交流侧故障导致多落点直流输电系统换相失败研究

论文总字数：23227字

摘 要

电力输送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，由于多馈入直流输电系统能实现长距离大容量电力输送，且在运行过程中容易调节，因此已经成为我国主要采用的一种电力输送方式。不过这种电力输送系统，其直流换流站由于可能会产生相互干扰，导致换相站无法正常换相，进而导致系统送电出现故障。如果一个或多个分布式控制系统的换相失败没有得到有效控制，就会出现连续换相失败。此时将导致直流输电系统的输电功率下降，并且会引起整个电网振荡，导致其无法处于稳定运行状态。因此研究直流输电系统换相故障产生原因，并研究其抑制策略对电路系统稳定运行非常重要。

因此，本文首先对换相失败的原理进行了深入研究，对换相失败的影响因素进行了彻底的分析。同时对多落点直流输电系统逆变侧交流系统进行了单相接地短路和三相短路故障仿真分析。在仿真分析结果基础上，本文最后提出一种电流限制抑制电路换相故障的方法。该方法是通过在电路中产生虚拟电阻，从而对电路电流进行限制，实现对电路控制的效果。该抑制策略充分考虑了系统故障时可能带来的电压和电流冲击，同时也考虑了电路恢复过程中的电压波动。该控制策略可以提前对电路电流进行限制，从而避免电流中出现过载电流，其能有效抑制电路出现换相故障。

关键词：多馈入直流输电系统；换相失败；单相接地短路；三相短路；虚拟电阻

Abstract

Power transmission has always been the focus of attention in the power system. At present, in China's power system, because the multi-feed dc transmission system can realize long-distance and large-capacity power transmission, and it is easy to adjust in the process of operation, it has become the main method of power transmission in China. However, in this kind of power transmission system, the dc converter station may interfere with each other, so that the phase changing station cannot be changed normally, and thus the power transmission system fails. Continuous phase change failures occur when one or more distributed control systems fail to be controlled effectively. At this point, the transmission power of the HVDC transmission system will decrease, and the entire power grid will oscillate, leading to its failure to operate stably. Therefore, it is very important to study the causes of HVDC system commutation fault and its suppression strategy for the stable operation of the circuit system.

Therefore, in this paper, first of all, the principle of the failure of the phase change is studied in depth, and the factors affecting the failure of the phase change are thoroughly analyzed. At the same time, the single-phase grounding short circuit and three-phase short circuit fault simulation analysis are carried out for the inverter side ac system of multi-drop dc transmission system. Based on the simulation results, a method of current limiting and suppressing circuit phase change fault is proposed. In this method, virtual resistance is generated in the circuit to limit the circuit current and achieve the effect of circuit control. The suppression strategy takes full account of the voltage and current shocks that may occur when the system fails, as well as the voltage fluctuations during the circuit recovery process. This control strategy can limit the circuit current in advance, so as to avoid the overload current in the current, and it can effectively restrain the circuit from the occurrence of commutation fault.

Keywords: Multi-infeed HVDC; Commutation Failure; Single-phase Grounding Short Circuit; Three-phase Short Circuit; Virtual Resistance

目 录

摘 要 I

Abstract II

第一章 绪 论 1

1.1 课题研究的背景和意义 1

1.2 研究现状 1

1.3 论文研究主要内容 2

第二章 直流系统换相失败分析 3

2.1 换相失败原理分析 3

2.2换相失败的特点和危害 3

2.3 换相失败的主要原因 4

2.4换流阀换相失败特性研究 5

2.5 本章小结 9

第三章 交流系统故障对换相失败的影响及多馈入直流系统换相失败相互影响研究 10

3.1 交流系统故障对换相失败的影响 10

3.2 换相故障电流故障分量的计算 11

3.3 各站换相失败相互影响计算 12

3.4本章小结 15

第四章 多落点直流输电系统交流侧故障仿真分析及抑制措施 16

4.1 多落点直流输电系统仿真模型 16

4.2 换相失败抑制措施 20

4.3 本章小结 23

第五章 结论与展望 24

5.1全文总结 24

5.2 工作展望 24

参考文献 26

致 谢 28

1. 绪 论

1.1 课题研究的背景和意义

我国是一个能源匮乏并且资源分布不均的一个国家，水电资源主要分布在西南和西藏。煤矿资源主要集中在伊犁，山西，陕西和新疆宁夏。中国的电力负荷中心主要集中在中部，东部沿海地区和南部地区（广西，广东）。电力生产和消费处于相反的分布。因此，中国需要建设一批大容量，长距离输电线路，实现“西电东送”电能传输，实现优化全国资源配置和能源供应的目标。

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