}$ combining the above relevant characteristic parameters are obtained to analyze the risk of transmission line discharge, wire breakage, damage to suspension clamps, and damage to tension insulator strings. Finally, the risk assessment results of ice-shedding transmission lines are output by combining $P_{1}, P_{2}, P_{3}$, and $P_{4}$. The proposed risk assessment method can provide guidance for the operation and maintenance of the high-voltage overhead lines in heavy ice areas.