【作者】 王洋；

【导师】 张重远； 李文平；

【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】 随着我国电力系统的快速发展和电压水平的不断提高,直流输电系统因其具有诸多优点而得到了迅速发展,特别是高压直流输电,以其大容量和远距离传输的独特优势而得到了很大发展。目前,主要特高压直流输电线路全部接入500kV电网,特高压直流直接接入接收端的1000kV特高压交流电网,可充分利用特高压电网作为受电和配电平台,减少对500kV电网的影响,可有效增强系统稳固性。在多个领域内产生重大作用,比如社会经济层面、实际工程应用领域以及技术创新方面。本文在西门子换流变制造体系角环-纸筒器身绝缘结构的基础上增加绝缘距离,增加角环纸筒数量,进行网侧1000kV,阀侧±400kV换流变压器器身绝缘结构的设计。利用三维专业电场计算软件ELECTRO和ELECNET对以下几点进行仿真分析。1、网侧1000kV换流变压器线圈波过程分析,网侧电压升至1000kV,意味着网侧雷电冲击水平的提升,同时,网侧线圈匝数也增加。因此,参照ABB制造体系线圈结构,按照试验电压的提升,网侧线圈采用多根组合扁线并绕,首端插花纠结结构型式来进行设计。而阀侧绕组扔采用经典的内屏蔽连续式结构。2、网侧1000kV换流变器身主绝缘结构分析,换流变压器的特殊工况决定了它的主绝缘既承受着交流变压器所承受的全部电场作用和试验电压下的电场作用,同时还要承受正常工作中的直流电场作用、事故状态时和逆向工作时的极性反转电压作用、以及直流试验电压下的直流电场作用。我们在西门子经典换流变设计制造体系器身绝缘结构的基础上,适当增加绝缘距离,增加角环数量,设计网侧1000kV,阀侧±400kV换流变的器身绝缘结构,并对其交直流电场进行仿真计算,包括网侧感应电场计算,阀侧交流电场计算,阀侧直流电场计算。3、1000kV网侧引线绝缘结构分析,换流变压器的网侧引线绝缘装置是一个由油和纸绝缘、金属电极和支撑部件组合的多介质、形状复杂的引线绝缘结构,需考虑引线到绕组、铁心、夹件和油箱等之间的绝缘距离,还需要重点分析计算套管均压球及绕组连接线处油隙等高场强区域引线的电场分布。4、网侧1000kV换流变阀侧引线绝缘结构分析,阀侧绕组位于铁心侧,因此只能采用端部轴向出线,由于网侧1000kV需要较大绝缘距离,在一定程度上会对阀侧绕组至铁心、夹件等内部接地结构件的绝缘距离造成压迫,造成阀侧绝缘空间紧张。本课题需设计阀侧±400kV端部轴向出线绝缘结构,对其三维电场进行详细校核及计算。并根据计算结果优化其绝缘结构,反复修改最终得到符合设计要求的引线绝缘结构。更多还原

【Abstract】 With the rapid development of China’s power system and the continuous improvement of the voltage level,the DC transmission system has been rapidly developed due to its many advantages.In particular,HVDC transmission has been achieved with its unique advantages of large-capacity and long-distance transmission.Great development.At present,the main UHVDC transmission lines are all connected to the 500kV power grid,and the UHVDC is directly connected to the 1000kV UHV AC grid at the receiving end.The UHV power grid can be fully used as a power receiving and distribution platform to reduce the impact on the 500kV power grid.Effectively enhance system stability.It has a major role in many areas,such as socio-economic aspects,practical engineering applications,and technological innovation.In this paper,the insulation distance is increased on the basis of the insulation structure of the angle ring-paper barrel body of Siemens’ commutative manufacturing system,and the number of corner ring cylinders is increased.The insulation structure design of the body side of 1000kV and±400kV converter transformer side is carried out.The following points were simulated and analyzed using the three-dimensional professional electric field calculation software ELECTRO and ELECNET.1.In terms of analysis of the coil wave process of 1000kV converter transformer on the network side,if the voltage on the grid side rises to 1000kV,it means that the level of lightning surge on the grid side will be improved and the number of turns on the grid side coil will also increase.Therefore,based on the ABB manufacturing system coil structure and in accordance with the increase of the test voltage,the net-side coil adopts a plurality of combined flat wires and is designed around the structure type of the first-end insertion correction.The valve side winding throws a classic inner shield continuous structure.2.Analysis of the main insulation structure of the 1000kV converter transformer body on the network side,the special working conditions of the converter transformer determine that its main insulation withstands all the electric field effects of the AC transformer and the electric field under the test voltage,and it also has to withstand DC electric field during the normal operation,the polarity reversal voltage at the time of accident and reverse operation,and the DC electric field under the DC test voltage.Based on the insulation structure of the Siemens classic commutation design and manufacturing system,we increase the insulation distance appropriately and increase the number of angle rings,and design the network-side 1000kV,valve-side±400kV transformer body insulation structure,and submit DC electric field simulation calculations including grid-side induced electric field calculations,valve-side AC electric field calculations,and valve-side DC electric field calculations.3,During the analysis of 1000kV net side lead insulation structure,the net side lead insulation device of the converter transformer is a multi-dielectric,complex shape lead insulation structure composed of oil and paper insulation,metal electrodes and supporting components,and it takes into consideration the lead to the winding,iron core,and the insulation distance between the clamps and the fuel tank.It also needs to calculate the electric field distribution of the high field strength region leads,such as the oil pressure gap at the casing and the voltage at the winding connection line.4,The analysis of the side lead insulation structure of the side 1000kV commutation valve is that the valve side winding is located on the side of the core,so only the axial exit of the end can be adopted.Since the side 1000kV needs a large insulation distance,the valve side winding will cause pressure to a certain extent on the insulation distance of the internal grounding structure such as iron cores and clips,thus causing the valve side insulation space to be tight.This project needs to design the axial exit wire insulation structure of the±400kV end of the valve side,and conduct a detailed check and calculation of its three-dimensional electric field.According to the calculation results,the insulation structure is optimized,and the insulation structure of the lead wire that meets the design requirements is finally modified.更多还原