Simulation Study on Fire Resistance Performance of Substation Frameworks with Fire-Retardant Coating Under Heating Curve Conditions Specified by ISO 834 Standard

To analyze the fire resistance performance of the substation framework protected by fire-retardant coating, herringbone column structure substation frameworks under heating curve conditions specified by the ISO 834 standard were simulated using ABAQUS software. Moreover, this study investigated the temperature field, stress field, and displacement characteristics of the substation structure under typical fire scene conditions. The research results indicate the following: (1) Without fire-retardant coating, the surface temperature of the bare substation framework reaches 500 °C within a short period, and a large temperature difference between the interior and exterior of the steel pipe is caused, which may induce brittle cracking within the steel. Within the 1000 s period from the start of heating, the strength of the steel structure decreases with the increase in temperature. Stress is gradually concentrated on the steel structure, and the heated part of the bare steel truss undergoes a deformation displacement of more than 0.1 m, making it susceptible to brittle fractures in the steel. The maximum deflection of the steel structures exceeds the critical value of 0.07 m. (2) With fire-retardant coating, the surface temperature of the steel can be maintained below 310 °C, and the stress in most areas of the substation framework remains below 170 Mpa. The displacement and deformation of the transformer frame are significantly reduced, and the deformation can be maintained below 0.02 m. All positions of the substation framework are in the upward expansion stage, and the deflection does not exceed 0.02 m.