Research On Synthesis Fault Location Method Of DC Grounding Electrode Lines

High voltage direct current(HVDC)technology is developing rapidly all over the world,and the DC grounding electrode is an important part of it.If the line fails,it will have a great impact on the whole HVDC transmission project.Therefore,in order to ensure the safe and stable power supply of the DC transmission project,it is necessary to monitor and locate the fault of the grounding lead in real time.In this paper,aiming at the particularity of the DC grounding system,in order to realize the fault grounding of the grounding lead,the main work is as follows:(1)The theoretical basis of the fault grounding of the DC grounding lead is analyzed,including the generation mechanism of the grounding lead fault,the type and characteristics of the traveling wave source which can be used for fault location,and the characteristics of traveling wave propagation in the long line.(2)According to the characteristics of the fault of the grounding system under different operating modes,the method of integrated fault location of high voltage DC grounding lead is proposed,namely using the external pulse signal source as the basis for fault location of the balance operation mode,and making a detailed analysis of the pulse signal;while in the non balanced operation mode using the fault transient traveling wave for fault location combining the impedance monitoring in principle,proposing a new comprehensive single ended fault location method based on impedance method and traveling wave method.This two methods can meet the requirements of fault location accurately of DC grounding lead under different operating modes,providing a new possibility for the realization of DC grounding lead’s fault location.(3)According to the parameters of grounding electrode lead in practical engineering,the PSCAD / EMTDC simulation software was used to build a simulation model of the HVDC transmission system,for simulating the line faults and analyzing the integrated method of the HVDC grounding line.And with the help of MATLAB software,the analysis based on the fault waveforms of different simulation cases show that the model built is consistent with the fact and the methods are feasible.And the proposed methods provide a theoretical foundation for the realization of DC grounding wire on-line monitoring.The proposed fault location methods in different operating modes of DC grounding wire have their own characteristics.The simulation results show that the proposed method can achieve the requirements of DC grounding lead fault location accurately and reliably.It provides a feasible research direction for the safe and stable operation of DC grounding system.