3-D Simulation of thermal stress for EHV GIS (Gas Insulated Subsystem) Busbar

The Extra High Voltage (EHV) Gas Insulated Switchgear (GIS) plays a vital role in power networks, designed to meet the significant need for enhancing the compactness and reliability of substations. The security and reliability of GIS has direct impact on smooth operation of power systems. The GIS mainly use SF6 gas because of its arc quenching properties and high dielectric strength. Nonetheless, a critical issue affecting Gas Insulated Switchgear (GIS) is the excessive heat generated in the busbar connection components, circuit breakers, and isolating switch contact components, significantly impeding the progress of GIS technology. Typically, the ampacity of the busbar is restricted by the highest permissible operating temperature, a factor that must be anticipated in accordance with the requirements outlined in the IEC 6227 standard. Firstly, A Three Dimensional model of sub-aspect bus in GIS is built to calculate Multiphysics fields including electromagnetic field, flow field and thermal field in steady-state supported by finite element analysis (FEA) with the help of ANSYS MAXWELL and ANSYS FLUENT. Then the temperature elevation attributes within Gas Insulated Switchgear (GIS) and the impact of load current on the magnetic flux density and heat dispersion, were analysed in addition to that the effect of gas pressure and ambient temperature on the heat distribution were also observed. The results show that the load current has linear relation with heating power loss and temperature rise. The Ambient temperature and gas pressure show barely and effect on temperature rise. The results of this research work are valuable for accurately interpreting on-site infrared temperature measurements, with substantial practical applications in engineering.