田创新

[摘    要]文章对特高压直流换流站产生谐情况作了简要的介绍，然后介绍了进行谐波分析的方法选择。经过综合比较，选定开关函数法作为谐波分析的主要方法。根据开关函数的定义和变流设备具有离散采样及调制的开关特性，其输入电流波形和输出电压波形可以用许多开关函数与正弦函数的调制波形来表示，这种调制波形经过三角变换之后即可以得到谐波特性。对三相六脉动变流装置电压与电流的开关函数的过程进行了详尽的推导，并且归纳出开关函数适用于换相和非换相情况下，对称和故障时的开关函数表达式，建立电压与电流的开关函数模型，进行了算例分析。

[关键词]谐波分析;换流站;开关函数法;故障分析

[中图分类号]TM711 [文献标志码]A [文章编号]2095–6487（2021）05–00–02

Harmonic Analysis of HVDC System Based on Switching Function Method

Tian Chuang-xin

[Abstract]A brief introduction is made to the harmonic generation of UHV DC converter stations， and then the method of harmonic analysis is selected. After comprehensive comparison， the switching function method is selected as the main method of harmonic analysis. According to the definition of the switching function and the converter device has discrete sampling and modulation switching characteristics， its input current waveform and output voltage waveform can be represented by many switching functions and sine function modulation waveforms. This modulation waveform can be used after triangular transformation. Obtain harmonic characteristics. The process of the switching function of the voltage and current of the three-phase six-pulse converter device is deduced in detail， and the switching function is suitable for commutation and non-commutation conditions， the symmetrical and faulty switching function expressions， and the establishment of the voltage An example analysis is carried out with the switching function model of the current.

[Keywords]harmonic analysis; converter station; switching function method; failure analysis

±600 kV及以下的直流输电电压被称为高压直流（HVDC），±600 kV以上的直流输电电压被称为特高压直流（UHVDC）。随着大容量、远距离、多回交直流并联运行在输电过程中的优势，但直流设备也成了系统中的较大谐波源。换流站的换流装置就是大功率、非线性电子元器件，在系统中产生大量非特征谐波，对供电质量是一种“污染”。谐波问题也成为了直流输电系统一个很突出并且很重要的技术问题。

1 HVDC系统谐波分析方法选择

IHA法虽然比较简单，由于采用Guass-Seidel迭代算法，收敛性较差，所作的改进措施又会使计算复杂化，所以不适用于交流谐波阻抗较大或精度要求高的情形。文献表明，这一方……