Thermal Analysis And Optimization Design Of Medium Voltage Gas Insulation Switch

Medium Voltage Gas Insulation Switch(GIS) is a switch which fully or partially uses the gas as an insulating medium medium without using air at atmosphereric pressure. As a main electric grid equipment, GIS own the advantages of compact structure, small area covered, high reliability, flexible configuration convenient installation, strong security, environment adaptable, small maintenance workload. Local overheating of GIS will cause thermal aging of insulation materials and breakdown in turn affect the overall life of GIS and even lead to accidents endangering the safety of the power grid. Therefore, Only accurately simulate the GIS internal temperature field and distribution of master hotspot location, can more effectively contribute to the GIS cooling optimization and thermal design, to ensure the safe and reliable operation. This paper mainly aims at the temperature rise test, the thermal simulation and design optimation using the thermal simulation software ICEPAK. Specific studies include the following aspects:(1) Temperature rise test. Based on the standard of the GIS temperature rise test, we measured the main loop resistance, arranged the switcher in a suitable way to get the reasonable results and finally obtained the steady state tenperature rise of each key point by thermocouple.(2) Thermal simulation of switcher and simulation correction. The basic theory of numerical heat transfer was introduced. The simulation process of modeling, meshing, solving and post-processing in thermal simulation software ICEPAK was introduced in detail. The actual model of switcher was simplified and simulated using multistage grid approach which reduces the number of grid and guarantee the calculation accuracy at the same time, and taking the multi-core parallel computing which leads to the simulation time about one week. With adding the experimental error, high frequency effect and other factors influencing the power loss to the simulation model, the final simulation results agree well with the experimental results.(3) Analysis of the proportion of the convective heat transfer in heat dissipation. In terms of qualitative analysis, we considered the case not calculating the radiation and case with the closed chamber in vacuum.The simulation of large-capacity transformer at an ambient temperature of 40 ℃ was analyzed. The influence of the fan’s inlet air flow rate, the fan’s own performance, arrangement form on one side, namely, the height of the fan, the number of high and low voltage winding heat airway and high voltage winding between low voltage winding and heat dissipation airway horizontal dimension and vertical dimension on the temperature rise were discussed in detail. Considering the housing vent position, the impact of the cooling arrangement of the airways, the radius of these factors on the fan transformer temperature, the ICEPAK’s steepest descent based optimization method was used in the optimal design process in which the transformer maximum temperature rise of the windings was used as objective function.