Research On Fault Location Of DC Transmission Line Based On Time Difference Of Traveling Wave Mode-component

With the rapid development of HVDC transmission engineering,fault location of HVDC transmission lines becomes more and more important.At present,traveling wave fault location method is widely used in fault location of HVDC transmission lines because of its unique advantages,and fault location problem of traveling wave method has gradually become a research focus.Based on the analysis of relevant literature,this paper proposes an improved algorithm for fault location of HVDC transmission lines based on time difference of traveling wave mode-component.In this paper,the basic theory of traveling wave is studied,the attenuation of traveling wave and the variation of wave velocity are analyzed,and the propagation characteristics of fault traveling wave in transmission lines are summarized.Secondly,the basic principles of variational modal decomposition(VMD)and permutation entropy(PE)are analyzed,the selection of key parameters of the two is discussed,and the detection ability of nonlinear signals is verified respectively.Based on this,a fault wave-head detection scheme combining VMD and PE was proposed.The feasibility was verified by establishing a simulation model of HVDC system in PSCAD/EMTDC,and the ranging effect was compared with other wave-head detection methods.In this paper,the principle of two-terminal fault location algorithm based on time difference of traveling wave mode-component is studied theoretically,and the error influencing factors of this method are analyzed.Consider the effect of line sag and zero mode wave velocity,the improved double terminal fault location algorithm is proposed,the method of using mathematical deduction line deviation between the actual length with the theoretical solution,at the same time the use of a large number of offline data for zero mode wave velocity curve fitting,and through the iterative algorithm on the wave velocity of zero and fault distance gradually.Finally,combined with the fault wave head detection method based on VMD-PE,the improved two-terminal fault location algorithm is used for experimental analysis on the PSCAD/EMTDC simulation platform.The simulation results show that the proposed method has good resistance to transition resistance,is not affected by the clock synchronization,and has good ranging accuracy in the whole length of the line.Figure [49] table [10] reference [81]...