| With the rapid development of 5g mobile communication technology,in recent years,the State Grid Corporation of China is building an energy Internet in an all-round way,strengthening the digital and information stra-tegic layout of smart grid and distribution grid,and continuously promot-ing the power line communication technology in low-voltage grid,accom-panied by the electromagnetic compatibility problem.Cable and equip-ment,cable and cable coupling interference phenomenon can be seen al-most everywhere.The crosstalk between cables will not only cause inter-ference to the transmission signal,but also may cause information leakage.In order to ensure the safe transmission of information in the communica-tion process,it is particularly important to study the crosstalk coupling be-tween cables.Based on the above requirements,the main research work of this paper is as follow:1.Studied Π The crosstalk between the cables of type a layout.Firstly,the power line communication channel model and the parallel cable bundle crosstalk coupling model are established based on the multi conductor transmission line equation.The cable crosstalk model and power line chan-nel model are combined to derive the model Π Finally,the crosstalk model of the cable is established,and the experimental measurement method is used to verify the transmission performance of the analog signal Π At the same time,CST electromagnetic simulation method is used to verify the transmission performance of digital signal Π The coupling signals obtained by the two methods are basically consistent with the model calculation re-sults,which verifies the correctness of the proposed model.2.A new sparrow search algorithm(SSA)is used to optimize the sup-port vector regression(SVR)model to establish the crosstalk model be-tween cables and predict the crosstalk voltage.By using the excellent abil-ity of support vector regression model to deal with nonlinear adaptability problems,the mapping between various factors affecting cable crosstalk and cable crosstalk value is established,so as to predict cable crosstalk value.At the same time,SSA and grid search method are used to optimize the parameters of support vector regression model to find the optimal so-lution.The experimental results show that in terms of prediction accuracy,the mean absolute percentage error(MAPE)and mean square error(MSE)of the test data are calculated,and the commonly used grid search method is used to optimize the support vector regression.The established crosstalk prediction model has MAPE=0.4438,MSE=0.0136,and the correlation coefficient is 88%,The cable crosstalk prediction model based on sparrow search algorithm optimized support vector regression model has MAPE=0.1287,MSE=0.0013,and the fitting degree of the data is as high as 99%.Compared with the grid search method optimized support vector regression prediction model,the sparrow search algorithm optimized support vector regression model has higher accuracy and better fitting degree.It can ac-curately predict the crosstalk voltage between cables.3.The coupling effect of transmitting carrier signal on the cable is eval-uated.The software system for calculating the crosstalk value of cables is developed.Through the visual front-end interface,any user can input the parameters that affect the crosstalk system in the system interface,so as to obtain the crosstalk between cables conveniently and efficiently,and re-duce the learning cost of users;The bit error rate(BER)of the crosstalk signal on the adjacent cable caused by the crosstalk and the original signal on the crosstalk line is calculated when the SNR changes in the Gaussian channel,and the coupling and security between the cables are evaluated according to the BER;The S21 parameters of cable crosstalk under differ-ent cable spacing are calculated,and the influence of cable spacing on the line to line coupling is analyzed;This paper designs the cable coupling transmission experiment,analyzes the influence of signal frequency,signal waveform,cable length and other factors on the time-domain crosstalk sig-nal between cables by using experimental measurement and simulation methods,intuitively analyzes the variation law of the coupling signal be-tween cables from the time-domain perspective,summarizes the power line layout scheme conducive to information security transmission,and puts forward some suggestions. |
