Abstract:

To address the poor applicability of existing pressure relief models to main transformer rooms in 110 kV underground substations, this study employed FLACS numerical simulation to calculate the maximum explosion relief pressure for different relief areas, and proposed an improved explosion pressure calculation formula based on the NFPA 68 model, specifically adapted for high-blockage transformer rooms. Furthermore, explosion relief experiments were conducted to test the rupture characteristics of three types of pressure relief materials: gypsum board, aluminum-magnesium-manganese alloy plate, and aerated concrete. The results indicate that the explosion relief pressure exhibits a nonlinear decrease with increasing relief area; when the relief area increases from 0 to 9 m², the relief efficiency reaches 67.41%, while further enlargement of the relief area yields significantly diminished efficiency gains. To control the maximum explosion relief pressure below 10 kPa, a minimum relief area of 3.13 m² is required, and a relief area of 5-10 m² is recommended to ensure the structural integrity of the building. Among the three partition wall materials, the 12 mm thick gypsum board exhibits the lowest rupture pressure (approximately 2.6 kPa), demonstrating the optimal pressure relief performance.

Key words: underground substation, main transformer room, pressure relief material, explosion relief area, explosion relief pressure