| As a crucial equipment in power distribution networks,high voltage switchgear directly affects the stability of power transmission and the safety of operation,which is crucial for electrical safety.The internal components of high voltage switchgear are complex and concentrated,and the slow heat dissipation of heating components during long-term operation can lead to the concentration of heat and cause aging,wear and tear,poor contact,and other issues of components,resulting in a vicious cycle of temperature rise,which seriously endangers the electrical and insulation performance of the equipment,and poses a great threat to the reliability and safety of normal operation.In order to better understand the heating law inside the switchgear,the present study establishes the electromagnetic-flow heat coupling simulation model of the switchgear with finite-element software through the mutual verification of test and simulation,and explores the temperature rise law of the key components inside the switchgear.Based on electromagnetics,heat transfer,and fluid dynamics,the heating reasons of switchgear are analyzed according to temperature-rise test data,and the basic structure and functions of key components of KYN28A-12 high voltage switchgear were discussed.Subsequently,the 3D drawing software Solid Works was used to establish the physical model of the switchgear,and the model was simplified and imported into the finite element analysis software COMSOL for simulation modeling.After grid division of the model,the grid was checked.After setting the corresponding boundary conditions,the electromagnetic and thermal coupling simulation is carried out to calculate the temperature field distribution of the equipment,and the temperature rise law of the key components in the switchgear is obtained.On the basis of the consistent comparison of temperature rise simulation and test results,the working conditions were adjusted to explore the influence of different environmental temperature,load current,contact resistance and other factors on the temperature rise of key components in the switchgear,and several effective temperature rise improvement measures were analyzed,such as thermal conducting polymer materials,memory alloy pressing,plum contact silver plating and so on.Conforming to fluid dynamics equations for describing thermal convection,the thermal field of a high-voltage switchgear under forced convection conditions is simulated.Firstly,the influence of flow velocity on the temperature distribution and temperature rise inside the switchgear is analyzed.With an increase in fan velocity,the temperature rise of the internal equipment in the switchgear is significantly improved compared to natural convection,and different components inside the switchgear experience varying degrees of temperature reduction.Subsequently,under these conditions,the structure of the switchgear is optimized.Baffles are added in the cable compartment to optimize the fluid field,allowing more airflow to enter the busbar compartment and improve the temperature rise inside.The ventilation hole area of the partition below the busbar compartment and the circuit breaker compartment is increased to optimize the flow field distribution in the two compartments,resulting in significant temperature reduction in the overall system and key components.Ventilation holes are added to the front partition of the busbar compartment to redirect some of the gas flow from circuit breaker compartment to the busbar compartment,homogenizing the air pressure distribution and significantly alleviating the overall temperature rise of the equipment.Finally,the study explores cooling measures by ameliorating the heat source and heat dissipation methods,such as using new materials or modifying the busbar arrangement structure. |
PDF Full Text Request