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The purpose of this paper is to describe a technique for modeling transformer internal faults using transmission line modeling (TLM) method. In this technique, a model for simulating a two winding single phase transformer is modified to be suitable for simulating an internal fault in both windings.

TLM technique is mainly used for modeling transformer internal faults. This was first developed in early 1970s for modeling two‐dimensional field problems. Since, then, it has been extended to cover three dimensional problems and circuit simulations. This technique helps to solve integro‐differential equations of the analyzed circuit. TLM simulations of a single phase transformer are compared to a custom built transformer in laboratory environment.

It has been concluded from the real time studies that if an internal fault occurs on the primary or secondary winding, the primary current will increase a bit and secondary current does not change much. However, a very big circulating current flows in the shorted turns. This phenomenon requires a detailed modeling aspect in TLM simulations. Therefore, a detailed inductance calculation including leakages is included in the simulations. This is a very important point in testing and evaluating protective relays. Since, the remnant flux in the transformer core is unknown at the beginning of the TLM simulation, all TLM initial conditions are accepted as zero.

The modeling technique presented in this paper is based on a low frequency (up to a few kHz) model of the custom‐built transformer. A detailed capacitance model must be added to obtain a high‐frequency model of the transformer. A detailed arc model, aging problem of the windings will be applied to model with TLM + finite element method.

Using TLM technique for dynamical modeling of transformer internal faults is the main contribution. This is an extended version of an earlier referenced paper of the authors and includes inductance calculation, leakages calculation, and BH curve simulation while the referenced paper only includes piecewise linear inductance values. This modeling approach may help power engineers and power system experts understand the behavior of the transformer under internal faults.

The purpose of this study is to develop a reliable finite element algorithm based on the transmission line method (TLM) to solve the nonlinear problem in electromagnetic field calculation.

In this paper, the TLM has been researched and applied to solve nonlinear iteration in FEM. LU decomposition method and the Jacobi preconditioned conjugate gradient method have been investigated to solve the equations in transmission line finite element method (FEM-TLM). The algorithms have been developed in C++ language. The algorithm is applied to analyze the magnetic field of a long straight current-carrying wire and a single-phase transformer.

FEM-TLM is more effective than traditional FEM in nonlinear iteration. The results of FEM-TLM have been compared and analyzed under different calculation scales. It is found that the LU decomposition method is more suitable for FEM-TLM because there is no need to repeatedly assemble the global coefficient matrix in the iterative solution process and it is not affected by the disturbance of the right-hand vector.

An effective algorithm is provided for solving nonlinear problems in the electromagnetic field, which can save a lot of computing costs. The efficiency of LU decomposition and CG method in FEM-TLM nonlinear iteration is investigated, which also makes a preliminary exploration for the research of FEM-TLM parallel algorithms.

This paper presents the use of transmission‐line modelling ‐ time domain (TLM‐TD) method to analyse the fields in mode stirred reverberation chambers excited by wires. It will be shown how the fields inside the chamber are distributed for a large range of excited frequencies. The work intends to develop a numerical procedure to verify the effectiveness and usefulness of the TLM method to electromagnetic compatibility problems. The numerical model presented here is based on the classical symmetrical condensed 3D node. The simulations will be compared with method of moments results obtained in available benchmark data. Some comments are made on comparisons between the two techniques.

A super‐condensed TLM node for modelling inhomogeneous anisotropic media on an arbitrarily graded mesh without using stubs is developed. It requires less storage, computationally is more efficient and can operate on a higher time step than existing TLM nodes. Complete derivation, implementation and validation of the new node are presented in the paper.

The two‐dimensional discrete Huygens’ modelling or TLM simulation is presented for the TE electromagnetic field problems. The TLM element or node with variable traveling speed and characteristic impedance is applied to several practical problems including scattering at the edge of a wall and over periodic grids or grooves, wave propagation along a dielectric structure, and a mode coupling between two parallel optical waveguides. The TLM solutions are compared with the theoretical ones or the results of other numerical methods and reasonable agreement is achieved.

The paper seeks, by means of measurement and modelling, to evaluate frequency dependent per‐unit‐length parameters of conductive textile transmission line (CTTL) for wearable applications and to study deterioration of these parameters when CTTL is subjected to washing.

The studied transmission line is made of Nickel/Copper (Ni/Cu) plated polyester ripstop fabric and is subjected to standard 60°C cycle in a commercial off‐the‐shelf washing machine. The per‐unit‐length parameters (resistance and inductance) and characteristic impedance of the line are extracted from measurements before and after washing. Using the measurement data an equivalent circuit is created to model the degradation of the line. The circuit is then integrated in a three‐dimensional transmission line matrix (TLM) model of the transmission line.

Both an electrical equivalent circuit and a TLM model are developed describing the degradation of the conductive textile when washed. A severe deterioration of the electrical parameters of the line is noticed. Experimental and modelling results are in good agreement in the addressed frequency band.

Analysis is performed for frequencies up to 10 MHz. The developed TLM model can be used to conduct parametric studies of the CTTL. To counteract the degradation of the line, protective coating is to be considered in further studies.

This paper extends knowledge of the subject by experimental and simulation‐based characterization of the CTTL when subjected to washing cycles.

In this paper, thermal analysis for a 1,200 A, 3.3 kV insulated gate bipolar transistor (IGBT) module was investigated and analysed using the three‐dimensional transmission line matrix (3D‐TLM) method. This paper also reviews the present status of the use of various thermal heat spreaders such as AlSiC MMC, Cu‐Mo and graphite‐Cu MMC and compares these with copper based heat spreaders and the use of aluminium nitride (AlN), diamond and BeO as substrates and their effect to dissipate the heat flux in heat sources localised in IGBT module design. The TLM method was found to be a versatile tool which is ideally suited to the modelling of many power electronic devices and which proved very useful in the study of transient thermal effects in a variety of device structures.

To study the advantages of a modular approach to packaging‐machine design.

Introduces the modular approach of this German company, with particular emphasis on its packaging robots and vision system. Uses a selection of food and pharmaceutical applications to illustrate the flexibility, capability and throughput of these compact packaging lines. Briefly, mentions other innovative features of the company's product range.

The company has reduced its top‐loading range of packaging machinery to just seven modules, of which a two‐ and a four‐axis robot greatly assist operational flexibility. A patented counterflow conveyor system unites products and packing boxes in a space‐saving layout. The de‐central control system reduces installation costs and assists trouble‐shooting.

Illustrates the power of robot technology in achieving a new approach to a particular type of automated machinery.

As commercial and military aircraft continue to be subject to direct lightning flashes, there is a great need to characterize correctly the electrical currents and electric potential fluctuations on an aircraft to determine alternative design approaches to minimizing the severity of the lightning-aircraft dynamics. Moreover, with the increased severity of thunderstorms due to global warming, the need arises even more to predict and quantify electrical characteristics of the lightning-aircraft electrodynamics, which is normally not measurable, using a reliable electric model of the aircraft. Such a model is advanced here. The paper aims to discuss these issues.

The case considered in this paper is that of an aircraft directly attached to an earth flash lightning channel. The paper develops a new approach to modelling the aircraft using electric dipoles. The model has the power to represent sharp edges such as wings, tail ends and radome for any aircraft with different dimensions by using a number of different sized dipoles. The distributed transmission line model (TLM) of the lightning return stroke incorporating the distributed aircraft model is used to determine aircraft electrical elements and finally the electric current induced on the aircraft body due to lightning's interaction with the aircraft. The model is validated by the waveform method and experimental results.

The dipole model proposed is a very powerful tool for minute representation of the different shapes of aircraft frame and to determine the best geometrical shape and fuselage material to reduce electric stress. This charge simulation method costs less computer storage and faster computing time.

The paper for the first time presents a computer-based simulation tool that allows scientists and engineers to study the dynamics of voltage and current along the aircraft surface when the aircraft is attached to a cloud to ground lightning channel.

The purpose of this study is to numerically examine the heat transfer and transport of space charges in the solid insulating materials [low density polyethylene (LDPE), flame retardant type 4 (FR4), Polytetrafluoroethylene (PTFE)] using the transmission line modeling (TLM) method. Besides, a comprehensive study is performed on the mutual influences of heat transfer and space charges transport within the solid dielectric bulk.

The obtained governing equations including continuity and circuit equations are coupled with heat transfer equations, and they are solved via fourth-order Runge–Kutta method.

The electric potential and field, current density and temperature distribution are calculated. It is shown that compared with FR4 and PTFE, the temperature increment rate in LDPE is much lower. Moreover, the heat transfer in the solid insulating materials bulk increases the homo-charges density and temperature in the vicinity of electrodes. Hence, the reduction in electric field is reflected in the potential deformations in the proximity of electrodes. Furthermore, where the electric field is maximized, the temperature is minimized.

This study is restricted to two-dimensional problems.

Interestingly, because of the lower temperature in LDPE, the current density and their increment rates in LDPE are much lower than that in FR4 and PTFE dielectric materials.