scholarly journals Systematization of the Simulation Process of Transformer Inrush Current Using EMTP

2019 ◽  
Vol 9 (12) ◽  
pp. 2398 ◽  
Author(s):  
Hun-Chul Seo ◽  
Gi-Hyeon Gwon
Keyword(s):  
Computer Simulation ◽  
Computer Simulations ◽  
Electromagnetic Transients ◽  
Inrush Current ◽  
Large Magnitude ◽  
Test Report ◽  
Protection Relay ◽  
Simulation Process ◽  
System Operator ◽  
Simulation Results

An inrush current is generated when a transformer is energized. This current has a large magnitude and rich harmonics, thereby causing mal-operation of the protection relay. Therefore, the development of countermeasures against inrush current is necessary, and this study has been performed by computer simulations. However, it is difficult for a power system operator to perform a computer simulation as it is difficult to determine what data should be selected and entered. Therefore, this paper establishes the simulation process of transformer inrush current using the Electromagnetic Transients Program (EMTP). Two methods to simulate the transformer inrush current are described in detail. Based on the actual 154 kV transformer test report in Korea, the simulation results of the inrush current using the two methods are discussed.

Computer Simulation of an Synthetic Ultraviolet Absorbent in the Interface of DMB and DMF

2010 ◽  
Vol 146-147 ◽  
pp. 966-971
Author(s):  
Qi Hua Jiang ◽  
Hai Dong Zhang ◽  
Bin Xiang ◽  
Hai Yun He ◽  
Ping Deng
Keyword(s):  
Computer Simulation ◽  
Computer Simulations ◽  
Density Functional ◽  
Density Functional Method ◽  
Mean Field ◽  
Functional Method ◽  
Dynamic Density ◽  
Interface Phase ◽  
Simulation Results

This work studies the aggregation of an synthetic ultraviolet absorbent, named 2-hydroxy-4-perfluoroheptanoate-benzophenone (HPFHBP), in the interface between two solvents which can not completely dissolve each other. The aggregation is studied by computer simulations based on a dynamic density functional method and mean-field interactions, which are implemented in the MesoDyn module and Blend module of Material Studios. The simulation results show that the synthetic ultraviolet absorbent diffuse to the interface phase and the concentration in the interface phase is greater than it in the solvents phase.

scholarly journals Quaternary regenerative CMOS logic circuits with high-impedance output state

2005 ◽  
Vol 18 (3) ◽  
pp. 505-514
Author(s):  
Dusanka Bundalo ◽  
Branimir Ðordjevic ◽  
Zlatko Bundalo
Keyword(s):  
Computer Simulation ◽  
Computer Simulations ◽  
Delay Time ◽  
Propagation Delay ◽  
Logic Circuits ◽  
Output State ◽  
High Impedance ◽  
Multiple Valued Logic ◽  
Propagation Delay Time ◽  
Simulation Results

Principles and possibilities of synthesis and design of quaternary multiple valued regenerative CMOS logic circuits with high-impedance output state are de- scribed and proposed in the paper. Two principles of synthesis and implementation of CMOS regenerative quaternary multiple-valued logic circuits with high-impedance output state are proposed and described: the simple circuits with smaller number of transistors, and the buffer/driver circuits with decreased propagation delay time. The schemes of such logic circuits are given and analyzed by computer simulations. Some of computer simulation results confirming descriptions and conclusions are also given in the paper.

scholarly journals New Protection Scheme Based on Coordination with Tie Switch in an Open-Loop Microgrid

Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4756
Author(s):  
Hun-Chul Seo
Keyword(s):  
Wavelet Transform ◽  
Power Supply ◽  
Fault Location ◽  
Current Flow ◽  
Open Loop ◽  
Electromagnetic Transients ◽  
Protection Relay ◽  
Protection Scheme ◽  
Small Loop ◽  
Simulation Results

Owing to the increase in renewable energy, microgrids (MGs) are increasing. A MG has a small loop-type grid configuration. In the loop MG, challenges in protection such as maloperation of protection relay may occur owing to bidirectional current flow. Herein, we propose a new protection scheme in the loop MG. Considerations for protection in loop MG and fault characteristics are analyzed. Based on these, a new index to solve the considerations for MG protection are proposed using a wavelet transform. Furthermore, the new protection scheme based on the coordination with tie switch using the proposed new index is proposed. To verify the proposed scheme, the MG and the proposed scheme are modeled using the electromagnetic transients program and MATLAB. Various simulations according to the fault location and the success/failure of fault section separation are performed. Simulation results indicate that the power supply on the original feeder can be maintained by proposed method.

scholarly journals Simulation and manufacturing of modified circular monopole microstrip antenna for UWB applications

2021 ◽  
Vol 10 (1) ◽  
pp. 70
Author(s):  
Bilal S. Taha ◽  
Hamzah M. Marhoon
Keyword(s):  
Computer Simulation ◽  
Microstrip Antenna ◽  
High Speed ◽  
Reasonable Agreement ◽  
Ultra Wideband ◽  
Simulation Process ◽  
High Speed Data ◽  
Simulation Results ◽  
Compact Design ◽  
Uwb Applications

Ultra-wideband (UWB) technology is one of the most promising wireless communication solutions to be developed quickly because of the high-speed data, wide bandwidth and excellent immunity to multipath interference. In this work, the compact design of a modified circular monopole microstrip antenna is simulated and manufactured for the UWB applications. The simulation process of the proposed antenna was done based on the finite integration of the Computer Simulation Technology (CST) Microwave Studio (MWS). The proposed antenna comprises a copper radiating patch, Roger’s Kappa-438 substrate, and a single stub act as a reflector. The simulation results showed a reasonable agreement with the results of the measurement and good performance was achieved in the range from 1.8 to 10 GHz with VSWR less than 2.0.

The Consulting Teacher Simulation Program

1983 ◽  
Vol 6 (2) ◽  
pp. 41-49 ◽  
Author(s):  
Sandra R. Lloyd
Keyword(s):  
Computer Simulation ◽  
Computer Simulations ◽  
Special Educators ◽  
Simulation Program ◽  
Regular Educators ◽  
Before And After ◽  
Simulation Results

With recent changes in the philosophy regarding placement of handicapped students, special educators are now often asked to serve as consultants to regular educators. A computer simulation was designed to expose special educators to some of the situations they may encounter in this new role. First, a Master Test was developed describing 30 typical consulting situations. Next, “correct” choices on this test were validated by experienced graduates of four university consulting teacher programs. Then the twenty situations on which there was a consensus of opinion were expanded into computer simulations of the problems, in which the participant was shown the likely consequences of each choice and asked to make further decisions to solve the problem. The Mastery Test was given to 19 special educators before and after they completed the simulation. Results indicated that the simulation enabled subjects to choose strategies significantly more like those of expert consulting teachers.

scholarly journals Multiple-valued regenerative CMOS logic circuits with high-impedance output state

2006 ◽  
Vol 19 (1) ◽  
pp. 39-46
Author(s):  
Dusanka Bundalo ◽  
Branimir Djordjevic ◽  
Zlatko Bundalo
Keyword(s):  
Computer Simulation ◽  
Computer Simulations ◽  
Logic Circuits ◽  
Output State ◽  
High Impedance ◽  
Multiple Valued Logic ◽  
Simulation Results

Principles and possibilities of synthesis and design of multiple-valued (MV) regenerative CMOS logic circuits with high-impedance output state and any logic basis are proposed and described in the paper. Two principles of synthesis and implementation of CMOS regenerative multiple-valued logic circuits with high-impedance output state are proposed and described: the simple circuits and the buffer/driver circuits. The schemes of such circuits are given and analyzed by computer simulations. Some of computer simulation results confirming descriptions and conclusions are also given in the paper.

SIMULATION OF SOFT START OF SYNCHRONOUS ELECTRIC DRIVES

2019 ◽  
Author(s):  
Shakhboz Dadabaev
Keyword(s):  
Computer Simulation ◽  
Electric Drive ◽  
Water Supply Systems ◽  
Factors Affecting ◽  
Electric Drives ◽  
Soft Start ◽  
Simulation Results ◽  
Pumping Units ◽  
Negative Factors ◽  
Supply Systems

The main negative factors affecting the starting modes of synchronous electric drives of pumping units of irrigation water supply systems were identified, computer simulation of direct and soft start of synchronous electric drive was made, the simulation results are shown in graphs and a brief conclusion was made on the study.

Computer simulation to evaluate the economics of landfill gas recovery

1998 ◽  
Vol 38 (2) ◽  
pp. 201-208
Author(s):  
M. W. Milke
Keyword(s):  
Computer Simulation ◽  
Computer Program ◽  
Landfill Gas ◽  
Base Case ◽  
Simulation Tool ◽  
Hypothetical Case ◽  
Gas Recovery ◽  
Fixed Set ◽  
Key Variables ◽  
Simulation Results

A need exists for tools to improve evaluations of the economics of landfill gas recovery. A computer simulation tool is presented. It uses a spreadsheet computer program to calculate the economics for a fixed set of inputs, and a simulation program to consider variations in the inputs. The method calculates the methane generated each year, and estimates the costs and incomes associated with the recovery and sale of the gas. Base case results are presented for a city of 500,000. An uncertainty analysis for a hypothetical case is presented. The simulation results can help an analyst see the key variables affecting the economics of a project.

A Computer Simulation Approach for Engineering Air-Jet Spun Yarns

1997 ◽  
Vol 67 (3) ◽  
pp. 223-230 ◽  
Author(s):  
Rangaswamy Rajamanickam ◽  
Steven M. Hansen ◽  
Sundaresan Jayaraman
Keyword(s):  
Computer Simulation ◽  
Computer Simulations ◽  
Fiber Length ◽  
Experimental Investigations ◽  
Simulation Approach ◽  
Air Jet ◽  
Fiber Fineness ◽  
Spun Yarns ◽  
Yarn Count ◽  
Wrap Angle

A computer simulation approach for engineering air-jet spun yarns is proposed, and the advantages of computer simulations over experimental investigations and stand-alone mathematical models are discussed. Interactions of the following factors in air-jet spun yarns are analyzed using computer simulations: yarn count and fiber fineness, fiber tenacity and fiber friction, fiber length and fiber friction, and number of wrapper fibers and wrap angle. Based on the results of these simulations, yarn engineering approaches to optimize strength are suggested.

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