Multi-physics coupled temperature rise in GIS equipment with built-in optical fiber bundles

Abstract This study presents a novel multiphysics coupling analysis of a 220 kV gas-insulated switchgear(GIS)incorporating an embedded optical fiber bundle, with the key innovation lying in the systematic evaluation of the mutual compatibility between the integrated sensing system and the host equipment—an aspect rarely addressed in conventional GIS simulations.Using three-dimensional finite element modeling in COMSOL Multiphysics, the distributions of electromagnetic fields, thermal fields, and mechanical stresses are systematically investigated.Key findings reveal that: (1)the embedded fiber bundle induces only localized electric field distortion, approximately 1.3 × 10⁶V/m at the fiber tip, which remains well below the conductor surface maximum of 5.24 × 10⁶V/m, confirming preserved insulation performance; (2)thermal stress at the fiber-flange interface,4.3 × 10³N/m²,is orders of magnitude lower than the gigapascal-range compressive strength of silica, demonstrating adequate structural safety; and(3)under simulated abnormal contact resistance conditions, the maximum fiber bundle temperature reaches 344 K, utilizing only 68.8%of its continuous operating limit of approximately 500 K, indicating good thermal stability.This research provides a theoretical foundation and reliability assessment for integrating optical fiber sensing systems into high-voltage GIS equipment, supporting the advancement of intelligent substation technologies.