Fractional Lumped Parameter Modeling of Transformer Windings under VFTO

2014 ◽  
Vol 494-495 ◽  
pp. 1529-1533
Author(s):  
Gui Shu Liang ◽  
Guang Bo Zhang ◽  
Xin Liu

Very fast transient overvoltage (VFTO) is very dangerous for the transformer which is directly connected to gas insulated substations (GIS). At the same time, due to the continuous increasing of operating frequency in the power system, under the high frequencies of the transmission line calculation and simulation process, it is necessary to consider the frequency-dependent properties of the parameter. In order to study the voltage distribution in transformer windings under VFTO, a new Lumped parameter model which takes into account the fractional characteristics is proposed, named fractional lumped parameter model (FLP). The model divides each turn of transformer windings into proper sections, whose parameters are all lumped parameters. Finally it shows the correctness and validity of the model through the comparation of the experiment datas and simulation results.

2019 ◽  
Vol 105 (6) ◽  
pp. 1283-1285
Author(s):  
René Christensen

An accurate acoustic model of a tube in the millimeter or sub-millimeter size should include the losses that occur due to viscosity and thermal conduction, collectively termed thermoviscous losses. These losses are prominent in a boundary layer near the tube walls. Under the assumption that the boundary layer is thick compared to a characteristic geometry length, such as the radius for a circular cross-section, and fills out the entire cross-section, the tube can be described via a lumped parameter model. The lumped parameters have been known for several decades for a tube with circular cross-section, but the equilateral triangular tube has only been investigated in terms of transmission line parameters. The lumped parameters have here been established for the equilateral triangular tube as a truncated series solution of the transmission line parameters. One result observed is that the lumped parameter model for a triangular tube has 38% more viscous loss than a circular tube for a given area.


2001 ◽  
Author(s):  
J. Brown ◽  
M. A. Franchek

Abstract Presented in this paper is a model-based method for assessing suspension and motor health of washing machines. The diagnosis of the suspension and motor health is achieved by processing the measured dynamics of the washtub. In particular, an online adapted lumped parameter model of the washtub is used to estimate key suspension and motor parameters. These parameters are identified from the measured displacement of the washtub due to a motor pulse input prior to the beginning of the wash cycle. Comparing the estimated values to design values assesses both suspension and motor health. Included are simulation results to validate the parameter estimation process.


2014 ◽  
Vol 13 (2) ◽  
pp. 20 ◽  
Author(s):  
P. O. Cronemberger ◽  
E. P. Lima Jr. ◽  
J. A. M. Gois ◽  
A. B. Caldeira

This study aims to examine theoretically and experimentally the interior ballistics of a rifle 7.62. Three theoretical methods are employed: the Vallier-Heydenreich, which is based on empirical data tables; the lumped parameters that is represented by a differential-algebraic system of equations, describing the propellant combustion, the thermodynamics of the gas inside the gun and the projectile dynamics; and the commercial software PRODAS. The theoretical solutions furnish the pressure, the projectile velocity and the projectile position inside the gun, the maximum pressure,the muzzle velocity and the total time of the interior ballistics. The experiments measure the pressure along of the time and the projectile velocity at seven meters ahead of the barrel. The proposed lumped parameter model indicates alternatives to model the energy lost and the resistance pressure functions. The theoretical solutions are compared with experiments. A thermodynamics analysis of the energy conversion in the gun is provided. The results are analyzed and the relevance of each method is highlighted.


2010 ◽  
Vol 37-38 ◽  
pp. 1120-1124 ◽  
Author(s):  
Xiang Xu ◽  
Rui Ping Zhou

In this paper, gear dynamics theory has been introduced into the torsional vibration calculation of the marine propulsion shafting. The vibration equations of a marine gearbox were established using an extended lumped parameter model through reasonably adjusting the parameters to get the natural frequency of marine gearbox shafting gear system. The solution of the equations shows that under normal condition, the natural frequency of gear meshing transmission is high and the gearbox itself will not affect the torsional resonance. Then a virtual prototype model of marine gearbox was built by the use of ADAMAS software. The simulation results show that the proposed method could reflect the actual torsional vibration correctly. Thus, the analysis method presented in this work is available for the torsional vibration calculation of the marine gearbox.


2020 ◽  
Vol 28 (02) ◽  
pp. 2050012
Author(s):  
Daniel Gert Nielsen ◽  
Peter Risby Andersen ◽  
Jakob Søndergaard Jensen ◽  
Finn Thomas Agerkvist

Finite element methods are progressively being utilized to assist in the continuous development of loudspeakers. The core of this paper is the method of lumping certain parts of the finite element model, creating a significant reduction in the model complexity that allows for e.g. faster structural optimization. This is illustrated in the paper with a loudspeaker example where the electromagnetic parts are lumped as well as the spider. It is shown that the simplified model still matches the complex response of the full FE model at very high frequencies.


Author(s):  
S. M. Petoukhov ◽  
Tuan H. Nguyen ◽  
B. Awadh ◽  
P. M. Mathew

The objective of this study is to compare containment simulation results predicted by MAAP4-CANDU v4.0.7 and GOTHIC v7.2b for a Station Blackout severe core damage accident, when the containment dousing spray system is not credited. The input parameters (mass and energy source terms into containment) for GOTHIC were generated by MAAP4-CANDU for the Station Blackout sequence. The GOTHIC (lumped parameter model) and MAAP4-CANDU containment nodalization models were very similar, thus facilitating direct comparison of the results. Analysis of the results demonstrated that the simulation results obtained with the two codes are similar. Good agreement was obtained for the containment pressure, gas temperature and containment atmosphere composition predictions.


1971 ◽  
Vol 26 (9) ◽  
pp. 1415-1424 ◽  
Author(s):  
D. Anderson ◽  
S. Claflin ◽  
F. Winterberg

Abstract Two models for describing the operation of a magnetic travelling wave accelerator, the transmission line model and the lumped parameter model, are analyzed. For both cases the current distribution and the magnetic field are calculated. It is shown that the transmission line model can be obtained as the limiting case of the lumped parameter model. It is then assumed that a superconducting solenoid with large persistent currents is used as a projectile with a constant magnetic dipole moment. The motion of this projectile is studied in the case of ignorable flux interaction. The conditions for phase and rotational stability are obtained. It is shown that the projectile has a transverse translational instability. A derivation of the flux interaction current wave is included in the Appendix.


1999 ◽  
Author(s):  
Bei Gu ◽  
Haruhiko H. Asada

Abstract This paper presents a new lumped-parameter model based simulation that describes the dynamics of the human thermoregulatory system. This approach captures the dynamic behavior of the circulation, thermal, and neural control subsystems. These coupled dynamics have never been studied even though subsystem models have existed for some time. The simulator relates the ambient air temperature to the mean arterial blood pressure, skin blood flow, and skin temperature. Experiments are used to verify the model. The simulation results are agreed with the real time experimental measurements. Furthermore, the coupled model and the co-simulator are constructed in a modular fashion that satisfies many requirements of large-scale complex physiological co-simulation.


2014 ◽  
Vol 609-610 ◽  
pp. 1503-1507
Author(s):  
Chong Ying Lu ◽  
Jian Hua Li ◽  
Li Xin Xu ◽  
Zhi Gang Wang

The radio frequency (RF) performances of MEMS suspended spiral inductor under high overload environments are studied. Firstly, a suspended spiral inductor and its MEMS surface micromachining process which is compatible with CMOS process are developed. Then, the mechanical responses and RF performances of the inductor are simulated by ANSYS and HFSS, respectively. The simulation results show that, as the overload increases, the inductance and quality factor decrease significantly when the frequency band is closed to the resonant frequency but have no significant change when the frequency band is much lower than resonant frequency; the resonant frequency of the suspended inductor decreases monotonically with the increase of overload. A modified lumped parameter model is utilized to illustrate the simulation results, which theoretically indicates that the substrate loss is more severe than the ohmic loss as the overload increases.


2012 ◽  
Vol 190-191 ◽  
pp. 847-851
Author(s):  
Yun Xia Zhang ◽  
Ting Hao ◽  
Zhi Min He

A lumped parameter model is proposed for analysis of dynamic behavior of a Passive Hydraulic Engine Mount (PHEM) with incorporation of throttle, which is characterized by effective and efficient vibration isolation behavior in the range of both low and high frequencies. The experiments are made for the purpose of PHEM validation. The aim of simulation is to discuss the effect of throttle that the key parts of new mount. It has been shown by comparison of the numerical results with the experimental observations that the present PHEM with throttle achieves good performance for vibration isolation.


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