交直流系统互补谐振谐波不稳定的抑制措施

Suppression measures of harmonic instability for complementary resonance in AC/DC system

针对LCC-HVDC输电系统谐波不稳定问题,特别是由互补谐振引发的谐波不稳定现象,基于换流器开关函数调制理论,建立了交流系统阻抗、交流侧滤波器、换流变压器的谐波阻抗模型,分析了交流侧发电机台数和滤波器组数对系统谐振点的影响,进一步提出通过改变系统运行方式来破坏谐振点的谐波不稳定抑制措施。在EMTDC仿真平台上以CIGRE标准第一直流模型为例,对所提出的抑制措施进行仿真验证,仿真结果验证了所提措施的正确性和有效性。

Concerning the harmonic instability problem of LCC-HVDC transmission system,especially the phenomenon of harmonic instability caused by complementary resonance,the harmonic impedance models of AC system impedance,AC filter and converter transformer are established based on the modulation theory of converter switching function.The influence of the number of generators and filter groups on the resonance points of the system is analyzed.A harmonic instability suppression strategy is further proposed to destroy the resonance point by changing the operation mode of the system.The standard CIGRE model is established in PSCAD The simulation results verify the correctness and effectiveness of the proposed strategy.