scholarly journals Core Stress Analysis of Amorphous Alloy Transformer for Rail Transit under Different Working Conditions

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 164
Author(s):  
Jianwei Shao ◽  
Cuidong Xu ◽  
Ka Wai Eric Cheng
Keyword(s):  
Amorphous Alloy ◽  
Working Conditions ◽  
Short Circuit ◽  
Element Model ◽  
Operating Conditions ◽  
Iron Core ◽  
Rail Transit ◽  
Transit System ◽  
The Core ◽  
Distribution Transformers

The rail transit system is a large electric vehicle system that is strongly dependent on the energy technologies of the power system. The use of new energy-saving amorphous alloy transformers can not only reduce the loss of rail transit power, but also help alleviate the power shortage situation and electromagnetic emissions. The application of the transformer in the field of rail transit is limited by the problem that amorphous alloy is prone to debris. this paper studied the stress conditions of amorphous alloy transformer cores under different working conditions and determined that the location where the core is prone to fragmentation, which is the key problem of smoothly integrating amorphous alloy distribution transformers on rail transit power supply systems. In this study, we investigate the changes in the electromagnetic field and stress of the amorphous alloy transformer core under different operating conditions. The finite element model of an amorphous alloy transformer is established and verified. The simulation results of the magnetic field and stress of the core under different working conditions are given. The no-load current and no-load loss are simulated and compared with the actual experimental data to verify practicability of amorphous alloy transformers. The biggest influence on the iron core is the overload state and the maximum value is higher than the core stress during short circuit. The core strain caused by the side-phase short circuit is larger than the middle-phase short circuit.

scholarly journals Mathematical modeling and harmonic analysis of SISFCL

2017 ◽  
Vol 36 (1) ◽  
pp. 258-270
Author(s):  
Debraj Sarkar ◽  
Debabrata Roy ◽  
Amalendu Bikash Choudhury ◽  
Sotoshi Yamada
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Harmonic Analysis ◽  
Voltage Drop ◽  
Element Model ◽  
Iron Core ◽  
Content Type ◽  
Hysteresis Characteristic ◽  
The Core ◽  
The Mathematical Model

Purpose A saturated iron core superconducting fault current limiter (SISFCL) has an important role to play in the present-day power system, providing effective protection against electrical faults and thus ensuring an uninterrupted supply of electricity to the consumers. Previous mathematical models developed to describe the SISFCL use a simple flux density-magnetic field intensity curve representing the ferromagnetic core. As the magnetic state of the core affects the efficient working of the device, this paper aims to present a novel approach in the mathematical modeling of the device with the inclusion of hysteresis. Design/methodology/approach The Jiles–Atherton’s hysteresis model is utilized to develop the mathematical model of the limiter. The model is numerically solved using MATLAB. To support the validity of model, finite element model (FEM) with similar specifications was simulated. Findings Response of the limiter based on the developed mathematical model is in close agreement with the FEM simulations. To illustrate the effect of the hysteresis, the responses are compared by using three different hysteresis characteristics. Harmonic analysis is performed and comparison is carried out utilizing fast Fourier transform and continuous wavelet transform. It is observed that the core with narrower hysteresis characteristic not only produces a better current suppression but also creates a higher voltage drop across the DC source. It also injects more harmonics in the system under fault condition. Originality/value Inclusion of hysteresis in the mathematical model presents a more realistic approach in the transient analysis of the device. The paper provides an essential insight into the effect of the core hysteresis characteristic on the device performance.

scholarly journals Study of Transformer Lifetime Due to Loading Process on 20 KV Distribution Line

2018 ◽  
Vol 2 (2) ◽  
pp. 25
Author(s):  
A.A.N. Amrita ◽  
W.G. Ariastina ◽  
I.B.G. Manuaba
Keyword(s):  
Residual Life ◽  
Power Transformer ◽  
Short Circuit ◽  
Life Time ◽  
Electric Power System ◽  
Transformer Oil ◽  
Maximum Efficiency ◽  
Iron Core ◽  
Distribution Transformers ◽  
Work Area

Power transformer is very important in electric power system due to its function to raise or lower the voltage according to its designation. On the power side, the power transformer serves to raise voltage to be transmitted to the transmission line. On the transmission side, the power transformer serves to distribute the voltage between the main substations or down to the distribution voltage. On the distribution side, the stresses are channeled to large customers or lowered to serve small and medium customers. As the power transformer is so importance, it is necessary to protect against disturbance, as well as routine and periodic maintenance, so that the power transformer can operate in accordance with the planned time. Some factors that affect the duration of the power transformer is the ambient temperature, transformer oil temperature, and the pattern of load. Load that exceeds the maximum efficiency of the transformer which is 80% of its capacity will cause an increase in transformer oil temperature. Transformer oil, other than as a cooling medium also serves as an insulator. Increasing the temperature of transformer oil will affect its ability as an isolator that is to isolate the parts that are held in the transformer, such as iron core and the coils. If this is prolonged and not handled properly, it will lead to failure / breakdown of insulation resulting in short circuit between parts so that the power transformer will be damaged. PLN data indicates that the power transformer is still burdened exceeding maximum efficiency especially operating in the work area of PLN South Bali Area. The results of this study, on distribution transformers with different loads, in DS 137, DS 263 and DS 363, show that DS 363 transformer with loading above 80% has the shortest residual life time compared to DS 263 and DS 137 which loading less than 80%.

Miniature Circuit Breaker Electromagnetic Release Simulation and Analysis

2013 ◽  
Vol 392 ◽  
pp. 398-402
Author(s):  
Jun Fang Zhang ◽  
Yao Fang ◽  
Zhi Gang Li ◽  
Yan Yan Luo
Keyword(s):  
Electromagnetic Force ◽  
Short Circuit ◽  
Circuit Breaker ◽  
Three Dimensional ◽  
Short Circuit Current ◽  
Element Model ◽  
Field Analysis ◽  
Iron Core ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

With the three-dimensional field analysis software Ansoft, we establish three-dimensional finite element model of the electromagnetic release, obtain the electromagnetic release static characteristics of electromagnetic force by simulation, and analyze the relationship between the electromagnetic force, the short-circuit current and the air gap size. By Analyzing the dynamic characteristics of moving iron core, different short-circuit currents influence on the velocity and displacement of the moving iron core was gained.

Load and response quantification of direct fixation fastening systems for heavy rail transit infrastructure

2021 ◽  
pp. 095440972098703
Author(s):  
Arthur de O Lima ◽  
J Riley Edwards ◽  
Luis W Chavez Quiroz ◽  
Yu Qian ◽  
Marcus S Dersch
Keyword(s):  
Life Cycle Cost ◽  
Field Performance ◽  
Quantitative Information ◽  
Field Investigation ◽  
Operating Conditions ◽  
Rail Transit ◽  
Transit System ◽  
Track Geometry ◽  
Vertical Loading ◽  
Heavy Rail

Ballastless track (i.e. slab track) systems are used extensively in passenger rail applications for improved track stability, alignment control, vibration, and life cycle cost (LCC) benefits. These systems regularly rely on Direct Fixation (DF) fasteners to connect the rail to the structure. Field performance observations have indicated that even under similar track geometry and train operating conditions, the DF fasteners useful life varies widely. Meanwhile, a review of literature reveals that there is limited prior research to guide optimization of DF fastener designs for heavy rail transit. Therefore, researchers at the University of Illinois at Urbana-Champaign (UIUC) conducted a field investigation at three sites on a United States legacy heavy rail transit system to quantify wheel-rail interface loading demands and DF fastener response. Track response variance across similar track geometry was found. Wheel loads ranged between 2.7 to 18.2 kip (12.0 to 81.0 kN) and 0.9 to 12.4 kip (4.0 to 55.2 kN) for vertical and lateral loads, respectively. Lateral rail head displacements ranged between −0.05 to 0.16 inches (−1.27 to 4.06 mm) while dynamic lateral stiffness ranged from 42 to 62 kip/in. (7.3 to 10.8 kN/mm), indicating a low stiffness ratio for the DF fastener studied. Differences in behavior are attributed to dynamic vehicle-track interaction, the relationship between balanced and operating speeds, and differences in track gauge between sites. A comparison of vertical loading results with two additional heavy rail transit agencies shows Burr distributions that accurately represent the loading demands. Results from this study provide quantitative information that can be leveraged to improve heavy rail transit DF fastening system design and development of representative design validation testing protocols.

Developments in Traction Transformer

2012 ◽  
Author(s):  
Subhas Sarkar
Keyword(s):  
Short Circuit ◽  
Real Life ◽  
Voltage Regulation ◽  
Essential Elements ◽  
Circuit Testing ◽  
Transit System ◽  
Transit Systems ◽  
Distribution Transformers ◽  
Draft Standard ◽  
Ordinary Power

Mass transit systems are gaining increased attention and popularity in the country. With this increased activity, more and more lines are getting added under public transit systems in more and more cities. One of the essential elements in the transit system is the traction transformer which powers the trains. With the emphasis on reliability, there is also increased awareness of the energy efficiency required of the traction substation equipments and the transformer in particular. Traction transformers are not ordinary power or distribution transformers. They have to meet several special requirements, including parameters like voltage regulation, impedance, commutation, short circuit withstand, operation with rectifiers, harmonic losses, wide fluctuation of load currents depending on the cyclic nature, etc. The reliability criteria are stringent and the traction transformers have to be properly designed, manufactured and tested, including short circuit testing for validation. Use of modern design tools like electric and magnetic field mapping and estimation of forces and stresses are helpful in computing them accurately. With the extensive use of vacuum circuit breakers, the subject of interaction of transformers and breakers have come to the foreground. New standards (like IEEE C57.142) have come into existence, which recommend methods to mitigate such effects. The author of this paper and his team has successfully applied these techniques in real life situations to solve problems. Work is in the final stages for preparation of a standard specifically for Traction Power Rectifier Transformers for transit applications (IEEE draft standard 1653.1) under the IEEE Vehicle Standards Committee.

scholarly journals Configurations, Power Topologies and Applications of Hybrid Distribution Transformers

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1215
Author(s):  
Alvaro Carreno ◽  
Marcelo Perez ◽  
Carlos Baier ◽  
Alex Huang ◽  
Sanjay Rajendran ◽  
...  
Keyword(s):  
Distribution Systems ◽  
Power Converter ◽  
Operating Conditions ◽  
Distribution Transformer ◽  
Nonlinear Loads ◽  
Electric Vehicle Charging ◽  
Distribution Transformers ◽  
Alternative Systems ◽  
Charging Stations ◽  
Hybrid Distribution

Distribution systems are under constant stress due to their highly variable operating conditions, which jeopardize distribution transformers and lines, degrading the end-user service. Due to transformer regulation, variable loads can generate voltage profiles out of the acceptable bands recommended by grid codes, affecting the quality of service. At the same time, nonlinear loads, such as diode bridge rectifiers without power factor correction systems, generate nonlinear currents that affect the distribution transformer operation, reducing its lifetime. Variable loads can be commonly found at domiciliary levels due to the random operation of home appliances, but recently also due to electric vehicle charging stations, where the distribution transformer can cyclically vary between no-load, rated and overrated load. Thus, the distribution transformer can not safely operate under highly-dynamic and stressful conditions, requiring the support of alternative systems. Among the existing solutions, hybrid transformers, which are composed of a conventional transformer and a power converter, are an interesting alternative to cope with several power quality problems. This article is a review of the available literature about hybrid distribution transformers.

scholarly journals Research on operating conditions of electric propulsion ships under transformer interturn short circuit

2021 ◽  
Vol 1976 (1) ◽  
pp. 012041
Author(s):  
Bo Ma ◽  
Xixiu Wu ◽  
Wenyu Ma ◽  
Qichao Zhang ◽  
Bowen Hou ◽  
...  
Keyword(s):  
Electric Propulsion ◽  
Short Circuit ◽  
Operating Conditions
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