摘要
模块化多电平换流器(modular multilevel converter,MMC)在中高频下可能呈现负阻尼特性,是诱发柔直并网系统发生中高频谐振的主要原因。现有谐振抑制措施无法精确定位影响MMC阻抗特性的关键因素,导致适用场景较为单一。为此,提出一种基于Sobol阻抗灵敏度分析的中高频谐振抑制策略,该方法能够定量判别不同控制参数及运行工况下影响MMC阻抗特性的主导因素,实现柔直并网系统的谐振溯源。首先,基于谐波线性化方法建立了柔直并网系统交流侧阻抗精确模型;其次,利用Sobol算法对MMC的阻抗灵敏度进行计算,获得影响其阻抗特性的关键影响因素。然后,考虑多影响因素的参数联合调整稳定域,提出适用于柔直并网系统的中高频振荡抑制策略。最后,在PSCAD中搭建了柔直并网系统的仿真模型,对比验证了阻抗灵敏度计算方法的正确性和所提谐振抑制策略的有效性。
Modular multilevel converter(MMC)may exhibit its negative damping characteristics at the medium and high frequencies,which is the main reason for inducing the medium and high frequency resonance in the flexible and direct grid connected systems.The existing resonance suppression measures can not accurately locate the key factors affecting the impedance characteristics of the MMC,resulting in the single application scenario.Therefore,this paper proposes a medium and high frequency resonance suppression strategy based on the Sobol impedance sensitivity analysis.This method quantitatively identifies the dominant factors that affect the impedance characteristics of the MMC under different control parameters and operating conditions,realizing the resonance traceability of the flexible and direct grid connected systems.Firstly,based on the harmonic linearization method,the accurate AC impedance model of the flexible and direct grid connected system is established;Secondly,the Sobol algorithm is used to calculate the impedance sensitivity of the MMC and the key factors affecting its impedance characteristics are obtained.Then,considering the joint adjustment of the stability region of the parameters of the multiple influencing factors,a medium and high frequency oscillation suppression strategy suitable for the flexible and straight grid connected systems is proposed.Finally,a simulation model of the flexible and direct grid connected system is built in the PSCAD,which verifies the correctness of the impedance sensitivity calculation method and the effectiveness of the proposed resonance suppression strategy.
作者
王洪耀
张英敏
廖建权
王渝红
WANG Hongyao;ZHANG Yingmin;LIAO Jianquan;WANG Yuhong(College of Electrical Engineering,Sichuan University,Chengdu 610065,Sichuan Province,China)
出处
《电网技术》
EI
CSCD
北大核心
2023年第10期4311-4322,共12页
Power System Technology
基金
国家重点研发计划项目(2021YFB2400800):“响应驱动的大电网稳定性智能增强分析与控制技术”。
关键词
柔性直流并网系统
Sobol算法
阻抗灵敏度
参数协调优化
谐振抑制
flexible DC grid connected system
Sobol algorithm
impedance sensitivity
parameter coordination and optimization
resonance suppression
