Purpose/Aim
Cable tunnel fire is a major cause of accidents in substations. In order to improve fireproof performance in cable tunnels of substations, numerical simulations of the fireproof performance of the cable tunnels were performed using a fire dynamics simulator by changing the arrangement of the high-voltage cables in cable tunnels.
Experimental/Modeling methods
Numerical modeling of substation cable tunnels in pyrosim simulation software. The cable tunnel is arranged with four 110kV power cables and two sets of control cables, and the fire source is set directly below the middle cable of the model. Set up a set of detectors every 0.5m directly above the fire source to monitor the temperature, CO and CO₂ concentrations with a simulation time of 3600s. According to the standard provisions in Standard for Design of Cables of Electric Power Engineering (GB 50217-2018), different layouts are set for high-voltage cables to explore the fire performance of different layouts of high-voltage cables.
Results/discussion
The study theory is consistent with the existing theory and the simulation results are differ to some extent from the existing results. According to the simulation data, the optimized arrangement of high-voltage cables in substation cable tunnels is studied, and the optimal cable arrangement method for substation cable tunnels is provided.
Conclusions
The simulation results show that the temperature, CO and CO₂ concentrations, and fire heat release rate follow the same trend for each monitoring point under different layouts of high voltage cables in cable tunnels of substations. The heat release rate of cable fires is minimized when high-voltage cables are arranged in "one" and "triangle" types, with the interlayer distance being 0.65m and 1.15m respectively. Moreover, the preferred layout type may be the "triangle" type arrangement when laying cables in cable tunnels of substations. The paper provide an optimized arrangement method of cable in cable tunnels of substations.

cable tunnel, cable fire, heat release rate, numerical simulation