| In the 1990 s,the voltage source converter(VSC-HVDC)technology was proposed for the first time,which used full control power electronic components in all directions.HVDC transmission technology based on voltage source converter avoids some drawbacks of conventional transmission technology.This technology is suitable for new energy transmission absorption and asynchronous AC system interconnection.Based on my working experience,it is considered that HVDC transmission technology based on voltage source converter is an effective means to solve the problem of large-capacity transmission in the future.However,overhead transmission lines are necessary for large-capacity long-distance transmission.It is inevitable that the operating environment is very bad,so the protection of transmission lines is a problem.It is very noteworthy.Among these problems,fast and accurate fault identification plays an important role,so fast and accurate fault identification of transmission lines is discussed.Firstly,the principle of HVDC transmission is deeply studied.In PSCAD,a simulation model of HVDC transmission system based on voltage source converter is constructed.Various faults of transmission lines are simulated in the simulation system,and the system characteristics are summarized through data.Secondly,through studying and introducing the theory of wavelet transform and its application in signal processing,the feasibility of applying it to fault traveling wave detection of HVDC line is analyzed.According to my work experience,the characteristics of fault time are extracted according to the changes of power grid when fault occurs,and wavelet transform is combined.The corresponding solutions are put forward.Finally,combined with my actual work,on the premise of establishing the model in PSCAD environment,and through the MATLAB wavelet toolbox to the results of in-depth analysis,confirmed the improved HVDC transmission line protection strategy,with excellent response performance. |
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