Analysis of the discharge phenomenon inside the suspension clamp based on an overhead ground wire breakage case

• Published in: Electric power systems research Vol. 241; p. 111384
• Main Authors: Huang, Beisi, Liu, Gang, Wang, Rui, Lin, Xuan, Chen, Siting, Guo, Deming
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.04.2025
• Subjects: Discharge; Electric field intensity; Ground wire fracture; Lightning current; Suspension clamp; Suspension clamp; Electric field intensity; Lightning current; Discharge; Ground wire fracture
• ISSN: 0378-7796
• DOI: 10.1016/j.epsr.2024.111384

•When lightning strikes the ground wire, a discharge may occur inside the suspension clamp, causing damage to the wire strands.•When the lightning current flows into the clamp, the first contact point between the ground and the aluminum tape accounts for the largest percentage of the current.•The discharge that occurs inside the clamp is closely related to the shape of the contact points and the contact pattern.•A finite model has been developed for the analysis of the electric field distribution at a single contact point and the surrounding air gap. The Overhead Ground Wire (OGW) within a suspension clamp can suffer overheating and reduced mechanical strength under lightning currents, leading to fractures and posing short-circuit risks and public safety hazards. This paper discusses a 500 kV line accident where an OGW broke inside a suspension clamp. Through analysis of the accident site, mechanical properties of the damaged sample, and morphology of the damage site, the cause of the OGW fracture is preliminarily attributed to internal discharge within the suspension clamp. Finite element method calculations of the electric field intensity near the contact point between the OGW and aluminum tape under lightning current reveal high electric field strengths. These can exceed the air gap breakdown field intensity due to contact modes, potentially causing discharge. This study provides insights into the discharge mechanism within the suspension clamp, laying a foundation for further research.