论文总字数：14924字

摘 要

电在社会发展中至关重要，无论是社会生产还是个人生活都离不开电。因此，高效安全经济的输电方式是当代重点研究对象。在远距离、大规模传输时，传统的交流输电存在损耗大且运行不稳定等问题，所以诸多学者对高压直流输电给予高度的关注。针对高压直流输电来说，其涵盖多个部分，其中比较主要的包括整流器、直流输电线路和逆变器等。当前被广泛应用到实际工程的是电网换相高压直流输电系统（LCC－HVDC）也就是传统高压直流输电系统，但这一系统缺点较多，如换相失败等。社会需求很大程度上促进了全控型电力电子器件的发展，所以，相关设计了电压源换流器型高压直流输电(VSC-HVDC)，它让LCC-HVDC换相失败的问题得以解决，但也有其自身的不足，如开关损耗较大、造价高等。因此，将两者相结合的输电方式可保留两者优点。

本研究对LCC与VSC混合的高压直流输电系统展开了深入的探究，同时探讨了整流侧LCC与逆变侧VSC对应的拓扑结构，并对其运行原理和采用的控制策略进行深入的分析，此外，其能够在PSCAD仿真环境内构建规范化的输电模型，并对控制策略的有效性进行标准化的检验。

关键词：LCC－HVDC;VSC－HVDC;混合高压直流输电

Abstract

Electricity is vital in the development of society, and it is inseparable from electricity in both social production and personal life. Therefore, efficient, safe and economical transmission methods are the focus of contemporary research. In the long-distance, large-scale transmission, the traditional AC transmission has problems such as large loss and unstable operation, so many scholars pay high attention to HVDC transmission. For HVDC transmission, it covers multiple parts, among which the main ones include rectifiers, DC transmission lines and inverters. Currently widely used in practical engineering is the grid commutated high-voltage direct current transmission system (LCC-HVDC) is also the traditional high-voltage direct current transmission system, but this system has many disadvantages, such as commutation failure. The social demand has greatly promoted the development of fully-controlled power electronic devices. Therefore, the voltage source converter type high-voltage direct current (VSC-HVDC) has been designed, which solves the problem of LCC-HVDC commutation failure. But it also has its own shortcomings, such as large switching losses and high cost. Therefore, the combination of the two transmission methods can retain the advantages of both.

In this study, the high-voltage direct current transmission system of LCC and VSC is explored in depth. The topological structure of the rectifier side LCC and the inverter side VSC is discussed, and the operation principle and control strategy are analyzed in depth. It can construct a standardized transmission model in the PSCAD simulation environment and standardize the effectiveness of the control strategy.

Keywords: LCC－HVDC，VSC－HVDC，HVDC Hybrid Transmission

目录

摘要 I

Abstract II

第一章 绪论 1

1.1 课题研究的背景与意义 1

1.2 国内外研究现状 1

1.3 本文研究内容 2

第二章 高压直流输电系统基本原理 3

2.1 直流系统的分类 3

2.1.1 直流单极输电 3

2.1.2 直流双极输电 3

2.1.3 直流多回线输电 5

2.1.4 多端直流输电 5

2.2 LCC-HVDC系统 6

2.2.1 LCC-HVDC工作原理 6

2.2.2 LCC-HVDC控制策略 7

2.3 VSC-HVDC系统 8

2.3.1 VSC-HVDC工作原理 8

2.3.2 VSC-HVDC控制策略 9

2.4 本章小结 10

第三章 混合高压直流输电 11

3.1 拓扑结构 11

3.2 LCC-VSC结构混合直流输电工作原理 11

3.3 LCC-VSC结构混合直流输电控制策略 12

3.3.1　整流侧LCC控制策略 12

3.3.2　逆变侧VSC控制策略 12

3.3.3　整体协调控制 13

3.4 本章小结 13

第四章　混合高压直流输电系统仿真研究 14

4.1 整流器模型 14

4.1.1 整流侧电路 14

4.1.2 整流侧控制电路 15

4.2 逆变器模型 15

4.2.1 逆变侧电路 15

4.2.2 逆变侧控制电路 15

4.3 仿真结果 18

4.4 本章小结 20

结论与展望 21

致谢 22

参考文献 23

绪论

课题研究的背景与意义

相比传统交流输电，高压直流输电具有以下优势：

（１）经济性

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