高压直流输电谐波传递特性的研究

发布时间：2018-04-30 02:21

本文选题：高压直流输电 + 谐波传递　；参考：《华北电力大学》2014年硕士论文

【摘要】：为解决我国能源分布及负荷发展极不平衡的问题,必须发展远距离、大容量的高压直流输电,实现大区域电网之间的互联。由于大功率电力电子设备的投入,谐波问题也随之产生。本文分析了高压直流输电谐波传递特性及其影响因素,在此基础上,研究由谐波传递引起的谐波不稳定问题及其解决方法。首先,本文从理论上分析谐波传递特性,采用开关函数法推导出谐波从换流器交流侧到直流侧、谐波从换流器直流侧到交流侧以及谐波在交直流系统中的传递规律。随后对谐波传递可能引起的谐波不稳定进行理论分析,理论推导得到交直流侧谐振频率互补公式以及换流器交直流侧的等值谐波阻抗。提出谐波不稳定的几种抑制措施。在PSCAD/EMTDC仿真软件中搭建接近工程实际的高压直流输电谐波传递模型。通过谐波注入法在模型中不同点注入不同次数和幅值的谐波,比较仿真结果,验证了谐波传递特性。探讨了影响谐波传递的三个因素及其影响程度,包括传输功率、运行方式和平波电抗器。针对仿真中由直流侧3次谐波传递引起的谐波不稳定问题,采用频率扫描法得到模型中交流系统和直流系统的谐波阻抗频率特性,结合理论推导分析了出现谐波不稳定的原因。通过在换流器交直流侧加装非特征谐波滤波器有效地抑制了谐波不稳定。
[Abstract]:In order to solve the problem of unbalanced energy distribution and load development in China, it is necessary to develop high voltage direct current (HVDC) transmission with long distance and large capacity, so as to realize interconnection among large regional power networks. Due to the input of high power electronic equipment, harmonic problems also arise. In this paper, the harmonic transmission characteristics of HVDC and its influencing factors are analyzed. On the basis of this, the harmonic instability caused by harmonic transmission and its solution are studied. Firstly, the harmonic transfer characteristics are analyzed theoretically, and the harmonic transfer rules from AC side to DC side of converter, from DC side to AC side of converter and in AC / DC system are deduced by switching function method. Then the harmonic instability caused by harmonic transmission is theoretically analyzed and the complementary formula of AC / DC resonant frequency and equivalent harmonic impedance of AC / DC side of converter are derived theoretically. Several measures to restrain harmonic instability are put forward. The harmonic transfer model of HVDC is built in PSCAD/EMTDC simulation software. The harmonic transfer characteristics are verified by comparing the simulation results with the harmonic injection method at different points in the model for different times and amplitudes of harmonics. Three factors affecting harmonic transmission and their influence degree are discussed, including transmission power, operation mode and wave reactor. Aiming at the harmonic instability caused by the third harmonic transmission at the DC side, the harmonic impedance frequency characteristics of the AC system and the DC system in the model are obtained by frequency scanning method, and the reasons for the harmonic instability are analyzed in combination with the theoretical derivation. The harmonic instability is effectively suppressed by adding a non-characteristic harmonic filter to the AC / DC side of the converter.
【学位授予单位】：华北电力大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM721.1

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