摘要
为提高混合直流输电系统线路保护的抗干扰能力和适用范围,提出一种基于电压-电流采样轨迹的直流输电线路保护方案。首先,从理论上分析了直流线路故障时测量电压与测量电流之间的关系,揭示了区内/外故障时的电压-电流线性度差异。然后,以区外故障时电压-电流所服从的线性模型作为假设模型,将实测数据得到的采样轨迹与假设模型对应的直线进行比对,引入拟合优度指标作为特征量来量化并放大实测数据与假设模型的差异,并进一步给出直流输电线路保护方案。最后,在PSCAD/EMTDC中建模并仿真分析了多种因素对所提保护方案的影响,结果表明所提保护方案能够可靠、快速地识别直流输电线路故障,在高阻和强噪声的场景下仍可适用,且无需提取特征频带,无需双端数据严格同步,对于保护装置的采样率要求较低,易实现工程应用。
A novel HVDC line protection scheme based on voltage-current sampling trajectory is proposed to improve the anti-interference ability and application range of hybrid HVDC line protection.First,the relationship between measured voltage and current under DC line faults is analyzed,and the difference in voltage-current linearity under internal/external faults is investigated.Then,using the linear voltage-current model of external fault as the hypothesis model,the sampling trajectory obtained from the measured data is compared with the hypothesis model,and the goodness of fit index is introduced as the characteristic quantity to quantify and amplify the difference between the measured data and the hypothesis model.Subsequently,the overall configuration scheme of the HVDC line protection is given.Finally,the influence of various factors on the proposed protection scheme is investigated by modeling and simulation in PSCAD/EMTDC.Simulation results verify that the proposed protection can reliably and quickly identify the faults in DC transmission line and can also be applied to high-resistance faults and strong-noise scenarios.It does not need characteristic frequency-band extraction and strict two-end data synchronization,and its lower sampling frequency makes it conducive to realizing engineering applications.
作者
戴志辉
石旭
DAI Zhihui;SHI Xu(School of Electric and Electronic Engineering,North China Electric Power University,Baoding 071003,Hebei Province,)
出处
《电网技术》
EI
CSCD
北大核心
2024年第5期2179-2188,I0108,I0109-I0112,共15页
Power System Technology
关键词
混合直流输电
纵联保护
采样轨迹
线性拟合
hybrid DC transmission
pilot protection
sampling trajectory
linear fitting
