Evaluating and derating of three-phase distribution transformer under unbalanced voltage and unbalance load using finite element method

Njafi, Atabak; İskender, İres; Genç, Naci

doi:10.1109/peoco.2014.6814418

Cited by 29 publications

(12 citation statements)

References 6 publications

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“…A three‐phase, Dyn11, 10/0.4‐kV, 1000‐kVA distribution transformer is studied in this paper. Three‐dimensional FEM solves the following poisson in order to determine the magnetic flux distribution :

\frac{\partial}{\partial x} ((), R \frac{\partial A}{\partial x}) + \frac{\partial}{\partial y} ((), R \frac{\partial A}{\partial y}) + \frac{\partial}{\partial z} ((), R \frac{\partial A}{\partial z}) = \frac{- n i}{S_{c}}

where R is the core sheet reluctivity, n is the number of winding turns, and S c is the cross section of the conductors. If we have a static analysis, the magnetizing current in Equation is known.…”

Section: Distribution Transformer Analysis Using Finite Element Methodsmentioning

confidence: 99%

“…When current flows into the windings of the transformer, the governing equation of the magnetic field is as follows :

\nabla^{2} A - μ σ \frac{\partial A}{\partial t} + μ J_{0} = 0

where μ is the magnetic permeability, σ is the electrical conductivity, and J 0 is the applied current density.

\frac{\partial A}{\partial t} = j w A

…”

Section: Distribution Transformer Analysis Using Finite Element Methodsmentioning

confidence: 99%

“…A three-phase, Dyn11, 10/0.4-kV, 1000-kVA distribution transformer is studied in this paper. Three-dimensional FEM solves the following poisson in order to determine the magnetic flux distribution [10]:…”

Section: Distribution Transformer Analysis Using Finite Element Methodsmentioning

confidence: 99%

“…Equation (2) displays the variations of magnetic vector potential A [11]. When current flows into the windings of the transformer, the governing equation of the magnetic field is as follows [10]:…”

Section: Distribution Transformer Analysis Using Finite Element Methodsmentioning

confidence: 99%

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A new approach to reduce the leakage flux and electromagnetic force on distribution transformer under unbalanced faults based on finite element method

Najafi

İskender

2015

Int. Trans. Electr. Energ. Syst.

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Summary The short‐cırcuıt capacity design of a transformer is one of the most significant and challenging criteria. Electromagnetic forces in transformer winding regions are produced by interaction between the leakage flux and current density. Under short circuit condition when currents increase to 20 times, windings are exposed to very high electromagnetic force. This paper is focused on the reduction of leakage flux and electromagnetic force under fault condition of distribution transformer. This article is composed of two parts. First, Finite Element Methods (FEM) that improved in Ansoft‐Maxwell has been used to investigate the leakage flux and electromagnetic forces of three‐phase, three leg, 10/0.4‐kV, 1000‐kVA distribution transformer. Then, to optimal design of transformer under single phase to ground short circuit condition two auxiliary winding was chosen as an active shielding to reduce the radial and axial leakage flux. According to Lenz's law this windings produce a magnetic flux that is the apposite of the leakage flux from an iron‐core system. Results indicate that the proposed auxiliary winding remarkably decreased the leakage flux and electromagnetic force in the winding regions. It should be noted that the resultant of main flux is not affected by auxiliary winding. Copyright © 2015 John Wiley & Sons, Ltd.

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\frac{\partial}{\partial x} ((), R \frac{\partial A}{\partial x}) + \frac{\partial}{\partial y} ((), R \frac{\partial A}{\partial y}) + \frac{\partial}{\partial z} ((), R \frac{\partial A}{\partial z}) = \frac{- n i}{S_{c}}

Section: Distribution Transformer Analysis Using Finite Element Methodsmentioning

confidence: 99%

“…When current flows into the windings of the transformer, the governing equation of the magnetic field is as follows :

\nabla^{2} A - μ σ \frac{\partial A}{\partial t} + μ J_{0} = 0

where μ is the magnetic permeability, σ is the electrical conductivity, and J 0 is the applied current density.

\frac{\partial A}{\partial t} = j w A

…”

Section: Distribution Transformer Analysis Using Finite Element Methodsmentioning

confidence: 99%

Section: Distribution Transformer Analysis Using Finite Element Methodsmentioning

confidence: 99%

Section: Distribution Transformer Analysis Using Finite Element Methodsmentioning

confidence: 99%

See 2 more Smart Citations

A new approach to reduce the leakage flux and electromagnetic force on distribution transformer under unbalanced faults based on finite element method

Najafi

İskender

2015

Int. Trans. Electr. Energ. Syst.

Self Cite

View full text Add to dashboard Cite

show abstract

“…2) Unbalance-induced energy losses Another main consequence from phase unbalance is additional energy losses, including the additional loss on the phases and that in the neutral and ground (if the neutral is earthed). The additional energy losses occur on both transformers [37], [38] and feeders [39], [40]. J Watson et al presented a method for the optimal dispatch of energy storage to minimize power losses on both the phases and the neutral [41].…”

Section: Consequences Of Phase Unbalancementioning

confidence: 99%

Review of Distribution Network Phase Unbalance: Scale, Causes, Consequences, Solutions, and Future Research Direction

Ma¹,

Fang²,

Kong³

2020

Preprint

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Phase unbalance is widespread in the distribution networks in the UK, continental Europe, US, China, and other countries. First, this paper reviews the mass scale of phase unbalance and its causes and consequences. Three challenges arise from phase rebalancing: the scalability, data scarcity, and adaptability (towards changing unbalance over time) challenges. Solutions to address the challenges are: 1) using retrofit-able, maintenance-free, automatic solutions to overcome the scalability challenge; 2) using data analytics to overcome the data-scarcity challenge; and 3) using phase balancers or other online phase rebalancing solutions to overcome the adaptability challenge. This paper categorizes existing phase rebalancing solutions into three classes: 1) load/lateral re-phasing; 2) using phase balancers; 3) controlling energy storage, electric vehicles, distributed generation, and micro-grids for phase rebalancing. Their advantages and limitations are analyzed and ways to overcome the limitations are recommended. Finally, this paper suggests future research topics: 1) long-term forecast of phase unbalance; 2) whole-system analysis of the unbalance-induced costs; 3) phase unbalance diagnosis for data-scarce LV networks; 4) technocommercial solutions to exploit the flexibility from large threephase customers for phase balancing; 5) the optimal placement of phase balancers; 6) the transition from single-phase customers to three-phase customers.

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Operation Features Researching of Three-Phase Transformers Switched on to an Asymmetric Load

Grinkrug¹,

Novgorodov²,

Tkacheva³

2021

Current Problems and Ways of Industry Development: Equipment and Technologies

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Evaluating and derating of three-phase distribution transformer under unbalanced voltage and unbalance load using finite element method

Cited by 29 publications

References 6 publications

A new approach to reduce the leakage flux and electromagnetic force on distribution transformer under unbalanced faults based on finite element method

A new approach to reduce the leakage flux and electromagnetic force on distribution transformer under unbalanced faults based on finite element method

Review of Distribution Network Phase Unbalance: Scale, Causes, Consequences, Solutions, and Future Research Direction

Operation Features Researching of Three-Phase Transformers Switched on to an Asymmetric Load

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