【作者】 王永茂；

【导师】 梁贵书；

【作者基本信息】 华北电力大学 ， 工程硕士（专业学位）， 2018， 硕士

【摘要】 随着我国电网络迅速发展,气体绝缘变电站(GIS)因其具有可靠性高、体积小、维护周期长、运行稳定等优点在电力系统得到了广泛的应用。GIS站中的隔离开关的开合闸,触头会发生多次击穿和重燃,并在GIS中发生多次折射和反射,最终形成特快速暂态过电压(VFTO)。VFTO对绕组类设备的危害比较大,当VFTO侵入到变压器中,有可能引起绝缘损坏、老化,甚至击穿。变压器作为电力系统中的重要设备,其能否正常运行关系到电力系统的稳定。因此研究变压器绕组VFTO分布具有重要意义。本文以此为背景,开发了大型电力变压器VFTO分布计算软件。首先介绍了VFTO产生的机理、抑制措施、对变压器产生的危害以及引起的变压器事故,本课题国内外的研究现状进行了简要概述。其次,建立变压器绕组的多导体传输线模型,并用有限元法计算电容参数,采用公式法计算电感、电阻和电导参数。接下来,采用时域有限元计算变压器绕组中过电压分布,分析了连续式、插花纠结式、普通纠结式、跨二段内屏蔽式、跨四段内屏蔽式和螺旋式等的结构特点,并为了计算方便对其线匝重新编号,得出了各种类型绕组的边界条件。分析了油道尺寸和匝绝缘厚度对最大油道梯度和最大匝间电压的影响,为绝缘设计提供理论参考。最后,在MATLAB中开发大型电力变压器VFTO分布计算软件,该软件可以计算连续式、插花纠结式、普通纠结式、四段纠结式、跨四段内屏蔽式、跨二段内屏蔽式、螺旋式等绕组中VFTO分布,能够很好的满足工程实际应用。对实际大型变压器进行了仿真计算。更多还原

【Abstract】 With the rapid development of China’s power grid,gas-insulated substations(GIS)have been widely used in power systems because of their advantages of high reliability,small size,long maintenance period and stable operation.GIS stations in the opening and closing of the switch,the contacts will be repeated breakdown and reignition occurred in the GIS multiple refraction and reflection,the final formation of very-fast transient overvoltage(VFTO).VFTO winding equipment is more harmful,when the VFTO into the transformer,may cause insulation damage,aging,or even breakdown.Transformer as an important power system equipment,its normal operation of the power system related to the stability.Therefore,the study of transformer winding VFTO distribution is of great significance.Based on this background,this paper developed the VFTO distribution calculation software for large-scale power transformers.First of all,the mechanism of VFTO generation,the suppression measures,the damage to transformers and the transformers caused by transformers are introduced.The research status of this subject at home and abroad are briefly summarized.Secondly,the multi-conductor transmission line model of transformer winding is established,and the capacitance parameters are calculated by finite element method.The inductance,resistance and conductance parameters are calculated by the formula method.Next,the finite element method is used to calculate the overvoltage distribution in the transformer windings.The structural characteristics of continuous,interweaved and entangled,common tangled,cross-section inner shielded,cross-section inner shielded and spiral are analyzed.And in order to facilitate the calculation of its turns on the renumbering,obtained the various types of winding boundary conditions.The influence of oil channel size and turn insulation thickness on the maximum oil gradient and the maximum inter-turn voltage is analyzed,providing a theoretical reference for the insulation design.Finally,the development of large-scale power transformer VFTO distribution calculation software in MATLAB,the software can calculate the continuous,flower arrangement tangled,ordinary entangled,four tangled,four-span inner shielded,span two inner shielded,spiral VFTO distribution in other winding,can well meet the practical application of the project.The actual large-scale transformers were calculated.更多还原