Ventilation Optimization for Reduction of Indoor Air Temperature of Main Transformer Room in Urban Indoor Substation by the Variational Method

Urban indoor substations are widely used for electrical power distribution in urban networks. However, they have the problems of heat dissipation and ventilation in main transformer room, which not only influence the thermal behavior of main transformer, but also decrease the lifetime, reliability, and precision of other electronic equipment. In this contribution, we developed a new ventilation optimization method based on the variational method to solve the aforementioned problems. First, we applied the minimum average temperature of indoor air as the optimization objective combined with some constrains to establish a Lagrange function, and employed the variational method to deduce some optimized governing equations that the optimum indoor patterns should meet the minimum indoor air average temperature. Finally, a typical main transformer room model was taken as an example to demonstrate the applications of the newly developed ventilation optimization method. It was concluded that the inflowing fresh air needed to sweep more area of heating walls to take away more heat, and reduce the average temperature of indoor air. Furthermore, based on the optimized air velocity distribution, we redesigned the ventilation arrangements and reduced the indoor average temperature prominently (from 337.44 K to 314.82 K), which can provide the guidance to design the ventilation of main transformer room to improve the reliability of electronic equipment in main transformer room.