【作者】 周佳；

【导师】 周理兵；

【作者基本信息】 华中科技大学 ， 电气工程， 2019， 硕士

【摘要】 UHVDC(特高压直流输电)换流站用大型调相机,是一种专用于电力系统动态无功补偿的旋转电机设备,国网公司已提出采用大型调相机作为特高压直流换流站动态无功补偿设备,首批300MVA大型调相机已成功研制,目前正处于试运行与应用推广阶段,直轴电抗作为大型调相机重要性能参数,研究其影响因素,探究不同电磁结构尺寸和不同饱和运行状态下,直轴电抗的变化规律,对于大型调相机的电磁结构参数优化设计、参数精确测量,以及其在电力系统的成功应用与顺利推广,具有一定的参考价值。本文以国网第一批300Mvar大型调相机为研究对象,从有限元电抗参数计算、真机参数实验等方面,对电磁结构尺寸和铁心磁路饱和对于直轴电抗的影响,进行了计算分析与实验验证。为下一步大型调相机的电磁结构参数优化、模型样机制作、瞬态参数试验方法研究与参数辨识奠定基础。首先,本文对换流站用大型调相机的参数需求进行了分析。论述了换流站用大型调相机的典型运行工况,并分析了换流站对调相机的无功输出能力的要求,以及对应的关键性能参数要求,并对比传统汽轮发电机和普通调相机的典型参数,说明大型调相机的无功输出的能力指标要高,并且直轴电抗参数值要低很多。其次,建立了300Mvar调相机的有限元参数化物理模型,分别对基于超导回路和三相突然短路的有限元瞬态直轴电抗计算,进行了原理性推导和参数计算,得到了在设计电磁参数下瞬变电抗与超瞬变电抗的计算值。在此基础上,对电磁结构尺寸对直轴电抗的影响,进行了有限元计算与分析绘出了不同结构参数时的直轴电抗的变化曲线,根据计算结论对调相机进行了算例分析,结论可以为调相机电磁结构优化设计,提供参考。并进一步地,采用冻结磁导法,对瞬态过程中铁心饱和对直轴电抗的影响,进行了有限元计算与分析,绘出了瞬态过程中不同定转子电流下的直轴电抗的变化曲线。并对300Mvar调相机进行电抗参数实验,验证了有限元计算直轴电抗的准确性。最后,对本文内容进行了总结,以及对下一步工作计划进行了展望。更多还原

【Abstract】 UHVDC converter station high-capacity condenser is a kind of rotating motor equipment specially used for dynamic reactive power compensation of power system.State Grid Corporation has proposed to consider high-capacity condenser as dynamic reactive power compensation equipment for UHVDC converter station.The first batch of 300 MVA large-scale condenser has been successfully developed,and is currently in the stage of trial operation and application promotion.Direct axis reactances are important parameter for highcapacity condenser.It is of great significance to optimize the design of the electromagnetic structure parameters of high-capacity condenser,to measure the parameters accurately,and to successfully apply and popularize it in the power system to study the influencing factors of the important performance parameters of the condenser,and to explore the variation law of the direct axis reactances under different electromagnetic structures and different saturated operation conditions.In this paper,the first batch of 300 Mvar high-capacity condenser in China National Grid are taken as research objects.The effects of electromagnetic structure and magnetic circuit saturation on the direct axis reactances are calculated,analyzed and verified by experiments from the aspects of finite element calculation and real machine experiment.It lays a foundation for the next step of the optimization of electromagnetic structure parameters of high-capacity condenser,the manufacture of model machine,the research of transient parameter test method and parameter identification.Firstly,the parameter requirement of high-capacity condenser used in converter station is analyzed.The typical operating conditions of high-capacity condenser used in converter station are discussed,and the requirements of reactive power output capacity and corresponding key performance parameters of the converter station are analyzed.Compared with the typical parameters of traditional turbogenerator and common condenser,it shows that the reactive power output capability index of high-capacity condenser is higher,and the value of direct axis reactances parameter are much lower.Secondly,the finite element parameterized physical model of 300 Mvar high-capacity condenser is established.The finite element transient reactance calculation based on superconducting circuit and three-phase sudden short circuit is carried out respectively.In this part,the theoretical derivation and parameter calculation are carried out,and the calculated values of transient reactance and super-transient reactance under the designed electromagnetic parameters are obtained.Furthermore,the influence of the size of electromagnetic structure on the reactance of the direct axis is calculated and analyzed by finite element method,and the curves of the reactance of the direct axis with different structural parameters are drawn.According to the calculation results,an parameter adjustment example of the condenser is analyzed.The conclusion can provide reference for the optimization design of the electromagnetic structure of the condenser.Moreover,the influence of core saturation on the reactance of the direct axis in transient process is calculated and analyzed by using the frozen permeance method,and the curves of the reactance of the direct axis under different stator and rotor currents are drawn.The reactance parameters of 300 Mvar high-capacity condenser are tested,and the accuracy of the finite element method for calculating the direct axis reactance is verified.Finally,this paper summarizes the content of this paper and looks forward to the next work plan.更多还原