【作者】 贺达江；

【导师】 罗隆福；

【作者基本信息】 湖南大学 ， 电气工程， 2009， 博士

【摘要】 本论文主要针对四相输变电系统关键技术及装备“阻抗匹配三相变四相平衡变压器”的理论与设计开展系统性研究工作,并探索该变压器应用于四相输变电、牵引供电系统及四相整流等领域的技术特性,具有重要的理论意义和工程实用价值。我国能源、资源中心与负荷中心具有一定的不和谐性,西电东送成为必然,全国西电东送规模2020年预计达到1.4亿千瓦。四相交流输电较三相交流输电在提高输送功率密度,节省线路走廊,降低电磁污染等方面具有明显的经济技术优势。加强四相交流输变电关键技术理论研究及产品设计,在条件成熟时积极推进四相交流输电的工程化,对于提高我国电网稳定、经济运行及理论创新具有重要意义。按照《铁路中长期发展规划》要求,至2020年,我国将新建和改造电气化铁路约3万公里,研究开发阻抗匹配三相变四相平衡变压器对于提高牵引供电能力,保证牵引供电系统稳定平衡运行等方面具有十分重要的意义。论文首先研究了平衡变压器的基本原理,系统性地分析并比较了Scott-Teaser变压器、Le Blanc变压器、Wood Bridge变压器、三相变两相阻抗匹配平衡变压器、Y N/平衡变压器、四相四柱式变压器等平衡变压器的接线特点及运行特性,形成了较为完整的平衡变压器的理论构架,为新型阻抗匹配三相变四相平衡变压器的研究提供理论依据。论文提出了阻抗匹配三相变四相平衡变压器的理论构想及其接线方案,讨论了阻抗匹配平衡变压器三相侧与四相侧绕组结构关系、阻抗匹配关系、安匝平衡关系、功率平衡关系,以及三相侧与四相侧电流、电压的平衡转换关系等,着重就绕组间等值阻抗关系的确定进行了理论论证与推导,系统性地阐述了该变压器的技术特性。论文建立了阻抗匹配三相变四相平衡变压器的数学模型,运用数学模型对该新型平衡变压器在平衡状态及不对称运行状态下的性能特性进行了分析研究;建立了该变压器在相坐标下的节点导纳矩阵,为三相交流系统与四相交流系统的统一建模及相互影响分析提供理论基础,形成了阻抗匹配三相变四相平衡变压器较为完整的理论研究体系。论文根据阻抗匹配平衡变压器应满足的基本技术条件,推导了以绕组间短路阻抗值为变量的阻抗匹配三相变四相平衡变压器内部阻抗的三个约束关系,构建了由短路阻抗值表示的四相侧等值电路,以绕组间短路阻抗值为变量建立的阻抗匹配三相变四相平衡变压器约束关系是该新型变压器结构设计与制造、电气分析与计算的理论依据。论文根据所建立的阻抗匹配三相变四相平衡变压器基本理论及阻抗约束关系,完成了100kVA实验样机的参数计算与结构设计。本变压器设计的关键是实现绕组间阻抗匹配关系,基于此,通过调整绕组结构布置,利用有限元仿真模型进一步优化设计,实现了满足阻抗约束关系的实验样机的参数设计。该变压器样机的设计方案对于阻抗匹配三相变四相平衡变压器工程化设计与制造具有重要的指导意义。根据该变压器设计参数,建立了相应的阻抗匹配三相变四相平衡变压器的matlab仿真模型,该仿真模型的建立为该变压器运行性能的进一步深入研究与理论分析提供了有利条件。论文根据该变压器数学模型以及四相侧等值电路模型,进行了变压器在短路故障状态下短路电流的分析与计算,并利用上述Matlab仿真模型进行了仿真验证。故障分析结果正确,为该新型阻抗匹配三相变四相平衡变压器故障保护方案的设计提供了理论依据。本文就阻抗匹配三相变四相平衡变压器在四相输电、城市轨道交通、四相整流等领域的应用特性与应用前景进行了前瞻性研究。讨论了该新型变压器应用于四相输电系统时,三相系统与四相系统的兼容性,分析了该变压器接线方案的技术性能。提出了该变压器应用于电气化铁道AT供电系统的接线方案,并分析了其技术性能,对该变压器应用于AT供电系统的有关参数进行了设计并开展了仿真计算,表明该接线方案可实现三相系统中性点接地运行,在抑制负序电流,降低成本等方面具有明显优势。首次提出了四相整流概念,给出了该新型变压器应用于四相整流的接线方案,分析了四相整流的工作机理及相关的技术特点,为电力电子整流技术的发展及其谐波治理拓宽了一种新的途径与方法;分析并计算了四相整流电路输出电压、电流及功率因数与触发延迟角的关系;建立了四相整流电路的仿真模型并进行了相应的仿真分析,仿真结果与理论分析、计算结果相一致,表明了四相整流理论分析的正确性;对四相整流系统的谐波进行了分析,理论分析及仿真结果表明四相整流电路中直流侧只存在4的倍数次谐波,降低了整流系统低次谐波污染;在相同输出电压情况下,四相整流较三相整流因各有关电气设备的绝缘及运行维护成本大为降低,具有较低的热损耗和较为稳定的功率因素等多方面的特点,在理论及工程应用上有进一步研究的价值。更多还原

【Abstract】 This thesis concerns on the key technologies of four-phase power transmission and transformation along with’a new three-phase to four-phase impedance matching balance transformer’. The application characteristics of the novel transformer in the fields of four-phase power transmission and transformation, also four-phase rectification and traction power supply have been explored. The research is significant in theory, which has wide application prospect.In China, the main power supply region is far apart from the main load region, it is unavoidable that divert the electricity from the western region to the east . It is expected that the capacity of diversion the electricity from the western region to the east will up to 140000MW till 2020. Compared with three-phase transmission, the four-phase transmission can greatly increase the density of electricity transmission and decrease the transmission corridor cost. Also it can reduce the electromagnetic pollution of the transmission line. It has important significance for our stability of country’s power grid to pay more attentions to the four-phase transmission, and put it into practice in proper occasion.According to‘long-term develop layout of railway’, China will build or upgrade electrical-railway about 30000km till 2020. Develop the new three-phase to four-phase impedance match balance transformer is very important to the stability of the traction power supply.This thesis studied principle of the balance transformer, then compared the wiring and operation characteristics of Scott-Teaser transformer, Le Blanc transformer, Wood Bridge transformer, three-phase to two-phase impedance match balance transformer, four-phase four-core transformers and Y N/ balance transformer. The study has formed a whole theory system of balance transformer, which is the reference of the novel balance transformer research.The theory and wiring topology of a novel three-phase to four-phase impedance match balance transformer has been put forwards. The various relations of three-phase side and four-phase side have been analyzed, such as impedance match relation, ampere-turn balance relation, power balance relation and the conversion relation of current and voltage. The author concerns more on the deduction of the identification of equivalent impedance between the windings.The mathematic model of the novel three-phase to four-phase impedance match balance transformer has been established, and the characteristic of transformer in both balance status and asymmetry status have been analyzed according to the established model. Also the bus admittance matrix of the transformer in phase coordinate has been determined, which formed a foundation of the theory of three-phase to four-phase impedance match balance transformer.This thesis deduced three constraint relations in interior winding of the novel transformer, whose variable are short-circuit impedance between windings. And then the equivalent circuit of four-phase side has been settled as the theory and calculating foundation.Based on the principle of three-phase to four-phase impedance match balance transformer and the constraint relation of impedance, the parameter design and calculation of 100kVA model machine has been done. The critical technology of the design is how to realize the constraint relation of impedance by the structure layout of the windings, and apply the Finite Element Optimization Method to verify the correctness of the design. Base on the design parameters, the simulink model of the novel transformer have been established.The short-circuit currents in short fault status have been calculated, according to the established transformer mathematic model and verified the results by the simulink model, which is a basic reference of the novel transformer fault protection. This thesis has studied the application characteristic of the novel transformer in the field of four-phase transmission, urban light railway and four-phase rectifying. The compatibility of the novel transformer in three-phase transmission system has been discussed.The wiring layout of the novel transformer that apply to the electrical-railway AT power supply system has been proposed. The simulation of the application of novel transformer in AT power system has been performed, which demonstrated great advantages in negative sequence current suppression and cost reduction.This thesis proposed the concept of four-phase rectifying for the first time. The wiring layout of the novel transformer applying to four-phase rectifying has been presented, which extended a new access of harmonic suppression; The relations of output voltage, current and power factor with the trigger angle have been deduced; The simulation model of four-phase rectifying has been established, and the simulation results are consistent with theory calculation results, which verified the correctness of the theory analyses. Meanwhile, the harmonic of four-phase rectifying system has been calculated, and both theory and simulation revealed that the DC side of the four-phase rectification circuit exist harmonic only in multiples of four, which raised the lowest order of system harmonic. Given the same output voltage, the cost of insulation equipment and maintenance in four-phase rectifying largely reduced compared with three-phase rectifying. The lower thermal losses and better power stability are the merits of four-phase rectifying, and it is definitely worth to be further studied.更多还原