| With the rapid development of economy and industry,the demand for installed capacity of power grids has gradually increased,and large-capacity,long-distance,and high-voltage power transmission technologies have also begun to enter a stage of rapid development.However,during the operation of the gas-insulated metal-enclosed transmission line(GIL),the current flowing through the high-voltage conductor will cause the device to heat up,reduce its insulation level,cause partial discharge and even lead to insulation breakdown,which will affect the reliable operation of the device.The most important thing in this research field is to clarify the temperature distribution law of the basin insulator and the electric field distribution under the temperature field.In this paper,a mathematical model of three-dimensional thermal-fluid-electric coupling numerical analysis of GIL gas chamber is established.Against the background of the actual GIL pipe corridor,the finite volume method is used to calculate the temperature field of GIL in the steady state,and the length of 2m is taken as the research object.Because the interior of the GIL pipe is axisymmetric,a reasonable simplified model is given,so only 1/2 models.Assuming that the GIL does not consider the proximity effect,the gases are all incompressible,and the GIL vortex losses are not considered.The central guide rod is the heat source,and the conductor transfers heat to the enclosure through natural convection and radiation.Since the GIL is placed in the tunnel,regardless of the effect of solar radiation,the enclosure transfers heat to the outside environment through natural convection.Based on the simulation study of the temperature field of the basin insulator and the change law of the electrical conductivity of the insulator with the temperature,a multi-physics coupling calculation analysis is conducted to coMPare the influence law of different environmental factors on the electric field of the basin insulator.The research results show that the temperature field and the airflow field distribution are analyzed with an ambient temperature of 20?,a load current of 3150 A,and an insulating gas pressure of 0.7MPa.The temperature distribution of SF6 gas on both sides of the insulator is similar to that of the insulator,and the top temperature is higher than the bottom,and the concave surface temperature and gas chamber temperature of the insulator are slightly higher than the convex surface temperature and gas chamber temperature.The temperature field of thebasin-type insulator under different insulating gas pressures is calculated when the ambient temperature is 20 ° C and the load current is 3150 A.The temperature of the insulator has a non-linear relationship with the pressure of the insulating gas.As the pressure of the insulating gas increases,the maximum temperature of the insulator gradually decreases,and the minimum temperature of the insulator hardly changes.Furthermore,the temperature field of the basin-type insulator is calculated at different load currents and at different ambient temperatures.It is concluded that the greater the load current,the higher the insulator temperature,and the ambient temperature and insulator temperature change in a linear form.Analyze the electric field calculation of the basin-type insulator at an ambient temperature of293 K,a load current of 3150 A,and an insulation gas pressure of 0.7MPa.The overall GIL electric field tends to have a high electric field strength near the center guide bar and a low electric field strength near the housing.The electric field strength distribution of the insulator shows a tendency that the convex field strength is higher than the concave field strength,and the high point of the concave field strength of the insulator appears below the central guide rod,while the concave field strength appears above the central guide rod.The electric field strength in the low temperature area near the housing is higher than the high temperature area near the guide rod. |
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