scholarly journals Improve the Three-phase Unbalance Rate of Railway System Under 2% By Three Kinds of Special Transformer Wiring

2021 ◽  
Author(s):  
Chien-Hsu Chen ◽  
Chin E. Lin
Keyword(s):  
Service Life ◽  
Load Capacity ◽  
Railway Vehicle ◽  
Voltage Unbalance ◽  
The Past ◽  
Three Phase ◽  
Railway System ◽  
Ieee Standard ◽  
Model Derivation ◽  
The Cost

Because imbalanced power will cause the loss of the propulsion motor of the railway vehicle, and the increase in temperature will shorten the service life of the electric vehicle. Not only this, but also increase the cost of electricity and maintenance. In the past, the industry only focused on methods to improve power quality such as load capacity, relay setting, and harmonic resolution. Now, the consider of three-phase unbalance rate (TPUR) must be applied. I propose special transformers wiring (STW) to improve the three unbalance rates and provide different transformer wiring methods. According to the IEEE Committee, in the future, power companies will need to install balanced relay stations to improve three-phase unbalance rate. the internal regulations of Taipower must be less than 4.5% (voltage unbalance rate (NPSUR)of 2.5% and motor temperature rise of 12.5%). the derivation of the transformer "three-phase unbalance rate" model is the focus of the railway system. This research is based on the model derivation of different wiring methods to improve the hot problem caused by the three-phase imbalance and improve the service life of the train. And pointed out that Scott, Le-Blanc, Modified-Woodbridge three wiring methods can be applied to future railway system routes to improve the three-phase unbalance rate, in line with the IEEE standard of less than 2%.

scholarly journals Improve the Three-Phase Unbalance Rate of Railway System Under 2% By Three Kinds of Special Transformer Wiring

2021 ◽  
Author(s):  
Hsu Chien Chen ◽  
Shir Kuan Lin ◽  
Chin-E. Lin
Keyword(s):  
Service Life ◽  
Load Capacity ◽  
Railway Vehicle ◽  
Voltage Unbalance ◽  
The Past ◽  
Three Phase ◽  
Railway System ◽  
Ieee Standard ◽  
Model Derivation ◽  
The Cost

Because imbalanced power will cause the loss of the propulsion motor of the railway vehicle, and the increase in temperature will shorten the service life of the electric vehicle. Not only this, but also increase the cost of electricity and maintenance. In the past, the industry only focused on methods to improve power quality such as load capacity, relay setting, and harmonic resolution. Now, the consider of three-phase unbalance rate (TPUR) must be applied. I propose special transformers wiring (STW) to improve the three unbalance rates and provide different transformer wiring methods. According to the IEEE Committee, in the future, power companies will need to install balanced relay stations to improve three-phase unbalance rate. the internal regulations of Taipower must be less than 4.5% (voltage unbalance rate (NPSUR)of 2.5% and motor temperature rise of 12.5%). the derivation of the transformer "three-phase unbalance rate" model is the focus of the railway system. This research is based on the model derivation of different wiring methods to improve the hot problem caused by the three-phase imbalance and improve the service life of the train. And pointed out that Scott, Le-Blanc, Modified-Woodbridge three wiring methods can be applied to future railway system routes to improve the three-phase unbalance rate, in line with the IEEE standard of less than 2%.

scholarly journals Voltage Unbalance, Power Factor and Losses Optimization in Electrified Railways Using an Electronic Balancer

Electricity ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 554-572
Author(s):  
António P. Martins ◽  
Pedro Rodrigues ◽  
Mahmoud Hassan ◽  
Vítor A. Morais
Keyword(s):  
Low Power ◽  
Power Factor ◽  
Electric Energy ◽  
Field Measurements ◽  
Electric Grid ◽  
Voltage Unbalance ◽  
Three Phase ◽  
Railway System ◽  
Regenerative Energy ◽  
Electrified Railways

Unbalanced currents, low power factor and high losses contribute to increasing the bill infrastructure managers must pay to the TSO/DSO operator that supplies electric energy to the railway system. Additionally, if regenerative energy coming from braking regimes is not allowed to be injected into the grid or even is penalized when it occurs, then the optimization of those parameters must be pursued. One of the possible measures that can be taken to counteract those phenomena is the installation of electronic balancers in heavy loaded substations in order to optimize the interface to the three-phase electric grid. This paper shows the benefit of such use taking examples from real conditions and realistic simulations assumed equivalent to field measurements.

Measuring the cost of environmental compliance for Waikato dairy farmers - a survey approach

2015 ◽  
Vol 77 ◽  
pp. 159-166
Author(s):  
T.O.R. Macdonald ◽  
J.S. Rowarth ◽  
F.G. Scrimgeour
Keyword(s):  
Qualitative Data ◽  
Management Practice ◽  
Dairy Farm ◽  
Environmental Compliance ◽  
Dairy Farmers ◽  
The Past ◽  
Farm Systems ◽  
The Cost ◽  
Farm System ◽  
Survey Approach

The link between dairy farm systems and cost of environmental compliance is not always clear. A survey of Waikato dairy farmers was conducted to establish the real (non-modelled) cost of compliance with environmental regulation in the region. Quantitative and qualitative data were gathered to improve understanding of compliance costs and implementation issues for a range of Waikato farm systems. The average oneoff capital cost of compliance determined through a survey approach was $1.02 per kg milksolids, $1490 per hectare and $403 per cow. Costs experienced by Waikato farmers have exceeded average economic farm surplus for the region in the past 5 years. As regulation increases there are efficiencies to be gained through implementing farm infrastructure and farm management practice to best match farm system intensity. Keywords: Dairy, compliance, farm systems, nitrogen, Waikato

Three-phase to Single-phase Matrix Converter for Improvement of Three-phase Voltage Unbalance in Distribution System

2015 ◽  
Vol 135 (3) ◽  
pp. 168-180 ◽  
Author(s):  
Ryota Mizutani ◽  
Hirotaka Koizumi ◽  
Kentaro Hirose ◽  
Kazunari Ishibashi
Keyword(s):  
Distribution System ◽  
Single Phase ◽  
Matrix Converter ◽  
Phase Voltage ◽  
Voltage Unbalance ◽  
Three Phase

Advance Protection for Three Phase Induction Motor using Microcontroller Atmega32

2018 ◽  
Vol 8 (1) ◽  
pp. 172
Author(s):  
Karan S Belsare ◽  
Gajanan D Patil
Keyword(s):  
Induction Motor ◽  
Low Cost ◽  
Short Circuit ◽  
Cost Factor ◽  
Protection Scheme ◽  
Three Phase ◽  
The Cost

A low cost and reliable protection scheme has been designed for a three phase induction motor against unbalance voltages, under voltage, over voltage, short circuit and overheating protection. Taking the cost factor into consideration the design has been proposed using microcontroller Atmega32, MOSFETs, relays, small CTs and PTs. However the sensitivity of the protection scheme has been not compromised. The design has been tested online in the laboratory for small motors and the same can be implemented for larger motors by replacing the i-v converters and relays of suitable ratings.

Attraction of prey

2018 ◽  
Author(s):  
John D. Horner ◽  
Bartosz J. Płachno ◽  
Ulrike Bauer ◽  
Bruno Di Giusto
Keyword(s):  
Visual Cues ◽  
Synergistic Action ◽  
Carnivorous Plants ◽  
Future Research ◽  
Acoustic Cues ◽  
Qualitative And Quantitative Analysis ◽  
Qualitative And Quantitative ◽  
The Past ◽  
The Cost ◽  
Prey Attraction

The ability to attract prey has long been considered a universal trait of carnivorous plants. We review studies from the past 25 years that have investigated the mechanisms by which carnivorous plants attract prey to their traps. Potential attractants include nectar, visual, olfactory, and acoustic cues. Each of these has been well documented to be effective in various species, but prey attraction is not ubiquitous among carnivorous plants. Directions for future research, especially in native habitats in the field, include: the qualitative and quantitative analysis of visual cues, volatiles, and nectar; temporal changes in attractants; synergistic action of combinations of attractants; the cost of attractants; and responses to putative attractants in electroantennograms and insect behavioral tests.

Design of Electrolytic Strengthening Machine for Cutting Edge of Cutter

2016 ◽  
Vol 693 ◽  
pp. 1585-1590
Author(s):  
Yi Zhuo Guo ◽  
Xian Guo Yan ◽  
Shu Juan Li ◽  
Hong Guo
Keyword(s):  
Service Life ◽  
Calculation Method ◽  
High Speed ◽  
High Speed Steel ◽  
Cutting Edge ◽  
The Cost ◽  
Electric Quantity

Many studies have proved the service life of cutter can be prolonged by electrolytic strengthening. Based on the theory of electrolytic strengthening technology, this paper introduced and developed prototype equipment for strengthening cutting edge of rotary cutter and put forward a calculation method of total electric quantity consumption during the electrolysis suitable for microcontroller. The M8 high-speed steel tap is taken as a strengthening example. After finished the strengthening process that it clearly see the results of the surface of tap was obviously polished by observing the micrograph. This equipment improves the reliability of electrolytic strengthening and the cost is relatively cheap.

Are Apprenticeships Still Relevant in the 21st Century? A Case Study of Changing Youth Training Arrangements in German Banks

ILR Review ◽  
2002 ◽  
Vol 55 (4) ◽  
pp. 667-685 ◽  
Author(s):  
David Finegold ◽  
Karin Wagner
Keyword(s):  
21St Century ◽  
Cost Savings ◽  
New Firms ◽  
Workplace Flexibility ◽  
Transferable Skills ◽  
The Past ◽  
Detailed Case ◽  
The Cost ◽  
Youth Training

The authors present a detailed case study of the evolution of apprenticeships in German banking over the past two decades to analyze why employers continue to be willing to invest in these programs that provide workers with transferable skills. They explain employers' motivation in terms of two “logics.” Some considerations stemming from the logic of consequences, such as recruitment cost savings and enhanced workplace flexibility, encourage retention of the apprenticeship system. On balance, however, the cost calculus that is at the heart of the logic of consequences would, if unopposed, encourage head-hunting for apprentices trained by other firms, eventually undermining the system. The countervailing logic of appropriateness, however, discourages defections from the system by fostering trust among employers, encouraging new firms to participate in the system, supporting the strong reputational effect associated with training, and creating mechanisms with which banks can have a hand in keeping the system efficient.

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