Predictive Thermal Analysis of 500kV GIS Circuit Breakers via Coupled Multi-Field Simulation

Abstract

The temperature of the contacts is a crucial signal for successfully identifying thermal failures in GIS (Gas Insulated Switchgear) disconnects switches, which may cause dangerous electrical mishaps. This highlights the critical need of doing temperature field computations for GIS. In any electrical system, gas insulated switchgear (GIS) plays an essential role. The insulating gas's efficacy and the device's lifespan would be diminished if the conductor on the GIS busbar were to overheat. Subsequently, we optimize the busbar's output by adjusting its center distance, conductor thickness, and rotation angle. Gas insulated switchgear and gas insulated transmission lines are essential components of any reliable electrical system. For long-distance, high-power transmission, GILs are progressively displacing traditional overhead lines because to their lower overall cost and improved efficiency in space usage and power transfer. Studying GILs' power loss with temperature profiles is important for their dependable functioning and their design optimization ease. Variations in conductor thickness accounted for over 70% of the variation in maximum temperature as well as power loss, according to the research. Combining the aforementioned methods (A1, B5, C5) allows for a decrease in GIS thermal load and energy usage. Also, following structural adjustment, the study demonstrates that SF6 gas maintains its exceptional insulating ability. This is proven by calculating the gas breakdown margin. Finally, this work adds to our knowledge of how threephase GIS busbars conduct heat, which is useful for optimizing and designing these systems.  The skin effect of current is a major contributor to the temperature of gas insulated bus bars, which are the result of linked multiphysics fields including fluid, thermal, and eddy current. This study builds a 3D model of a GIS bus bar and uses additional fine grids to account for the skin impact of current in order to get an accurate loss value. The three-phase GIS bus bar's temperature field distribution is predicted using the finite element approach in conjunction with fluid analysis.  The study shows that multi-physics field coupling simulations are useful for enhancing the performance and reliability of power system components, particularly GILs, by looking at the temperature field of 500kV GIS circuit breakers. Doing so improves the efficiency and dependability of the power system's components. The primary finding of this study is that three-phase GIS busbars should be designed with optimal heat transfer and other factors in mind.  A 500 kV GIS disconnect switch is modeled using a multi-physics simulation in this article. To begin, the distribution of losses is determined by electromagnetic modeling calculations. The distributions of both the temperature and the flow field are then obtained by coupling the computed losses to the fluid field's temperature as heat sources. In anomalous contact situations, this is used as a basis for additional temperature field investigation for varied contact resistance values. According to the findings, the GIS disconnect switch's top contacts are where the majority of the temperature spikes occur. When there is insufficient contact, the maximum temperature is 45. 23 percent greater than when everything is running well.  For precise analysis of the temperature field of a 500kV GIS circuit breaker, multi-physics field coupling simulation is essential.