Near field coupling to shielded cable due to switching operation in substation

It is vital to study the electromagnetic coupling to shielded cable for improving electromagnetic antiinterference ability of secondary equipment in a substation.As a hybrid of method of moment(MoM)and transmission line method,a frequency domain model is put forward to study the near field coupling to shielded cable due to the switching operation in substation.Compared with the results of EMTP,the proposed method has been proven correct.Furthermore,this method overcomes the disadvantage of EMTP,which is only applicable for transient analysis of parallel conductors.As an example,the presented method is applied to evaluating the electromagnetic interference(EMI)to the shielded cable,whose shield is grounded at both ends,due to the switching operation in 500 kV air insulation substation(AIS).

Parameters Calculation of Underground Cables Using MATLAB

With the development of technology, more and more options are available for insulated cables in power systems. Different cable construction types have different impedance, voltage drop and power losses. In order to efficiently design these cable systems and adequately model them for system analysis, engineers should be able to calculate the parameters of different types of cables. Although the methods of parameters calculation are very mature, few types of software are used to calculate all these parameters for different cables. The objective of this paper is to build a user-friendly software to calculate these parameters with greater flexibility even if the users are not familiar with the methods of estimating the parameters of different types of cables. A program that is used to calculate the parameters of different cross-sections of cables is built by combining the method of estimating these parameters with the graphical user interface (GUI). Using this program, users can input or choose any type of cables, and calculate the parameters they need. In the future, more functions can be added to the program and the code could be switched to python or C# and develop a better GUI (Graphical User Interface).

Reduced technique for modeling electromagnetic immunity on braid shielding cable bundles

In this paper, an efficient multi-conductor simplification technique is proposed to model the electromagnetic immunity on cable bundles within a braid shielding structure over a large frequency range. By grouping together the conductors based on the knowledge of Z-Smith chart, the required computation time is markedly reduced and the complexity of modeling the completely shielding cable bundles is significantly simplified with a good accuracy. After a brief description of the immunity problems in shielding structure, a six-phase procedure is detailed to generate the geometrical characteristics of the reduced cable bundles. Numerical simulation is carried out by using a commercial software CST to validate the efficiency and advantages of the proposed approach. The research addressed in this paper is considered as a simplified modeling technique for the electromagnetic immunity within a shielding structure.

Comparative Study on Processing Property Between CWW CO_2 Gas Shielded Welding and SAW

Cable welding wire（CWW）CO2gas shielded welding is an innovative process arc welding with high efficiency,high quality and low consumption,in which cable wire is used as consumable electrode.CWW CO2gas shielded welding and submerged arc welding（SAW）are used for contrast studies on processing property of high strength steel A36used in ship structure.The results show that the shapes of weld seam,using CWW CO2gas shielded welding and SAW,are good and no weld defect such as air hole,flaw,slag inclusion,incomplete fusion,lack of penetration and so on are found in the weld seam.Because the rotating of arc during CWW CO2gas shielded welding process has a strong stirring effect on molten pool,the grain in the heat affected zone（HAZ）of the joints,using CWW CO2 gas shielded welding,is small.Tensile failure positions of joints by CWW CO2gas shielded welding and SAW are all in the base metal,but tensile strength of CWW CO2gas shielded welding joint is higher than that of SAW joint by an average of 2.3%.The average impact energy of HAZ,using CWW CO2gas shielded welding and SAW,is almost equal,but the average impact energy of the weld seam using CWW CO2gas shielded welding is increased by 6%,and the average impact energy of the fusion line is increased by 7%.The 180°bending tests for the joints of CWW CO2 gas shielded welding and SAW are all qualified,and the joints hardness is all less than HV 355,but hardness of CWW CO2gas shielded welding wire welding joint near the fusion line is obviously lower.It can be concluded that the properties of CWW CO2gas shielded welding are better than those of the SAW joint,and CWW CO2gas shielded welding is suitable for welding high strength steel A36used in ship structure.

A Study on the EM Leakage Arising from Braided Shielding Cable

To investigate the electromagnetic leakage caused by braided shidding cable, the finite-difference formulation of braided shielding cable for both the inner shield-conductor circuit and outer shield-ground circuit are proposed. Then, the current in shield-ground circuit induced by the transmitting signal in the cable is computed in time-domain, and the shielding effectiveness of braided shield against trapezoid signals is studied. Further more, the video EM leakage in far zone is calculated. At last, the information leakage caused by EM radiation of braided cable is intercepted and recovered using the simulation platform. It is proved that EM radiation of braided cable can give rise to information leakage. It is a key factor that should be concerned in the information secure field.