柔性直流输电换流阀屏蔽系统表面电场计算

发布时间：2018-11-18 16:12

【摘要】：柔性直流输电换流阀屏蔽系统的表面电场计算与屏蔽效果分析对阀塔均压环设计与表面场强控制具有重要作用,本文使用伽辽金间接边界元方法首先对理想化模型屏蔽系统的屏蔽效果进行研究,构建理想化屏蔽系统模型并分别对未加均压环的阀箱体结构与施加均压环的整体结构进行表面场强计算,具体分析了均压环的高度、位置、间距对阀箱体结构表面场强的影响,获得了一定的规律；进一步对不同的均压环设计方案进行比较,在满足约束条件下根据比较结果总结了合适方案,施加合适方案下的均压环使阀箱体得到良好屏蔽且均压环无起晕现象。比较结果说明换流阀体结构外部均压环之间距离越大,阀箱体结构所对应的棱边中点场强越大,均压环的施加使阀箱体模型对应尖角部位表面场强大幅度减小且均压环高度越大,阀箱体尖角部位表面场强越小。本文对实际工程中换流阀屏蔽系统的屏蔽效果进行详细地研究,针对工程中的绝缘要求分析改变均压环的尺寸、间距等参数后是否满足屏蔽要求；进一步在绝缘设计过程中调整屏蔽系统结构,提出了考虑阀体模块、横板立柱、法兰以及球等结构的计算模型,使计算更加准确,计算结果表明实际工程中法兰表面场强不可忽略,侧面应做成光滑曲面。根据电压施加方式,对实际阀塔结构分成不同时刻不同情况建立考虑较为全面的计算模型,详细介绍了每种情况下的建模方式、原理、电压施加方式并计算阀塔结构中关键部位的表面电场,总结了规律并验证了实际工程中屏蔽系统的绝缘可行性,解决了工程中的绝缘设计问题。
[Abstract]:The calculation of the surface electric field and the analysis of the shielding effect of the flexible HVDC converter valve shield system play an important role in the design of the valve tower pressure sharing ring and the control of the surface field intensity. In this paper, Galerkin indirect boundary element method is used to study the shielding effect of the idealized model shielding system. The idealized shielding system model is constructed and the surface field strength of the valve box structure without the uniform pressure ring and the whole structure with the uniform pressure ring applied are calculated respectively. The influence of the height, position and spacing of the uniform pressure ring on the surface field intensity of the valve box structure is analyzed in detail. A certain rule is obtained. Furthermore, the different design schemes of the equalizing ring are compared. According to the comparison results, the suitable scheme is summarized under the constraint condition. The pressure sharing ring under the suitable scheme can make the valve box get good shielding and there is no halo phenomenon in the equalizing pressure ring. The comparison results show that the greater the distance between the outer pressure rings of the commutation valve body is, the greater the field intensity of the center point corresponding to the valve box structure is. The application of the uniform pressure ring reduces the strong amplitude of the surface field of the valve box corresponding to the sharp angle and the greater the height of the uniform pressure ring, the smaller the surface field intensity of the valve box is. In this paper, the shielding effect of commutation valve shielding system in practical engineering is studied in detail. According to the insulation requirements in engineering, whether the parameters such as the size and spacing of the pressure sharing ring can meet the shielding requirements are analyzed. Furthermore, the structure of shield system is adjusted in the process of insulation design, and a calculation model considering the structure of valve body module, transverse plate column, flange and ball is put forward to make the calculation more accurate. The calculation results show that the flange surface field strength can not be ignored and the flange surface should be made into a smooth surface. According to the way of applied voltage, the calculation model of the actual valve tower structure is established and considered in different time and different situation, and the modeling method and principle of each case are introduced in detail. The voltage applied mode and the surface electric field of the key part of the valve tower structure are calculated, the regularity is summarized and the insulation feasibility of the shield system in the actual engineering is verified, and the insulation design problem in the engineering is solved.
【学位授予单位】：华北电力大学(北京)
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM721.1

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