10 kV高压开关柜内部短路电弧冲击过程仿真及安全设计

Simulation and Safety Design of Internal Short-circuit Arc Impact Process of 10 kV High Voltage Switchgear

目前10 kV开关柜由于内部短路电弧引起的爆炸事故仍时有发生,其内部短路电弧冲击过程的仿真计算方法复杂度和准确度难以兼顾,安全设计缺少理论和方法指导。该文基于温度场、流体场和位移场耦合的有限元计算方法,利用热源等效和分舱建模方式,对开关柜内部电弧冲击过程进行仿真计算,兼顾了准确性和灵活性。以电缆室为例,通过仿真计算得到内部短路电弧爆炸波能冲击下泄压板的动作时刻t=10.5 ms,以该时刻下柜体最大应力畸变点是否超过柜体材料的极限应力值作为柜体安全设计和校核依据。对该时刻下电缆室内壁应力分布进行仿真计算,结合提出的安全设计方法,得到优质钢板柜体壁厚2 mm的安全设计建议;针对内部短路电弧冲击过程中防护较为薄弱的后柜门,给出至少需要安装20个高强度M10螺栓的安全建议。通过相关测试结果,证明了该文设计方法的可靠性,可为10 kV开关柜的安全设计提供理论基础和方法指导。

At present,explosion accidents caused by internal short-circuit arc occasionally occur in 10 kV switchgears.It is difficult to compromise the complexity and accuracy of the simulation calculation method for the impact process of internal short-circuit arc,and the theoretical and methodological guidance for safety design is rarely available.Consequently,based on the finite element calculation method of temperature field,fluid field and displacement field coupling,the simulation calculation of arc impact process in switch cabinet was carried out by using the heat source equivalent method and compartment modeling method,in which the accuracy and flexibility were compromised.After taking the cable room as an example,the action time of the pressure relief panel(t=10.5 ms)under the impact of internal short-circuit arc explosion wave energy was obtained through simulation calculation thus whether the maximum stress distortion point of the cabinet exceeded the limit stress value of the cabinet material of this time was taken as the basis of cabinet safety design and calibration.The stress distribution of cable interior wall at this time was simulated and calculated.Combined with the proposed safety design method,the safety design proposal of high-quality steel plate cabinet with the wall thickness of 2 mm was obtained.Moreover,for the rear cabinet door with weak protection during internal short-circuit arc impact,the safety suggestion that at least 20 high-strength M10 bolts should be installed was given.Through the relevant test results,the reliability of the design method is proved,which can provide theoretical basis and method guidance for the safety design of 10 kV switchgear.