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Articles 1 - 13 of 13
Full-Text Articles in Engineering
A Physics-Based Model For Snapback-Type Esd Protection Devices, Xin Yan, Seyed Mostafa Mousavi, Li Shen, Yang Xu, Wei Zhang, Sergej Bub, Steffen Holland, Daryl G. Beetner
A Physics-Based Model For Snapback-Type Esd Protection Devices, Xin Yan, Seyed Mostafa Mousavi, Li Shen, Yang Xu, Wei Zhang, Sergej Bub, Steffen Holland, Daryl G. Beetner
Electrical and Computer Engineering Faculty Research & Creative Works
A simplified physical-based model for deep-snapback transient voltage suppressors (TVS) is developed in this article. While based on physics, the number of parameters and components is minimized, so the model can be tuned easily from available measurements of the packaged TVS. SPICE convergence issues seen in previous snapback device models are eliminated by adding nonlinear damping components to the model. No convergence issues were seen among any of the simulations performed for this study, which includes transmission-line pulse tests with multiple levels and rise times. The proposed model was used to represent two different TVS devices and was validated in …
Electric Power System Studies For A Multi-Mw Pv Farm And Large Rural Community With Net Zero Energy And Microgrid Capabilities, Evan S. Jones, Oluwaseun M. Akeyo, Keith Waters, Dan M. Ionel
Electric Power System Studies For A Multi-Mw Pv Farm And Large Rural Community With Net Zero Energy And Microgrid Capabilities, Evan S. Jones, Oluwaseun M. Akeyo, Keith Waters, Dan M. Ionel
Power and Energy Institute of Kentucky Faculty Publications
Solar photovoltaic (PV) systems are currently being deployed at an accelerated rate because of their cost-competitiveness and environmental benefits, which make them a prime candidate for local renewable energy generation in communities. Microgrids can help accommodate for the problems that accompany PV systems, such as intermittency due to weather, by coordinating different distributed energy resources (DERs), while islanded or by drawing power from the utility while in grid-connected mode. An islanding option is also important for resilience and grid fault mitigation, even if other DERs are not present within the system. This paper studies the potential benefits that a multi-MW …
Network Equivalents Applied To Transient Analysis Of Large Distribution Systems, Ghassan Abdul-Hussein Bilal
Network Equivalents Applied To Transient Analysis Of Large Distribution Systems, Ghassan Abdul-Hussein Bilal
Dissertations
Frequency domain (FD) methods for electromagnetic transient analysis of electric power systems offer outstanding simplicity and accuracy when dealing with distributed parameter elements and components that exhibit frequency-dependent behavior. However, the use of FD methods is usually restricted to the simulation of small and simple networks, since it is commonly believed that their application implies a very large computational burden when compared to time domain methods. This study demonstrates that FD methods can accommodate the detailed simulation of large distribution networks within acceptable computer times and in a very straightforward manner, thus offering an attractive complement or alternative to common …
Parameter Determination And Modeling Of Transformer Windings For Fast Transients Including Frequency Dependent Effects, Yazid Al-Kraimeen
Parameter Determination And Modeling Of Transformer Windings For Fast Transients Including Frequency Dependent Effects, Yazid Al-Kraimeen
Dissertations
Power transformers are static devices capable of transferring energy from one electrical circuit to another by means of electromagnetic induction at the same frequency. The most common application of transformers in an electric power system is to step up or down the voltage level of an electric grid. This is essential for the efficient transmission and distribution of electricity from generating plants to different types of consumers. Electrical energy used in residential, commercial and industrial settings is delivered to consumers by means of transformers, which normally operate 24 hours a day, 365 days a year. Therefore, design improvements that result …
Temporal Preconditioners For Marching-On-In-Time-Based Time Domain Integral Equation Solvers, Hüseyi̇n Arda Ülkü
Temporal Preconditioners For Marching-On-In-Time-Based Time Domain Integral Equation Solvers, Hüseyi̇n Arda Ülkü
Turkish Journal of Electrical Engineering and Computer Sciences
Temporal preconditioners to stabilize the marching-on-in-time (MOT)-based time domain integral equation (TDIE) solvers are proposed. Exponentially decaying functions are used as temporal preconditioners and the proposed scheme is applied to analyze scattering from perfect electrically conducting objects using the second-order formulation. The effectiveness of the proposed scheme is demonstrated via numerical examples. It is shown that the temporal preconditioners stabilize the MOT system and the solution. In addition, the initial condition problem of TDIEs is investigated by extending the second-order formulation of the time domain electric field integral equation to the time domain magnetic and combined field integral equations.
Embedding The Behavior Macromodel Into Tdie For Transient Field-Circuit Simulations, Huan Huan Zhang, Li (Lijun) Jun Jiang, He Ming Yao
Embedding The Behavior Macromodel Into Tdie For Transient Field-Circuit Simulations, Huan Huan Zhang, Li (Lijun) Jun Jiang, He Ming Yao
Electrical and Computer Engineering Faculty Research & Creative Works
A novel transient field-circuit simulation method based on the time-domain integral equation (TDIE) and circuit macromodels is proposed. The traditional field-circuit simulation process constructs Kirchoff's equations for linear or nonlinear lumped circuits, which cannot handle problems with unknown circuit structure. The proposed method creates parametric behavior macromodels to represent the port constitutive relations of the circuits. Artificial neural network technique is adopted to estimate the model parameters based on the known port voltages and currents. Then, the obtained macromodel is coupled with TDIE that describes the behavior of electromagnetic subsystem to form the equations of a whole system, which can …
A Hybrid Electromagnetics-Circuit Simulation Method Exploiting Discontinuous Galerkin Finite Element Time Domain Method, Ping Li, Li (Lijun) Jun Jiang
A Hybrid Electromagnetics-Circuit Simulation Method Exploiting Discontinuous Galerkin Finite Element Time Domain Method, Ping Li, Li (Lijun) Jun Jiang
Electrical and Computer Engineering Faculty Research & Creative Works
A hybrid electromagnetics (EM)-circuit simulation method employing the discontinuous Galerkin finite element time domain (DGFETD) method is developed to model single lumped port networks comprised of both linear and non-linear elements. The whole computational domain is split into two subsystems: one is the EM subsystem that is analyzed by DGFETD, while another is the circuit subsystem that is modeled by the Modified Nodal Analysis method to generate a circuit subsystem. The coupling between the EM and circuit subsystems is achieved through a lumped port. Due to the local properties of DGFETD operations, only small coupling matrix equation systems are involved. …
Integration Of Arbitrary Lumped Multiport Circuit Networks Into The Discontinuous Galerkin Time-Domain Analysis, Ping Li, Li Jun Jiang
Integration Of Arbitrary Lumped Multiport Circuit Networks Into The Discontinuous Galerkin Time-Domain Analysis, Ping Li, Li Jun Jiang
Electrical and Computer Engineering Faculty Research & Creative Works
A hybrid electromagnetic (EM) circuit simulator is proposed for incorporating multiport lumped circuit networks through their admittance matrices into the discontinuous Galerkin time-domain (DGTD) method. The admittance matrix in the Laplace domain can be derived analytically or obtained from network parameters such as -parameters in the frequency domain. To convert frequency-dependent -parameters into the admittance matrix in the Laplace domain, the vector-fitting technique is employed to facilitate the mapping process. The computational domain of interest is split into two subdomains. One is the EM part solved by the DGTD, and another is the circuit part modeled by the basic I-V …
Finite Element Modeling Of A Superconducting Fault Current Limiter, Lale Ergene, J. Keith Nelson, Raghunath Parthasarathi
Finite Element Modeling Of A Superconducting Fault Current Limiter, Lale Ergene, J. Keith Nelson, Raghunath Parthasarathi
Turkish Journal of Electrical Engineering and Computer Sciences
This paper summarizes the work done to show finite element modeling results on a high temperature superconductor fault current limiter (FCL). The paper also gives the small mock-up design of the matrix FCL and its finite element model (FEM). It also discusses the limitations of the FEM and explains how the results from the FEM compare with the experimental data derived for the configuration. A 3-dimensional FEM has been used because of the structure of the real geometry, which does not show any plane or axisymmetric features.
A Novel Motor Speed Calculation Method Using Square Wave Speed Sensor Signals Via Fast Fourier Transform, Hayri̇ Arabaci, Osman Bi̇lgi̇n
A Novel Motor Speed Calculation Method Using Square Wave Speed Sensor Signals Via Fast Fourier Transform, Hayri̇ Arabaci, Osman Bi̇lgi̇n
Turkish Journal of Electrical Engineering and Computer Sciences
This paper presents a novel motor speed measurement method and experimental results using the fast Fourier transform (FFT). Motor speed is obtained using the square wave output signal of a speed sensor. In the proposed method, the speed can be measured in a wide range, and transient speed changes can also be clearly observed. The experiments were conducted during start-up and in steady state. The sampled speed data were transformed to frequency spectrums using the FFT. The frequency, which corresponds to the maximum amplitude in the spectrum, was used to calculate the motor speed. The test results show that the …
Distribution System Operation And Planning In The Presence Of Distributed Generation Technology, Gavin W. Jones, Badrul H. Chowdhury
Distribution System Operation And Planning In The Presence Of Distributed Generation Technology, Gavin W. Jones, Badrul H. Chowdhury
Electrical and Computer Engineering Faculty Research & Creative Works
Distributed generation (DG) is becoming an increasingly attractive multi-faceted paradigm in the field of power distribution as economic and environmental factors drive new technologies to be more efficient and less polluting than their earlier counterparts. an attempt is made to examine and compare three types of DG: diesel generators, microturbines, and small wind turbines within the structure of a distribution system. the DG types are compared in both steady-state and transient operation to determine which type is suitable for a particular application. Steady-state operation is examined under heavy loading conditions and each DG type is compared on the basis of …
Dual Band Dual Polarized Antenna With High Efficiency For Base Transceiver Stations, F. H. Kashani, M. Shahpari, Hossein Ameri Mahabadi
Dual Band Dual Polarized Antenna With High Efficiency For Base Transceiver Stations, F. H. Kashani, M. Shahpari, Hossein Ameri Mahabadi
Hossein Ameri Mahabadi
In this paper new array element for use in dual band dual polarized antenna will be introduced that has high efficiency (more than 95%) and has high isolation in both 900MHz and 1800MHz bands. Also radiation pattern of this antenna is according to IEC recommendation.
On The Use Of Singular Perturbations To Neglect The Dynamic Saliency Of Synchronous Machines, Steven D. Pekarek, Michael T. Lemanski, Eric A. Walters
On The Use Of Singular Perturbations To Neglect The Dynamic Saliency Of Synchronous Machines, Steven D. Pekarek, Michael T. Lemanski, Eric A. Walters
Electrical and Computer Engineering Faculty Research & Creative Works
A common approximation used in the analysis of power systems is the neglect of the dynamic saliency in synchronous machines. In this paper, it is shown that eliminating the error associated with neglecting dynamic saliency can be accomplished with the addition of a singular perturbation(s) into the machine model. By considering the elimination of error in such a way, singular-perturbation-based model-order-reduction techniques are used to derive detailed- and reduced-order models of synchronous machines where dynamic saliency is eliminated with zero error and no added numerical cost.