动车组车顶高压电器箱的电场计算及优化设计

集成化的动车组车顶高压电器箱,其箱内电气设备布局非常紧凑,可能造成某些设备的金具表面电场集中,导致电晕放电。建立动车组高压电器箱的三维有限元计算模型:在正常工况(额定工作电压)下,基于静电场分析箱内整体电场的分布规律;在异常工况(标准雷电冲击电压)下,基于瞬态电场分析箱内整体电场分布及其随时间的变化规律。针对高压电器箱内表面场强较集中的金属部件,分别进行电场调整:采用改变电极形状的方法,调整高压隔离开关的表面电场;采用包裹绝缘护套的方法,调整电压互感器汇流排的表面电场;采用增设开口均压环的方法,优化真空断路器上/下刀片的表面电场,并借助正交化实验设计方法,确定开口均压环的最佳设计参数。最后,通过悬浮金属的电位测量试验,验证有限元计算的正确性。文中的分析计算和结构优化方法可为高压电器箱的工程设计提供参考。

Electric Field Calculation and Optimization of High Voltage Apparatus Box on Car Roof of Electric Multiple Unit

Installed on the roof of the electric multiple unit,the compacted layout inside the integrated high voltage apparatus box may cause the concentrated distribution of the electric fields on the fittings of some electrical equipment and lead to corona discharge.In this paper,a three-dimensional finite-element(FE)model of the high voltage apparatus box is established.Under the normal operating voltage,the overall electric field distribution in the high voltage box is analyzed based on the electrostatic field and under the abnormal condition,e.g.standard lightning impulse voltage,the overall electric field distribution and its variation with time in the high voltage box are analyzed based on the transient electric field.For the components with high surface electric field intensity in the high voltage apparatus box,different approaches have been proposed to adjust their electric fields.The surface electric field of the high voltage disconnector is adjusted by changing the shape of electrode;that of the bus-bar connected to the voltage transformer by laying the insulation sheath;still that of the upper and lower blades of the vacuum breaker by installing open corona rings,whose optimum parameters are determined through the orthogonal test method.Finally,the accuracy of the FE calculation is validated by experiments on the potential measurement of floating fittings.The presented FE calculation and optimization methods can provide certain reference for the engineering design of the high voltage apparatus box.