Evaluation and optimisation of insulator structural effectiveness based on the dynamic behaviour of arc across ribs

• Published in: Electric power systems research 2024-04, Vol.229, p.110169, Article 110169
• Main Authors: Yang, Hao, Song, Zhibo, Zhou, Fusheng, Hu, Wenxiu, Ma, Jianlong, Zhao, Sirui
• Format: Article
• Language: English
• Subjects: AC voltage; Creepage distance; Flashover; Insulator; Insulator rib; Partial arc
• ISSN: 0378-7796; 1873-2046
• DOI: 10.1016/j.epsr.2024.110169

•This study innovatively explores the impact of insulator ribs on arc paths, addressing challenges associated with pollution flashovers and arc bridges.•The research introduces flashover voltage gradients and creepage distances as metrics, providing a systematic evaluation of insulator performance and practical design guidance.•Practical recommendations for rib configurations, emphasizing specific ratios and alternating ribs, contribute valuable insights to prevent arc bridging and enhance insulator efficiency. Disc insulators serve as the primary insulating and supporting components in transmission lines. Pollution flashover incidents pose challenges for power practitioners. The disc insulator's ribs can improve the flashover voltage. However, pollution flashover are more likely to occur when there are arc bridges between insulator ribs. This study aims to investigate the impact of insulator ribs on the development path of arcs and flashover performance. The experimental circuit for flashover is constructed to analyze the arc's behaviour and evaluate the insulation performance. Utilizing flashover voltage gradients and creepage distances to evaluate the effectiveness of insulator structures. The insulator forms an arch hinge when two adjacent ribs are close in length, and the uneven air pressure within the arch hinge creates a thrust that causes the arc to break away from the surface and form a bridge. Maintaining a rib spacing to rib length ratio between 0.83 and 1.5 is recommended to prevent arc bridging. Alternating ribs improve creepage distance utilization, enhancing insulation with a recommended rib spacing to rib length ratio between 0.67 and 1.5. Avoiding low or high coefficient values is crucial to prevent arc bridging or inefficient insulator space use. The spacing between the insulator connector and the nearest rib should be more than the length of the rib, otherwise there is an increased likelihood of direct arcing connector the upper and lower umbrella skirts The spacing between the insulator connector and the nearest rib should exceed the rib length and the nearest rib to minimize the risk of direct arcing between the upper and lower umbrella skirts. The research content can provide a theoretical and experimental basis for improving the insulator structure and increasing its flashover voltage.