Internal Arcing Simulation And Cabinet Strength Optimum Of 12kV Switchgear

12kV high voltage switchgear are widely used in urban power supply and distribution system, but due to the problem of design, manufacture, installation, operation and maintenance and other aspects, it has a relatively high accident rate, and there are lots of reasons leading to faults. The internal arcing fault is a frequent and a catastrophic fault, it will brought hazards to the equipment and personal safety. For the switchgear, have an internal arcing experiment and simulation analysis, completely grasp the development of the internal arcing fault is an effective way to prevent and control the internal arcing faults.In this research, the basic theory of the internal arcing in switchgear is briefly introduced, such as arc fault characteristics, mechanism and so on, which determine the significance of the internal arcing simulation calculation in the switchgear. The cabinet structure of the switchgear is analyzed comparatively, and KYN28-12 (Z) switchgear is selected as calculated cabinet type in this research. The internal arcing experiment in switchgear is carried out at the experiment station, and it passed.Secondly, internal arcing in switchgear is simulated. In the simulation process, using the GAMBIT pre-processor to establish three-dimensional computational model, and the model is solved by FLUENT software. In the solution process, the parameters are changed respectively, such as the length and depth of pressure relief cover, and the loading position of arc of the air chamber. Simulation results shows that the length and depth of air chamber affect pressure change process bigger than the arc loading position.And then, based on the simulation calculation of internal arcing in the switchgear, cabinet strength of the switchgear was checked by using the first strength theory. The results shows that the switchgear's cabinet can meet the requirements of the cabinet strength, and it can withstand the tremendous impact of internal arcing.Finally, in the simulation process local position of the door suffer impact severely, switchgear s door strength should be optimized. the shape of the switchgear's cabinet door is changed, in the arc process the doors with different shapes that suffer the impact by internal arcing are analyzed respectively, and make the impact force to the cabinet is smallest. The results before and after the optimization are comparative analyzed, the optimal conclusion. The research provides a theoretical basis for the switchgear design.