Scholarlink

This case study investigates cracking failures in Gas-Insulated Transmission Line (GIL) clamps at the China Nanyang Ultra-High Voltage (UHV) Station. Between May 2021 and March 2022, 118 out of 145 clamps developed cracks at the fillet welds, mainly near the stiffener plates. Initial theories proposed that the failures were a result of excessive bolt torque during installation. However, newly installed clamps, tightened to the standard torque of 90 N·m, also cracked within days, prompting a comprehensive investigation. The analysis encompassed material testing, penetrant inspection, torque compliance checks, and finite element simulations. The results revealed structural design defects in the clamps, leading to significant stress concentration at the fillet welds, which exceeded the yield strength of the 5083 aluminum alloy under standard torque. Vertical clamps experienced higher stress levels due to their asymmetric layouts. The recommendations call for a structural redesign to reduce stress concentrations and a reevaluation of torque specifications. This research provides practical insights for enhancing the reliability of UHV GIL shell structures.

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Clamp Cracking Failure Analysis of UHV GIL Pipeline Shell Structures Under Outdoor Thermal Environment

  • 会议论文

  • 发表日期：

    2025年

查看全文
  • Yong-Feng Zhao,
  • Jun-Li Du,
  • Jin-Hao Niu,
  • Chao Li,
  • Liu-Bin Zhang

摘要

This case study investigates cracking failures in Gas-Insulated Transmission Line (GIL) clamps at the China Nanyang Ultra-High Voltage (UHV) Station. Between May 2021 and March 2022, 118 out of 145 clamps developed cracks at the fillet welds, mainly near the stiffener plates. Initial theories proposed that the failures were a result of excessive bolt torque during installation. However, newly installed clamps, tightened to the standard torque of 90 N·m, also cracked within days, prompting a comprehensive investigation. The analysis encompassed material testing, penetrant inspection, torque compliance checks, and finite element simulations. The results revealed structural design defects in the clamps, leading to significant stress concentration at the fillet welds, which exceeded the yield strength of the 5083 aluminum alloy under standard torque. Vertical clamps experienced higher stress levels due to their asymmetric layouts. The recommendations call for a structural redesign to reduce stress concentrations and a reevaluation of torque specifications. This research provides practical insights for enhancing the reliability of UHV GIL shell structures.