Comparing lumped and distributed parameters models in transmission lines during transient conditions

Author(s):  
A. R. J. Araujo ◽  
R. C. Silva ◽  
S. Kurokawa
2020 ◽  
Vol 4 (2) ◽  
pp. 127-138
Author(s):  
Ismael Saeed ◽  
Kamal Sheikhyounis

The modeling and calculation of a single phase-to-earth fault of 6 to 35 kV have specific features when compared with circuits with higher nominal voltages. In this paper, a mathematical analysis and modeling of a 3-phase overhead transmission line with distributed parameters consisting of several nominal T-shaped, 3-phase links with concentrated parameters replaced by 1 nominal T-shaped link were carried out. Further analysis showed that not accounting for the distributed nature of the line parameters did not cause significant errors in the assessment of the maximum overvoltage in the arc suppression in single phase-to-earth faults, and that sufficient accuracy insures the representation of the line by only 1 nominal T-shaped, 3-phase link. Such a modeling technique makes it impossible to identify the location of single-phase faults, which is the property of higher harmonic amplification of individual frequencies. Chain equivalent schemas with constant parameters are valid for a single frequency, thereby providing an opportunity to study the nature of the wave process by the discrete selection of parameters. Next in the mathematical representation, we consider the overhead transmission lines as lines with distributed parameters.


Author(s):  
Aurel-Sorin Lup ◽  
Gabriela Ciuprina ◽  
Daniel Ioan ◽  
Anton Duca ◽  
Alexandra Nicoloiu ◽  
...  

Purpose The purpose of this paper is to propose a physics-aware algorithm to obtain radio frequency (RF)-reduced models of micro-electromechanical systems (MEMS) switches and show how, together with multiphysics macromodels, they can be realized as circuits that include both lumped and distributed parameters. Design/methodology/approach The macromodels are extracted with a robust procedure from the solution of Maxwell’s equations with electromagnetic circuit element (ECE) boundary conditions. The reduced model is extracted from the simulations of three electromagnetic field problems, in full-wave regime, that correspond to three configurations: signal lines alone, switch in the up and down positions. Findings The technique is exemplified for shunt switches, but it can be extended for lateral switches. Moreover, the algorithm is able take frequency dependence into account both for the signal lines and for the switch model. For the later, the order of the model is increased until a specified accuracy is achieved. Originality/value The use of ECE as boundary conditions for the RF simulation of MEMS switches has the advantage that the definition of ports is unambiguous and robust as the ports are clearly defined. The extraction approach has the advantage that the simplified model keeps the basic phenomena, i.e. the propagation of the signal along the lines. As the macromodel is realized with a netlist that uses transmission lines models, the lines’ extension is natural. The frequency dependence can be included in the model, if needed.


2020 ◽  
Vol 11 ◽  
pp. 8-14
Author(s):  
Andrzej J. Skiba ◽  

Modelling electrical circuits by application of schemes containing elements with distributed parameters such as transmission lines has been applied in this research. Functions approximating voltage or current atmospheric discharges have been presented together with frequency spectra of these functions. The results of computer simulations obtained with the help of PSpice software have been presented for a simplified three-phase circuit subject to such discharge.


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