Fault Location Of Underground Transmission Line Based On VMD-GST-TEO In Coal Mine

The underground transmission line of coal mine undertakes the important task of supplying power to the underground load and is the basis of maintaining the normal operation of coal mine,Aiming at the problem of difficult fault location and backward means of underground transmission line in coal mine,this thesis puts forward double terminal traveling wave method based on VMDGST-TEO for fault location of underground transmission line in coal mine.Firstly,this thesis analyzes the generation and propagation of fault traveling wave of transmission line in coal mine,discusses the refraction and reflection process of traveling wave and phase mode transformation.Researching the principle,characteristics and advantages of EMD and VMD algorithm,and discussing the selection of K value in VMD algorithm.By setting different K values and comparing their respective decomposition effects,selecting the K-value corresponding to the best decomposition effect,and decomposing the simulated fault traveling wave signal with EMD and VMD.Comparing the decomposition effect of the two methods,finally,VMD algorithm is selected to deal with the fault traveling wave.In order to further deal with the modal components obtained from VMD decomposition,GST(generalized S-transform)is adopted in this thesis.Researching the principle and advantages of generalized S transform,deducing S transform from two aspects of wavelet transform and fourier transform,and then improving S transform to obtain generalized S transform according to the shortcomings of S transform,which proves that generalized S transform inherits the advantages of wavelet transform and fourier transform,and at the same time overcomes the disadvantages of S transform,and has flexible regulation characteristics for frequency resolution and time resolution.For the identification of fault traveling wave mutation point,Teager energy operator method is used,and deriving the basic principle of Teager energy operator method and the process of signal demodulation.Finally,the method of double terminal traveling wave fault location of coal mine based on VMD-GST-TEO is proposed.In this thesis,PSCAD/EMTDC and MATLAB software are used for simulation analysis.By building the underground transmission line model of coal mine and simulating the fault conditions of single-phase short circuit,two-phase short circuit and three-phase short circuit respectively,the fault location is carried out.Researching the influence of different transition resistance on the fault location method proposed in this thesis,and comparing the location results of the method proposed in this thesis with other methods.It is proved that the method proposed in this thesis has high accuracy for various fault situations and is not affected by the transition resistance.Compared with other methods,the accuracy of the method proposed in this thesis is also guaranteed.