800kV等级高压隔离开关的交、直流电场仿真计算

Simulation of AC and DC Electric Field for 800 kV Grade High Voltage Disconnector

隔离开关的电场计算对于校核和优化开关结构,控制隔离开关的电晕损耗、可听噪声及无线电干扰水平低于限值具有重要的工程价值。因此利用分布式并行ANSYS计算平台,仿真得到交、直流电场条件下隔离开关所在空间的电场分布,并确定出最大场强及其位置。其中,交流场计算基于静电场理论,而直流场计算首先采用恒定传导电流场理论计算开关表面的电位分布。为了解决不同材料电阻率参数相差大于10个数量级时,直接采用有限元方法求解会产生的数值发散问题,根据隔离开关的结构特点,提出通过计算支柱绝缘子电阻而得到各绝缘子金属连接支架的悬浮电位,从而求得随距离呈线性分布的绝缘子表面电位。其次,根据开关表面电位分布,采用ANSYS中的Submodeling技术对空气域内的静电场分布进行求解,实现了电流场与静电场的耦合。直流场计算结果表明,开关本体与空气域交界面处电位分布连续,从而证明了该计算方法的正确性。交、直流场计算结果的汇总与对比,对于隔离开关的设计具有重要的指导意义。

The electric field calculation is important to the structure optimization of the disconnecting switch,the control of the corona loss,the audible noise,and the radio interference level.Consequently,the ANSYS software was used to calculate the AC and DC electric field distribution and to determine the value and the position of the maximum electric field.On the basis of static electric field theory,in the DC field calculation,the steady conduction current field theory was used to calculate the potential distribution on the surface of the disconnector.When the resistivity ratio between different materials was beyond 10 orders of magnitude,the problem of divergent values solved by ordinary finite element method would occur.Therefore,it was proposed that,according to the structure feature of the disconnector,the floating potential of the metal connectors was obtained by calculating the resistances of the supporting insulators firstly.Then the surface potential of the insulators was derived,which was in linear relation with the surface distance.Secondly,with the surface potential distribution of the disconnector,the ANSYS sub-modeling technique was adopted to calculate the electrostatic field distribution in the air domain.Hence,the coupling between conduction current field and static electric field was achieved.Finally,the AC and the DC field results were summarized and compared.The DC field simulation results show that the potential distribution at the interface between disconnector and air domain is continuous,which verifies proposed method.