Research On Single Ended Traveling Wave Fault Location Of HVDC Grounding Electrode Lines

High-voltage direct current(HVDC)transmission because of its unique advantages,is developing rapidly in our country.The grounding system is an important part of HVDC transmission system,grounding electrode line once the failure will affect the power supply reliability of the HVDC transmission system.However,the grounding electrode line fault protection with DME remains reliability is not high,easy to misoperation,ranging accuracy also needs to be further improved.Using fault point transient traveling wave signal can realize error accurate range,but its application in the grounding electrode line fault location study in-depth and comprehensive.For HVDC grounding electrode line,in this paper,the research uses the fault generated transient travelling wave to realize HVDC grounding electrode line of single ended traveling wave fault location.First analyzed the HVDC grounding electrode line fault transient travelling wave and HVDC grounding electrode line fault mechanism of initial traveling wave modulus and initial travelling wave fault propagation characteristics;According to the HVDC grounding electrode line fault transient travelling wave propagation characteristics,this paper introduces the HVDC grounding electrode line single-ended travelling wave ranging basic principle,and put forward two kinds of suitable for HVDC grounding electrode line of single ended traveling wave distance measuring algorithm:ranging algorithm based on mathematical morphology and ranging algorithm based on multi-resolution correlation function,the former by using morphological gradient transformation processing line capable of filtering waves,not only can extract the starting time of signal mutation points,can distinguish the wave head polarity of line at the same time,the latter using multi-resolution processing fault traveling wave window,make full use of window width when their respective advantages,can accurately extract the fault point,at the same time through the correlation function extreme value point can accurately identify the second reverse the polarity of the traveling wave,using two kinds of algorithm for fault point moment can realize single ended traveling wave fault location;Built based on PSCAD/EMTDC platform,HVDC transmission system simulation model of the HVDC grounding electrode line fault transient travelling wave propagation characteristic and HVDC grounding electrode line single ended traveling wave distance measuring algorithm simulation,the simulation results show that two kinds of algorithms has high ranging precision.Ranging algorithm based on mathematical morphology and ranging algorithm based on correlation function proposed in this paper have different features,simulation show that both algorithms can realize HVDC grounding electrode line of single ended traveling wave fault location,and range accuracy is higher,on a line for the study of HVDC grounding fault protection provides a new solution,and can be applied to the operation and communication pole,etc.