【作者】 司秉娥；

【导师】 徐建源；

【作者基本信息】 沈阳工业大学 ， 电机与电器， 2008， 硕士

【摘要】 针对高压及特高压开关设备小型化及绝缘性能的要求,本文对40.5kV/SF₆充气式开关柜（C-GIS）中断路器气室三维电场进行了分析计算;对1100kV GIS中隔离开关气室的大型三维电场问题进行了分析计算;对1100kV GIS中盆式绝缘子的瞬态电场进行了分析计算。以便较精确的预测设备的电场分布,从而提高开关设备的绝缘水平。首先,本文对40.5kV/SF₆ C-GIS断路器气室三维电场进行了分析计算。针对产品实际结构的复杂性,应用网格划分控制工具的参数设置和疏密网格等分网方式对模型进行网格划分,同时对电场分析中结构比较复杂的区域进行子建模以放大危险区域,以提高电场计算精度。通过电场的结果分析,得出断路器气室内各区域电场强度最大的位置及电场强度的比值,进而为断路器气室的绝缘结构设计提供理论参考。其次,对1100kV GIS中隔离开关室三维电场进行了分析计算。1100kV GIS中隔离开关室尺寸较大,约是40.5kV C-GIS中断路器室实际尺寸的7倍,且电极形状复杂。对于GIS中隔离开关室的大型三维电场问题,本文利用自编程序,尝试将区域分解法与现有软件相结合对其进行三维电场分析计算。分析接地开关静触头直径与边倒角尺寸对触头表面附近的电场分布影响。运用电场能量法对电容参数进行计算,得出不同位置电容计算结果,并与测试结果进行了比较。最后,GIS中隔离开关分合母线电容电流时产生的快速暂态过电压（VFTO）,具有上升时间短及幅值高的特点,并且工作气压下绝缘子沿面在VFTO作用下比雷电波作用下要危险得多。因而,本文研究VFTO作用下的盆式绝缘子的沿面电场分布。首先对VFTO数值模拟结果进行离散的傅立叶变换,利用最小二乘法对数值模拟的结果进行拟合,获得不同频率分量占整体的比例系数。再将介电常数的非线性和不同频率分量结合在一起考虑,推导出暂态电场计算的频域数学模型。利用频域数学模型,计算VFTO作用下绝缘子的电位与电场强度分布,从而进一步分析绝缘子的绝缘性能。更多还原

【Abstract】 For the requirement of miniaturization and insulation properties of high voltage and extra high voltage switchgear, three dimensional electric field analysis model of 40.5kV/SF₆ C-GIS circuit breaker is analyzed and calculated. Three dimensional electric field of large size 1100kV GIS disconnector cabinet is analyzed and calculated. Transient electric field of 1100kV GIS insulator surface is analyzed and calculated. So electric field distribution of switchgear can be predicted more exactly, then the level of insulation can be improved.Firstly, three dimensional electric field analysis model of 40.5kV/SF₆ C-GIS circuit breaker is analyzed and calculated. For the complexity of actual product structure, the model was meshed by using the parameter settings and sparse and dense meshes of the grid dividing control tool, and the regions of complex structure are rebuilt for amplifying dangerous regions and improving the precision of electric filed calculation. According to the analysis result, the positions of maximum electric field strength each area and the intensity values are obtained. Then more theory reference can be provided for the design of insulation structure.Secondly, three dimensional electric field of 1100kV GIS disconnector cabinet is analyzed and calculated. The dimension of 1100kV disconnector cabinet in GIS is seven times larger as of the dimension of circuit breaker, and the shapes of electrodes are complex. This paper compiles program for calculating the three dimensional electric field with using region decomposition method and present software. The distributions of electric field intensity and the curves of electric field intensity distributions in different electrode surfaces are acquired. Then the positions of maximum electric field strength each area and their intensity values are obtained according to the result analysis. The effects on the electric field distribution near the surface of contact caused by change of dimensions of earthing switch static contact diameter and boundary chamfer are analyzed. The capacitance parameters are calculated by using electric field energy method, then the calculation results of capacitance in different positions of disconnector cabinet are acquired, and the calculation results of capacitance parameters are compared with the test results of capacitance parameters.Finally, VFTO is generated when disconnector divide and close bus-bar capacitance current in GIS which has the feature of short rise time and high amplitude. The insulator surface is more dangerous on the effect of VFTO under the working air pressure than on the effect of lightning surge. The insulator surface is more dangerous on the effect of VFTO under the working air pressure than on the effect of lightning surge. Therefore the distribution of electric field intensity along insulator surface caused by VFTO is analyzed in this paper. Primarily the result of numerical simulation is treated by fourier transform method, then the result of numerical simulation is fitted used least-squares procedure. The fitting curve of transient waveform which caused by VFTO is obtained, then the proportion factor of various frequency in the whole is obtained. The frequency-domain mathematic model for calculating transient electric field can be deduced and the potential distribution considering the nonlinear of dielectric constant and various frequency component. Electric field intensity distribution, electric filed intensity tangential component and normal component distribution of insulator and around it caused by VFTO can be calculated, thus the insulating property of insulator can be further analyzed.更多还原