scholarly journals Impact of the Cooling Equipment on the Key Design Parameters of a Core–Form Power Transformer

2016 ◽  
Vol 67 (6) ◽  
pp. 399-406
Author(s):  
Tamás Orosz ◽  
Zoltán Ádám Tamus
Keyword(s):  
Power Transformer ◽  
Short Circuit ◽  
Design Parameters ◽  
Significant Difference ◽  
Previous Algorithm ◽  
Transformer Design ◽  
New Variables ◽  
The Cost ◽  
Mathematical Optimisation ◽  
The Impact

Abstract The first step in the transformer design process is to find the active part’s key design parameters. This is a non-linear mathematical optimisation task, which becomes more complex if the economic conditions are considered by the capitalisation of the losses. Geometric programming combined with the method of branch and bound can be an effective and accurate tool for this task even in the case of core-form power transformers, when formulating the short-circuit impedance in the required form is problematic. Most of the preliminary design methods consider only the active part of the transformer and the capitalised costs in order to determine the optimal key design parameters. In this paper, an extension of this meta-heuristic transformer optimisation model, which takes the cost of the insulating oil and the cooling equipment into consideration, is presented. Moreover, the impact of the new variables on the optimal key design parameters of a transformer design is examined and compared with the previous algorithm in two different economic scenarios. Significant difference can be found between the optimal set of key-design parameters if these new factors are considered.

scholarly journals Non-linear Impact of the Short Circuit Impedance Selection on the Cost Optimized Power Transformer Design

2020 ◽  
Vol 64 (3) ◽  
pp. 221-228
Author(s):  
Tamás Orosz ◽  
Zoltán Ádám Tamus
Keyword(s):  
Design Process ◽  
Power Transformer ◽  
Short Circuit ◽  
Design Rule ◽  
Design Parameters ◽  
Electrical Machine ◽  
Preliminary Design ◽  
Large Power ◽  
Final Design ◽  
The Cost

Since the electrical machine design is a complex task it can be divided into sub-problems, e.g. preliminary and final design processes and checking of the final design. This paper deals with the preliminary design process, which provides the key-design parameters of the electrical machine. Traditionally, these electrical machine models in preliminary design phase neglect or use oversimplified insulation system models and the tap changing selection is not involved during the calculation of key-design parameters. The aim of this study is to assess the effect of the insulation distance minimization and tap-changing on the key design parameters of a cost-optimized large power transformer. For this purpose, the paper shows some examples, where the cost optimal design — in contrast to the classical insulation design rule — contains larger insulation distances than the possible minimum values. The effect of tap-changing methods are also investigated. These cost optimization made by a verified, metaheuristic method-based transformer optimization algorithm. The results show involving the insulation design and tap-changing selection into the preliminary design process can provide more economical designs.

scholarly journals Evolution and Modern Approaches of the Power Transformer Cost Optimization Methods

2019 ◽  
Vol 63 (1) ◽  
pp. 37-50 ◽  
Author(s):  
Tamás Orosz
Keyword(s):  
Optimization Problems ◽  
Power Transformer ◽  
Cost Optimization ◽  
Mathematical Optimization ◽  
Optimization Methods ◽  
Design Parameters ◽  
Preliminary Design ◽  
Transformer Design ◽  
Physical Fields ◽  
The Cost

Transformer design is a challenging engineering task, where the different physical fields have to be harmonized together to fulfill the implied specifications. Due to the difficulty of this task, it can be separated into several subproblems. The first subproblem, in the pre-concept phase, during the transformer design is the calculation of the cost optimal key-design parameters, where not only the technical but also the economical parameters have to be considered, as well. This subproblem belongs to the most general branch of the non-linear mathematical optimization problems. This paper presents the main directions of the evolution and trends in the power transformer design. Main directions of the considered research and the future trends in the field of preliminary design transformer optimization methods are summarized.

Analytical and Experimental Studies on Induced Current Switching by a Fault-Proof Gas Insulated Earthing Switch

2010 ◽  
Vol 11 (5) ◽  
Author(s):  
Mandava Mohana Rao ◽  
Moutusi Paul ◽  
H.S. Jain
Keyword(s):  
Short Circuit ◽  
Experimental Studies ◽  
Short Circuit Current ◽  
Design Parameters ◽  
Induced Current ◽  
Current Switching ◽  
Test Circuit ◽  
Reliable Performance ◽  
Gas Insulated Substation ◽  
The Impact

Fault-proof earthing switches are one of the important modules of a gas insulated substation, as it enables make at 100 percent short circuit current, which is functionally different from maintenance earthing switches. The fault-proof earthing switch shall be designed to make and break electro-magnetically and electro-statically induced currents as per IEC-62271-102. The paper discusses the impact of “test circuit configurations and voltage” on test parameters for gas insulated fault-proof earthing switch utilizing simulation with PSCAD software. Authors record the development of a 145 kV gas insulated fault proof earthing switch by considering novel design features like minimum arcing/pre-arcing time, effective current transfer from arcing contact to ground terminal, etc. The development has been evaluated successfully for electro-magnetically and electro-statically induced current duties as per IEC. Finally, design parameters to be considered for ensuring reliable performance during induced current switching from fault-proof earthing switches are also discussed.

Impact of Advancing Technology on Nuclear Facility Operation

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Jonathan K. Corrado ◽  
Ronald M. Sega
Keyword(s):  
Human Error ◽  
New Technologies ◽  
Nuclear Industry ◽  
Nuclear Facilities ◽  
Event Scale ◽  
Technological Advances ◽  
Significant Difference ◽  
The Cost ◽  
The Impact ◽  
The U.S

Abstract Many unfortunate and unintended adverse industrial incidents occur across the U.S. each year, and the nuclear industry is no exception. Depending on the severity, these incidents can be problematic for people, the facilities, and surrounding environments. These incidents occur for a number of varying reasons, but more often than not, human error is an accomplice. This article explores whether the complexity and changing technologies, which affect the way operators interact within the systems of the nuclear facilities, exacerbate the severity of incidents caused by human error. A review of nuclear incidents in the U.S. from 1955 to 2010 reaching level three or higher on the International Nuclear Event Scale (INES) scale was conducted. The cost of each incident at facilities that had recently undergone technological changes affecting plant operator's jobs was compared to those facilities which had not undergone changes. A t-test was applied and determined a statistically significant difference between the two groups. This affirmed that technological advances at nuclear facilities that affect how operators interact within the plant system increase the severity of resulting incidents. Next, a follow-on study was conducted to determine the impact from the incorporation of new technologies into nuclear facilities. The data indicated that spending more money on upgrades increased the capacity of the facility as well as the number of incidents reported, but the incident severity was minor.

Cost of Pavement Damage Due to Heavier Loads on Louisiana Highways: Preliminary Assessment

2000 ◽  
Vol 1732 (1) ◽  
pp. 3-11 ◽  
Author(s):  
Freddy L. Roberts ◽  
Ludfi Djakfar
Keyword(s):  
Pavement Design ◽  
Design Parameters ◽  
Preliminary Assessment ◽  
Design Data ◽  
Present Worth ◽  
Gross Vehicle Weight ◽  
Pavement Damage ◽  
The Cost ◽  
Government Statistics ◽  
The Impact

A preliminary assessment is made of the impact of increasing the gross vehicle weight (GVW) from current legal limits to 100,000 lb (45 400 kg) on vehicles hauling sugarcane, rice, timber, and cotton. Sections of road were chosen in each area of Louisiana where commodities are produced, the amount of each commodity hauled was estimated, and the effects of increasing the GVW were evaluated for each section using pavement design models. Design data were secured from the Louisiana Department of Transportation and Development computer database and project files to determine the pavement design parameters and traffic estimates for each road. The number of vehicles hauling the 1998 harvest payload was estimated, a projected increase in the production of each commodity was estimated on the basis of government statistics, and rehabilitations were designed with the use of the 1986 AASHTO Design Guide for a 20-year analysis period. Present worth (PW) was calculated for each GVW scenario for each roadway. Comparisons of PW between the weight scenarios showed that increases in GVW have more effect on state and U.S. highways than they do on Interstate highways. Any increase in GVW over current limits increases the cost of overlays and decreases the length of time before an overlay is required. The cost increase due to increasing the GVW is substantial. Fee structures should be modified by the legislature so that these costs are paid for either through the current registration and overweight permit fee structure or through some new tax, such as a ton-mile tax.

An Innovative Solution for Type Testing of Power Transformers

2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Manohar Singh ◽  
Vishnuvarddhan Telukanta ◽  
K S Meera
Keyword(s):  
Power Transformer ◽  
Short Circuit ◽  
Operating Conditions ◽  
Power Transformers ◽  
Test Facility ◽  
Online Testing ◽  
Testing Laboratory ◽  
Power Testing ◽  
Grid Operation ◽  
The Impact

Abstract Type tests are essential to assess the short circuit withstand capabilities of transformer windings. The mechanical durability of power equipment are checked against the mechanical forces developed during making/breaking short circuit operations. These type tests are generally carried out in indoor transformer test laboratories. Testing of Power Transformer for size more than 200 MVA in 765/400 kV voltage class in an indoor laboratory is not economically feasible. Now a days, power transformer manufacturers are fabricating single phase auto- power transformers of size up to 630 megawatt volt ampere (MVA) rating. Type testing of these transformers in indoor laboratories is not feasible. In view of this, strong short circuit fault feeding capabilities of the national grids can be utilized for type testing of these power transformers in an online manner. However, this may affect the grid operation/control during weak grid operating conditions. Recently, National High Power Testing Laboratory is established for testing of power transformer upto of 630 MVA. This is a unique online transformer test facility for testing of 765/400/220/132 kV class power transformers. An offline simulation has been carried out in this article, to assess the impact of online type testing on the Indian National grid. In this article, an online testing scheme has been presented which enables the national grid operator to analysis the prevailing grid condition & subsequently to decide the safe rating of the power transformer for online testing. The simulated results are cross checked with field results and it is found that simulated results are close to actual field results. The concurrence of simulated and field results helped in successfully commissioning of the testing laboratory.

Simulation of Power Transformer Windings Displacement Caused by Multiple Short-Circuit Forces

2012 ◽  
Vol 268-270 ◽  
pp. 1341-1344
Author(s):  
Hong Kui Li
Keyword(s):  
Power Transformer ◽  
Short Circuit ◽  
Deformation Analysis ◽  
Theoretical Formula ◽  
Cumulative Impact ◽  
Elastic Plastic ◽  
Transformer Winding ◽  
Short Circuits ◽  
The Stability ◽  
The Impact

This research studies the displacement on the windings of transformer due to multiple short-circuit forces. The power transformer winding deformations cumulative impact of multiple short-circuits are studied. the cumulative impact of multiple short-circuit deformation of laminated cylindrical shell with stiffeners model is established, the impact of accumulated deformation of multiple short-circuit of transformer winding is calculated with large deformation elastic-plastic theory , the text introduced by the theoretical formula for power transformer windings of the elastic-plastic deformation analysis of and winding to determine the stability have great significance, To verify the computation results, they are compared with those obtained using ANSYS software simulation.

scholarly journals Allocation of 0.4 kV PTL Sectionalizing Units under Criteria of Sensitivity Limits and Power Supply Reliability

2021 ◽  
Vol 11 (24) ◽  
pp. 11608
Author(s):  
Alina Vinogradova ◽  
Alexander Vinogradov ◽  
Vadim Bolshev ◽  
Andrey Izmailov ◽  
Alexey Dorokhov ◽  
...  
Keyword(s):  
Transmission Lines ◽  
Power Supply ◽  
Power Transmission ◽  
Short Circuit ◽  
Reducing Power ◽  
Power Transmission Lines ◽  
Electrical Networks ◽  
The Cost ◽  
The Impact ◽  
Supply Reliability

Sectionalizing 0.4 kV power transmission lines (PTL) improves power supply reliability and reduces electricity undersupply through the prevention of energy disconnection of consumers in the event of a short circuit in the power line behind the sectionalizing unit (SU). This research examines the impact of sectionalizing on power supply reliability and reviews the literature on sectionalizing unit allocation strategies in electrical networks. This paper describes the experience of the use of sectionalizing units with listing strengths and weaknesses of adopted technical solutions and describes the new structure of sectionalizing units. A new methodology is proposed, whereby there are two criteria for allocating SU in 0.4 kV power transmission lines. The first criterion is the sensitivity limits against single-phase short circuits used for calculating the maximum distance at which SU can be installed. The second criterion is power supply reliability improvement, evaluating the cost-effectiveness of installing sectionalizing equipment by reducing power supply outage time. The established methodology was put to the test on an actual electrical system (Mezenka village, Orel area, Russia), which demonstrated that the installation of a sectionalizing unit paid off.

scholarly journals Investigation of The DGs Effect on The Coordination Between Protective Elements in Distribution Network

2019 ◽  
Vol 7 (4) ◽  
pp. 227-237
Author(s):  
Abdallah Reda ◽  
Prof. M.Farahat ◽  
Prof. Amal F.Abdelgawad ◽  
Associate Prof. A.T.M Taha
Keyword(s):  
Distribution System ◽  
Power Flow ◽  
Power Transformer ◽  
Short Circuit ◽  
Distribution Network ◽  
Voltage Profile ◽  
Electric Network ◽  
Protective Devices ◽  
Additional Costs ◽  
The Impact

Addition of Distributed Generators (DGs) to the electric network have more advantages to the network. It improves the voltage profile and the power flow in the network. In the last decade, DGs is used in power system, especially the distribution system. Coordination study for protective devices must be performed on the distribution network with DGs to reach selectivity with minimum clearance time of fault. Due to DG insertion to the electric system, the short circuit level is changed and coordination between protective elements should be done. This paper presents a technique to avoid the miscoordination problem between protective devices due to the impact of DG units insertion without any additional costs. The proposed technique depend on activating and updating the setting of network relays to achieve correct coordination. Also, it doesn't need any additional costs or any additional equipement to be installed in the electric network. This paper make studies on a real radial system of power transformer with its feeders of a 66kV utility substation before and after adding DGs. ETAP software is used to simulate the network under study.

scholarly journals Open access journals are as likely to be referenced by the Orthopaedic literature, despite having a lower impact factor than subscription-based journals

SICOT-J ◽  
2021 ◽  
Vol 7 ◽  
pp. 64
Author(s):  
Robert Cooke ◽  
Neil Jain
Keyword(s):  
Open Access ◽  
Impact Factor ◽  
Open Access Journal ◽  
Open Access Journals ◽  
Significant Difference ◽  
Orthopaedic Literature ◽  
Top 40 ◽  
The Cost ◽  
Number Of Citations ◽  
The Impact

Background: The internet has changed the way we access and publish Orthopaedic literature. Traditional subscription journals have been challenged by the open access method of publication which permits the author to make their article available to all readers for free, often at a cost to the author. This has also been adopted in part by traditional subscription journals forming hybrid journals. One of the criticisms of open access publications is that it provides the author with a “pay to publish” opportunity. We aimed to determine if access to the journals impacts their influence. Methods: We selected the top 40 Trauma and Orthopaedic Journals as ranked by the SCImago Rank. Each journal was reviewed and assessed for the journal quality, defined by reviewing the journal impact factor and SCImago rank; influence, defined by reviewing the top 10 articles provided by the journal for the number of citations; and cost of open access publication. Results: Of the top 40 journals, 10 were subscription, 10 were open access, and 20 were hybrid journals. Subscription journals had the highest mean impact factor, and SCImago rank with a significant difference in the impact factor (p = 0.001) and SCImago rank (p = 0.021) observed between subscription and open access journals. No significant difference was seen between citation numbers of articles published in subscription and open access journals (p = 0.168). There was a positive correlation between the cost of publishing in an open access journal and the impact factor (r = 0.404) but a negative correlation between cost and the number of citations (r = 0.319). Conclusion: Open access journals have significantly lower quality measures in comparison to subscription journals. Despite this, we found no difference between the number of citations, suggestive of there being no difference in the influence of these journals in spite of the observed difference in quality.

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