Research On Prediction Method Of Crosstalk Of Non-ideal Cable Arrangement Based On Cascade Method

In the power equipment system,the severe crosstalk condition can even endanger the stable operation of the system,reduce the reliability of the system,and cause partial failure of the system.Therefore,studying the transmission mechanism of electromagnetic crosstalk of cables and predicting the magnitude and harm of electromagnetic crosstalk have important theoretical and engineering significance for the efficient operation of electrical equipment.At present,cable crosstalk research is mostly directed to ideally arranged cables,that is,parallel arranged cables,However,the cables on the actual electronic equipment are mostly non-ideal,which makes the prediction of cable crosstalk in actual engineering difficult.Therefore,based on the segment cascade method and the equivalent electromagnetic parameter method,the cable electromagnetic coupling model is established,and the two non-ideal arrangement cables of non-parallel cables and Sag cables are analyzed.According to the above problems,in the thesis:(1)For the parallel cable,the cable crosstalk prediction method based on the moment method is studied.A multi-conductor transmission line crosstalk model is established to analyze the propagation process of the cable in the transverse electromagnetic field mode,and the transmission line equation of the parallel cable is derived.Combined with the cable port circuit,the modulus conversion method is used to obtain the parallel cable crosstalk solution,and the noise voltage is solved in combination with the terminal circuit conditions.In addition,in combination with the cable electrostatic field model and the magnetic field model,the electromagnetic parameters are obtained using the software ANSYS.(2)For non-parallel cables,a crosstalk prediction method combining cascade method and equivalent electromagnetic parameters is proposed.The cascading method is used to differentiate the non-parallel cables,and the non-parallel cables are connected to the multi-segment parallel cables.The equivalent electromagnetic matrix equation under the condition of non-parallel cables is proposed by re-deriving the multi-conductor transmission line equation.On this basis,the equivalent electromagnetic parameter matrix of the non-parallel cable is solved by the numerical method of integral method and cubic interpolation,and finally the non-parallel cable crosstalk is solved by combining the moment method.(3)For the sag cable,a crosstalk prediction method combining cascading method and Monte Carlo method is proposed.The cascading method is used to differentially differentiate the sag cable,and the sag cable is discretized into a finite number of multi-segment cables;the parameter probability distribution of the sag cable is obtained by convolution.Combined with the Monte Carlo method,the spatial position is taken as the basic element to obtain the equivalent electromagnetic parameter matrix in the case of a sag cable.In addition,five factors of cable crosstalk are analyzed.Combined with orthogonal experiment method,the correction of sampling position points based on Monte Carlo method is qualitatively proposed.In addition to the simulation verification of the electromagnetic simulation software CST,this thesis also combines the darkroom experiment method to verify the effectiveness of the proposed algorithm by extracting the cable crosstalk from the vector network analyzer.For the non-parallel cable crosstalk,the trend of the cable solved by the algorithm in this thesis is consistent with the experimental results,and it is closer to the experimental value in the high frequency band than the traditional cable algorithm.For the sag cable crosstalk,compared with the traditional algorithm,the results of this thesis are closer to the experimental value in the low frequency or the high frequency,the accuracy is higher,and the error is reduced by up to 30dB,which proves the effectiveness of algorithm of this thesis.