新型交直流输电系统谐波抑制的机理

为降低换流器产生的谐波对交流系统的影响,提出了一种可有效抑制谐波于阀侧且可降低滤波器设计难度的新型换流变压器和新的谐波抑制方案。介绍了新型换流变压器的绕组接线方式、电压偏移角的计算、绕组匝数比的确定后分析了谐波抑制的机理和有效谐波抑制对绕组谐波阻抗的要求。为验证该谐波抑制方案的可行性和正确性,建立了基于新型换流变压器和传统换流变压器的交直流输电系统的仿真模型,两个模型的阀侧和网侧电流的对比分析证明,新型换流变压器的交直流输电系统谐波抑制效果良好。

Harmonic Suppression Mechanism in the Novel AC/DC Transmission System

In the traditional HVDC transmission system,to decrease the influence of harmonics on the AC system caused by the converter,filter and reactive compensating devices were installed in the net side.In the paper,a novel converter transformer and new harmonic suppression scheme are presented,which can greatly decrease the harmonic current flowing into the AC system and the design difficulty of filter.The connection way of windings,calculation of voltage offset angle,determination of windings turn ratio are described;the harmonic suppression principle and request of windings harmonic impedance is analyzed.To verify the reliability and correctness of the harmonic suppression scheme presented,the simulation models under novel converter transformer and traditional converter transformer are established,through comparatively analyzing the currents of the net and valve sides under two models,the results indicate that the new harmonic suppression scheme has a good operational performance.