A Pilot Protection for Hybrid HVDC Transmission Line Based on Voltage-current Sampling Trajectory
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.
hybrid DC transmissionpilot protectionsampling trajectorylinear fitting
国家科技期刊平台
NSTL
万方数据
维普
