Case study on fire resistance of fire stopping system in Ultrahigh-voltage Direct current converter station

In this study, two existing fire stopping systems of the valve hall in the converter station were selected, and the heat transfer process in the key areas was simulated by the ANSYS software under the condition of a hydrocarbon temperature rise curve. The main thermal parameters, such as temperature field, thermal flux, and thermal gradient, were obtained, and the temperature rise characteristics of measuring points were tested through the Fire Test Furnace and the one-dimensional heat conduction model. The simulation results show that Model 2 exhibits superior thermal resistance performance compared to Model 1, and the maximum heat flux density occurs at the square steel (keel) position. During the fire resistance test, it is observed that the fireproof mortar at the connection of Autoclaved Lightweight Concrete board in Model 1 exhibits significant detachment and cracking, accompanied by the emission of white smoke. Compared with the temperature rise of the measuring points in Model 1 and Model 2, the heating rate of measuring points f1 and f2 is 0.0471 °C/s and 0.0159 °C/s, respectively. The temperature value obtained from the fire resistance test exceeds that calculated by the one-dimensional heat conduction model.