Simulation And Safety Performance Improvement Of Short-Circuit Arc Impact Process Of 10 KV High Voltage Switchgear

10kV switchgear is widely used in power system because of its convenient operation and reliable operation.However,due to its sealing structure,once the internal short-circuit arc fault occurs,the rapid formation of high temperature and high-pressure gas cannot be discharged in time,it will cause explosion and fire accident,seriously affecting its safe operation.At present,10kV switchgear has been configured with typical safety settings,including the setting of independent function cabins,each function cabin corresponding to the independent discharge channel,the factory needs to meet the internal combustion arc test detection.However,the explosion accidents still occur from time to time,and the safety strength intensity needs to be checked and strengthened.In this paper,the impact process caused by the short-circuit arc inside the switchgear is simulated and calculated,and the safety intensity design method of the switchgear is proposed.Aiming at the weak parts of switchgear safety protection,the improvement and optimization are carried out to improve the overall safety performance of the switchgear.Based on the coupled finite element method of temperature field,fluid field and displacement field,the short-circuit arc impact process inside the switchgear is simulated by using the method of heat source equivalence and compartment modeling,taking into account the complexity and accuracy.The reliability of the proposed calculation method is verified by experiments.Taking the cable room of KYN28-12 switchgear as an example,the action time t=10.5ms of the relief plate under the internal short circuit arc shock process is obtained by simulation calculation,and whether the maximum stress distortion point of the cabinet exceeds the limit stress value of the cabinet material is used as the basis for the safety design and verification of the cabinet.The stress distribution of the indoor wall of the switch cabinet cable at this time is simulated and calculated.Combined with the proposed safety design method,the safety design proposal of 2mm wall thickness of high-quality steel cabinet is obtained.For the rear cabinet door with weak protection in the process of internal short-circuit arc impact,the safety suggestion of installing at least 20 high-strength M10 bolts is given.Through relevant tests,the reliability of the design results is proved,which can provide theoretical basis and method guidance for the safety design of 10 kV switchgear.In order to improve the overall safety performance of switchgear,this paper puts forward the calculation method and design suggestions for improving the safety margin of switchgear from the perspective of comparing the safety margin of switchgear body and cabinet door.Taking the cable room of KYN28-12 switchgear as an example,the safety margin values of the cabinet body and the cabinet door are obtained(51%and 2%respectively),and it pointed out that the key to affecting the safety margin of the switchgear is to improve the safety margin value of the cabinet door.The method of covering ceramic silicone rubber polymer composite refractory inside the cabinet door is proposed to improve the safety margin of the cabinet door.The safety margin of the cabinet door can be increased to 70%by covering 3mm thick ceramic silicone rubber polymer composite refractory in the large pressure area inside the cabinet door of the cable room,and then the overall safety performance of the switch cabinet can be improved.Compared with the traditional improving method,it is more targeted and promotes the lightweight development of equipment,which provides new solutions and methods for the safety level improvement of 10kV switchgear.