Fault Location Of HVDC Line Based On S-transform Spectrum Energy Entropy

The research about Fault Analysis and Location of HVDC Transmission System is an important part of the development of HVDC transmission system.With the upgrading of grid voltage,Power transmission distance,transmission capacity,ect.HVDC has become the development trend of smart grid,and a major factor restricting its development is the research and positioning of HVDC transmission system fault,which has become a hot issue.Firstly,Based on the research background and significance of fault location of HVDC transmission system,and summarizes the existing domestic and foreign research methods.In order to fully analyze and study the fault problem of DC transmission system,the basic model of common single dipole DC transmission system is established respectively.According to the fault traveling wave propagation rules and the fault characteristics under different DC transmission system operating modes,it is proposed to use S transform to extract the mains frequency and current signal group of the fault time before and after the fault,and solve the DC transmission fault in time domain Precise extraction of main frequency of traveling wave signal.The spectral energy entropy is used to solve the problem that the frequency of the system is mixed and difficult to be identified due to the coupling and reflex reflection between the traveling wave modes,and the fault points are accurately positioned.Finally,the model of ± 500 KV unipolar and bipolar DC transmission system was established by PSCAD / EMTDC.The simulation and data acquisition of DC transmission system are carried out.The data is analyzed and analyzed by using the method of S-transform spectral energy entropy.The results show that the minimum error rate is 0.0018% and the average error rate is 0.09776%.It has a high accuracy and is an effective method for fault location of high voltage DC system.