Short-circuit stress calculation in oval windings

Meško, Nina; Ćućić, Branimir; Žarko, Damir

doi:10.1016/j.proeng.2017.09.720

Cited by 3 publications

(9 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Figure 3 shows an example of the buckling of the outer part of the LV foil winding (with 1 cooling duct), while the inner part is unaffected. Mean compressive radial stress (section 0) in the outermost part of the inner winding is higher than the mean compressive stress in the whole winding (by 60% in the case of one cooling duct in the foil winding [10]) due to the higher flux density. Furthermore, critical stress slightly decreases in the outer part of the LV winding.…”

Section: Force Calculationmentioning

confidence: 84%

“…For oval and unsupported winding critical stress can be calculated by using the expression (18) for the free buckling [10]. In this paper, the focus is on foil windings with epoxy coated layer insulation (diamond dotted press paper, DPP) which implies that the equivalent modulus of elasticity E equiv must be taken for the composite structure of the conductor material (aluminium) and epoxy coated layer insulation (as discussed later in section 0).…”

Section: The Proposed Methods For Determination Of the Critical Stressmentioning

confidence: 99%

“…In this paper, the focus is on foil windings with epoxy coated layer insulation (diamond dotted press paper, DPP) which implies that the equivalent modulus of elasticity E equiv must be taken for the composite structure of the conductor material (aluminium) and epoxy coated layer insulation (as discussed later in section 0). To avoid buckling of the winding, the following criterion must be fulfilled [10]:…”

Section: The Proposed Methods For Determination Of the Critical Stressmentioning

confidence: 99%

“…The CIGRE Working Group 12.19 [9] gives critical buckling stress for inner oval winding based on a "long column collapse" assuming the round part of oval winding to be unsupported. The paper [10] focusses on inner oval winding with the foil conductor giving an analytical approach for mechanical strength calculation. In [11] it can be found that the short-circuit design of rectangular windings is generally worked out empirically and that the real strength of the composite structure of a winding may depend almost entirely on the bond.…”

Section: Related Workmentioning

confidence: 99%

“…In [11] it can be found that the short-circuit design of rectangular windings is generally worked out empirically and that the real strength of the composite structure of a winding may depend almost entirely on the bond. This paper extends [10] by applying the principle given in [9]. The focus will be on determining the critical stress of inner foil winding with epoxy coated insulation using the equivalent Young's modulus of elasticity obtained experimentally from the deflection of 12 sample models loaded with bending force on a tensile test machine.…”

Section: Related Workmentioning

confidence: 99%

See 4 more Smart Citations

Critical stress of oval foil winding with epoxy coated insulation determined using measured equivalent modulus of elasticity

Meško¹,

Ćućić²,

Žarko

2020

Automatika

Self Cite

View full text Add to dashboard Cite

In the distribution transformers design oval windings are used due to economic advantages. On the other hand, such windings are more susceptible to radial forces in a short circuit. A diamond dotted paper with an epoxy coating is used in order to increase the stiffness of the winding. Despite that, winding failure may occur during the short circuit, e.g. buckling of inner winding. Because of a very thin foil conductor (typically 0.5-2 mm), the most critical is inner low voltage foil winding which can collapse due to radial forces at stresses far below the elastic limit of conductor material. This paper shows an analytical approach to the calculation of critical stress in inner oval foil winding with epoxy coated insulation. Critical stress was calculated using the equation for free buckling of round winding. Equivalent Young's modulus of elasticity was obtained experimentally from the testing of the sample model loaded with bending force on a tensile test machine. A total of 12 test samples were formed from aluminium foil conductor and diamond dotted paper and cured at the temperature of 105°C. The results were successfully verified on distribution transformers subjected to short circuit withstand tests.

show abstract

Section: Force Calculationmentioning

confidence: 84%

Section: The Proposed Methods For Determination Of the Critical Stressmentioning

confidence: 99%

Section: The Proposed Methods For Determination Of the Critical Stressmentioning

confidence: 99%

Section: Related Workmentioning

confidence: 99%

Section: Related Workmentioning

confidence: 99%

See 3 more Smart Citations

Critical stress of oval foil winding with epoxy coated insulation determined using measured equivalent modulus of elasticity

Meško¹,

Ćućić²,

Žarko

2020

Automatika

Self Cite

View full text Add to dashboard Cite

show abstract

Analysis of Three-Phase Short-Circuit Electrodynamic Variation Characteristics of Power Transformers

Wang,

Yuan

et al. 2023

2023 7th International Conference on Electrical, Mechanical and Computer Engineering (ICEMCE)

View full text Add to dashboard Cite

Finite-Element Calculation of Electromagnetic Forces in the Deferent Shapes of Distribution Transformers Winding Under Short Circuit Condition

Hussein

Hameed

2022

jeasd

View full text Add to dashboard Cite

This paper is concerned with calculating the electromagnetic forces in the windings of distribution transformers with different shapes of coils. The electromagnetic forces as well as the magnetic flux density and their distribution were analyzed and calculated using Finite Element Method (FEM). The Finite Element models of the distribution transformers with non-linear magnetic characteristics for the iron core are built using FEM software "ANSYS". In this paper, the static analysis method is based on two-dimensional models, and these models have been solved by using the formula for the magnetic vector voltage (A). Three types of three-phase distribution transformers were adopted, each with a capacity of 250 kVA and a voltage ratio is 11/0.416 kV. These types of transformers with different shapes of coils are stack core transformer with oval coil, wound core transformer with rectangular coil, and stack core transformer with cylindrical coil. The results obtained from the FEM analysis agreed with the design calculations which depend on the conventional design formulas. The most important contributions of this study are to building two-dimensional models for different types of distribution transformers. Calculating electromagnetic forces in transformers winding during short circuit conditions in different coil shapes. Studding the effect of the shape of the coils on the calculation of the electromagnetic forces in them. This work can save time, effort, and cost for transformer manufacturers in calculating the electromagnetic forces, also using this model for the virtual test leads to avoid the risk, and efforts spent to do the real short-circuit test.

show abstract

Short-circuit stress calculation in oval windings

Cited by 3 publications

References 0 publications

Critical stress of oval foil winding with epoxy coated insulation determined using measured equivalent modulus of elasticity

Critical stress of oval foil winding with epoxy coated insulation determined using measured equivalent modulus of elasticity

Analysis of Three-Phase Short-Circuit Electrodynamic Variation Characteristics of Power Transformers

Finite-Element Calculation of Electromagnetic Forces in the Deferent Shapes of Distribution Transformers Winding Under Short Circuit Condition

Contact Info

Product

Resources

About