Research On Crosstalk Of Trackside Signaling Cable Based On Multi-port Network Theory And Method Of Moment

With the development of the railway in China,the application of railway signaling equipment has increased greatly,the frequency band of signaling equipment has been widened,and the signaling equipment becomes more sensitive,all of which are bringing more and more electromagnetic compatibility(EMC)problems.Signaling cable is widely used in railway field as a most common signal transmission way between each signaling equipment.Due to the limited space in the trackside cable trough and the complex trackside electromagnetic environment,the signaling cable is very frequently interfered.To ensure the normal operation of the signaling equipment,it is necessary to study the crosstalk between signaling cables.Firstly,this thesis presents a crosstalk analysis method combining multi-port network theory and method of moment(Mo M)for a complex system with parallel distribution of multiple shielded cables.The concrete steps are as follows: firstly,the traditional multi-port network crosstalk model is optimized by the block-cascaded method,and a cascade form multi-port network model is proposed.Compared with the traditional multi-port network model,the new model has a great improvement in computational complexity,generality and expansibility.Then a method of extracting distribution parameters between cables based on Mo M is derived,and the singularity in the algorithm is processed by the multi-point partition method.Next,virtual nodes are introduced to transform the distribution parameters into transmission functions in the model.Finally,by comparing with the actual measurement results and the simulation results of the electromagnetic topology method,it is verified that the proposed model and algorithm have a preferable accuracy in analyzing the crosstalk problem of signaling cables.Secondly,this thesis uses the proposed model and algorithm to calculate the crosstalk coupling coefficient of signaling cable in various situations,such as different grounding modes of shield layer,different grounding impedances of shield layer and core wire,and different positions inside the metal shell.By comparing the simulation results with the theoretical analysis results,the effect of the above factors on signaling cable crosstalk is summarized.Finally,with the consideration of the actual situation of the railway field,the crosstalk coupling coefficient with different wiring modes of the trackside signaling cables and different grounding modes of the shield layer is simulated according to the novel model and algorithm.By combining with the simulation results and the actual situation,some optimization suggestions are put forward for the grounding and wiring modes of the signaling cables along the railway trackside.