Three-dimensional numerical simulation and experiment of moisture condensation mechanism inside high voltage switchgear

Abstract

High voltage switchgear is prone to moisture and condensation in environments with high humidity and large temperature difference, which seriously affects its safe and reliable operation. This paper uses three-dimensional numerical simulation, experimental verification, and mechanism analysis to examine the moisture condensation problem inside high voltage switchgear. First, a three-dimensional electromagnetic-fluid-thermal-humidity coupling field simulation model of full-size 40.5 kV switchgear is established, and the temperature distribution and humidity diffusion process are calculated. Then, a refined measurement is performed on the temporal and spatial distribution of temperature and humidity inside the switchgear to validate the simulation results. Finally, the condensation development sequence of each room and insulating component is revealed for the first time by combining the natural penetration test and simulation results. The results show that the relative errors of temperature and humidity data between the simulation and experimental results are within ±6%, which verifies the three-dimensional numerical simulation. Condensation is easy to occur on insulating components, including the current transformer and contact box in the cable room, where the humid air first accumulates. Furthermore, the condensation formation time decreases with the increase of relative humidity or temperature difference. The research results can provide reference for the anti-condensation measures for high voltage switchgear.