含VSC-HVDC交直流混联电力系统三相谐波潮流统一算法

Unified Newton’s Solution to Three-phase Harmonic Power Flow of VSC-HVDC Based AC/DC Power Systems

将基于电压源换流器的高压直流（voltage source converter based high voltage direct current,VSC-HVDC）输电系统谐波潮流算法从单相扩展到三相,提出含VSCHVDC交直流混联电力系统三相谐波潮流统一算法。为计及直流系统中换流变压器和VSC的不对称,分别建立它们的三相谐波模型,而平衡的交流系统采用对称分量谐波模型。交直流系统的对称与不对称部分之间以相-序分量转换方程为接口。交流侧的三相基波和谐波量以及直流侧的直流、基波和谐波量用牛顿法统一求解。该算法保持了VSCHVDC单相谐波潮流算法的高精度和相对于时域仿真法的计算速度优势,完善了VSC-HVCD的谐波模型,使其更加通用且符合实际情况,计及了不对称所引起的交、直流侧非特征谐波,是VSC-HVDC谐波分析频域法的进一步发展。

This paper extends the harmonic power flow of voltage source converter based HVDC（VSC-HVDC） power transmission systems to three phases, yielding a new algorithm called three-phase harmonic power flow of VSC-HVDC based AC/DC power systems（VSC-HVDC TPHPF）. To handle the three-phase asymmetry of VSC-HVDC, the converter transformers and VSCs were represented by their three-phase harmonic models, while the balanced AC system was modeled by symmetrical components at harmonic orders. The phasesequential component transformation equations were used as the interface between the symmetrical and unsymmetrical parts. The three-phase fundamental and harmonic variables of the AC side, together with the DC, fundamental, and harmonic variables of the DC side were solved simultaneously by Newton＇s method. While maintaining the computational efficiency advantage over time-domain simulation and the good accuracy of its single-phase version, the proposed algorithm further develops the frequency-domain harmonic analysis method for VSC-HVDC by including the AC and DC side non-characteristic harmonics and making the entire harmonic model more general and realistic.