Research On Fault Location Method Of DC Grounding Wire By Injecting Pulse Signal

In recent years,our country continues to push forward the process of high-power,long-distance and high-capacity power transmission,which makes the high voltage direct current(HVDC)transmission rapidly development.The direct current(DC)grounding wire is an important part of HVDC transmission system.When the fault happens in DC grounding wire,it will influence the reliability of power supply and cause a big electricity cut,even make the system breakdown.Therefore,the proposed different fault location methods in different operation modes have an important significance for achieving DC grounding wire fault location.The main work is as follows:(1)The process of pulse signal spreading in DC grounding wire is analyzed in this paper,and the location principle through the injected pulse signal and the selection of pulse signal in fault location are illustrated.(2)The fault location method of active pulse injection is presented in this paper for DC grounding wire in the bipolar operation mode,correspondingly,the inactive pulse injection,which combined the pulse injection with the single-ended traveling wave fault location of A type,is used for DC grounding wire in the monopole operation mode.So the proposed methods are satisfied with the accuracy of fault location for DC grounding wire in different operation modes,which propose new possibility for fault location on DC grounding wire.(3)The grounding wire simulation model of HVDC transmission system is built by PSCAD/EMTDC.Taken metallic short-circuit fault for example,the fault location method of active pulse injection for DC grounding wire under the bipolar operation mode and the fault location method combined the pulse injection with the single-ended traveling wave fault location of A type for DC grounding wire under the monopole operation mode are simulated and analyzed.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 analysis based on simulation results show that the proposed methods can realize the fault location of DC grounding wire.And the accuracy of fault location can meet the location requirement.The proposed methods provide new solution idea for DC grounding wire while discussing its protection.