混合双馈入直流输电系统协调控制策略研究

论文总字数：20195字

摘 要

含有 LCC 和 VSC 的混合多馈入直流输电系统一直都是电力系统中重点关注的问题，目前在我国电力系统中，随着 LCC-HVDC和VSC-HVDC工程的不断发展，两者之间的相互作用成为许多学者不断研究的内容。在通常情况下，我们称电网换相换流器高压直流输电为LCC-HVDC，在LCC-HVDC工程中，可以从短路比(SCR)、最大传输有功功率(MAP)和有效短路比(ESCR)几个方面研究系统的稳定运行；将电压源换流器高压直流输电称为VSC-HVDC ，在VSC-HVDC工程中，可以从系统级、站级和阀级三个层次的控制方法来具体分析研究该系统。在查阅大量文献后发现，研究混合双馈入系统的基本运行机理和基本运行特性，对发现其运行规律有着至关重要的作用。所以本文将围绕绕LCC-HVDC和VSC-HVDC系统的基本原理深入分析，之后研究两个系统的相互作用，根据其稳定特性提出相应适合的控制策略，并建立仿真模型，最后依据仿真图形进行稳定性分析。

（1）混合双馈入直流输电系统的数学模型和控制策略

在查阅大量文献中可以看出，我们可以从两大部分具体展开研究，第一部分从LCC-HVDC系统的短路比(SCR)、最大传输有功功率(MAP)和有效短路比(ESCR)等几个方面综合分析了该系统的稳态和暂态运行特性，第二部分研究VSC-HVDC系统的三个层次典型控制方法有系统级、站级和阀级，其中还推导了各层次控制器的数学模型，包括交流系统的输电模型、d-q解耦控制模型等。

1. 受端系统为有源网络时混合双馈入直流输电系统的研究

首先建立了由两条LCC-HVDC与一条VSC-HVDC并联组成的混合双馈入直流输电系统并且受端系统为有源网络的模型,然后提出了两者的协调控制策略,并在PSCAD/EMTDC环境下进行仿真，根据仿真图形分析了稳态运行特性。结果表明：在VSC-HVDC子系统的作用下,增加了 LCC-HVDC子系统的最大传输有功功率MAP值,改善了该系统运行稳定性,并在一定程度上降低了暂态过电压,从而改善其故障恢复特性。因此可以得出混合双馈入直流输电系统中的VSC-HVDC子系统对交流母线电压有很强的调节能力。

关键字：混合双馈入直流输电系统;并联混合;协调控制

Abstract

Contain a mixture of LCC and VSC feed into the dc transmission system has been more focus on the problems current transmission (HVDC) and voltage source converter (VSC-HVDC) high-voltage direct current transmission technology development, so for more than mixed feed into the dc transmission system LCC-HVDC and the interaction between VSC-HVDC has a very important research significance.As the foundation of HVDC system, the basic characteristics and operation rules of HVDC system have important reference significance for the research of HVDC system.

For the research of hybrid multiple infeed system, the basic characteristics and operation rules of the system have important reference significance. And mixed double feed into the dc transmission system as the basis of mixed feed in dc system, the thesis will study mixed double feed into the dc transmission system LCC-HVDC and the coordination between the VSC-HVDC control strategy, and from the LCC-HVDC and VSC-HVDC system structure and basic operation mechanism, short circuit than SCR (effective short-circuit ratio ESCR) several aspects, such as research, to make it can make up for the inadequacy of LCC-HVDC technology, and can give full play to the LCC-HVDC and the advantage of VSC-HVDC.

1. mathematical model and control strategy of hybrid double-dc transmission system

Firstly, the mathematical model and control strategy of LCC-HVDC system and VSC-HVDC system are studied respectively, so as to specifically study the operation mechanism of hybrid double-infeed dc system. LCC-HVDC system, for example, from the two most detailed study, the first part from the short circuit ratio (SCR), maximum transmission active power (MAP) and effective short circuit ratio (ESCR) comprehensive analysis of several aspects, such as the LCC-HVDC steady state and transient operation characteristics of HVDC system, the second part study the three levels of VSC-HVDC system typical control methods systematically, ZhanJi and valve.For VSC-HVDC system, the typical control methods of VSC-HVDC at three levels of system level, station level and valve level controller are introduced, and the mathematical models of controllers at all levels are derived, including power transmission model of VSC and ac system, d-q decoupling control model and so on.

(2) research on hybrid doubly-fed HVDC transmission system when the receiver system is active network

Firstly, a hybrid double-infeed dc transmission system consisting of two LCC-HVDC and one VSC-HVDC in parallel and the receiver system being an active network is established. The simulation is carried out in the PSCAD/EMTDC environment, and the coordination and control effects of the two systems are analyzed according to the simulation graphics.The results show that under the action of the VSC-HVDC subsystem, the maximum transmitted active power MAP value of the LCC-HVDC subsystem is increased, the operational stability of the system is improved, and the transient over-voltage is reduced to a certain extent, so as to improve its fault recovery characteristics. Therefore, it can be concluded that the VSC-HVDC subsystem in the hybrid doubly-fed dc transmission system has a strong ability to adjust the ac bus voltage.

Keywords: Hybrid doubly-fed dc transmission system; Parallel mixing; Coordinated control

目 录

摘 要................................................................................................................................................. I

Abstract.............................................................................................................................................II

第1章 绪论 1

1.1 选题背景及意义 1

1.1.1 LCC-HVDC的优势与不足 1

1.1.2 VSC-HVDC的优势与不足 2

1.1.3课题的提出 2

1.2 国内外研究动态 2

1.3 论文的研究内容 3

第2章 并联混合双馈入直流输电系统的控制策略 4

2.1 LCC-HVDC的运行原理与控制策略 4

2.1.1基本运行原理 4

2.1.2 LCC-HVDC 的控制策略 5

2.1.3 LCC-HVDC 的交流系统强度 7

2.2 VSC-HVDC的运行原理与控制策略 7

2.2.1 VSC-HVDC 的运行原理 7

2.2.2 VSC-HVDC 的控制策略 9

2.2.3 VSC-HVDC 的交流系统强度 12

2.3 并联混合双馈入直流输电系统控制策略与稳态运行 12

2.3.1 基本系统结构 12

2.3.2 控制策略 13

2.4 本章小结 13

第3章 受端系统为有源网络时混合双馈入直流输电系统的研究 14

3.1混合双馈入直流输电系统供电有源网络的模型和控制策略 14

3.1.1混合双馈入直流输电系统供电有源网络的模型 14

3.1.2 混合双馈入直流输电系统供电有源网络的控制策略 14

3.2混合双馈入直流输电系统供电有源网络的分析 16

3.2.1系统参数 16

3.2.2稳态特性的仿真研究 16

3.3 本章小结 21

第4章 结论与展望 22

4.1结论 22

4.2展望 23

参考文献 24

致 谢 26

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