摘要
在高压直流输电系统中,当直流系统与弱交流系统相连时,会存在谐波不稳定风险。针对单极12脉动换流器,基于换流器开关函数调制理论,提出在换流变压器铁芯饱和情况下,考虑两端换流器影响的高压直流输电系统谐波不稳定风险评估方法。该评估方法计及了换流器换相过程的换相角、两端交流系统与直流系统间的相互影响。在计算直流系统等值谐波阻抗时,计及了两端换流器的换相阻抗。建立验证模型,在不同的网络参数下利用已有判据和所提判据分别进行判断,并都与时域仿真结果相对比,对比结果验证了所提评估方法的准确性与优越性。仿真结果进一步表明,系统谐波阻抗值、换相角、铁芯饱和程度等均会对系统的谐波不稳定造成影响。
In the high voltage direct current（HVDC）transmission system,there is a risk of harmonic instability when the DC system is connected to a weak AC system.For the single pole 12-pulse converter,a risk assessment method of harmonic instability in HVDC transmission system considering the effect of two-terminal converters is proposed based on the modulation theory of converter switching function,and under the condition of saturation of converter transformer core.The evaluation method takes into account the commutation angle of the commutation process and the mutual effect between the two-terminal AC system and DC system.When the equivalent harmonic impedance of the DC system is calculated,the commutation impedance of two-terminal converters is taken into account.A validation model is established,in which the existing criteria and the proposed criteria are used to make risk assessment under different network parameters and compared with the simulation results in the time domain.The comparison results verify the accuracy and superiority of the proposed evaluation method.The simulation results further demonstrate that the system harmonic impedance,commutation angles and core saturation will affect the harmonic instability of system.
作者
卢智雪
刘天琪
陈相
何川
陶艳
LU Zhixue;LIU Tianqi;CHEN Xiang;HE Chuan;TAO Yan(College of Electrical Engineering and Information Technology,Sichuan University,Chengdu 610065,China)
出处
《电力系统自动化》
EI
CSCD
北大核心
2018年第19期83-89,共7页
Automation of Electric Power Systems
关键词
高压直流输电系统
开关函数理论
谐波分析
工程判据
high voltage direct current （HVDC） transmission system
switching function theory
harmonic analysisengineering criterion
