A Novel Approach to Investigate the Hot-Spot Temperature Rise in Power Transformers

Li, Longnv; Niu, Shuangxia; Ho, S. L.; Fu, Weinong; Li, Yan

doi:10.1109/tmag.2014.2359956

Cited by 26 publications

(8 citation statements)

References 8 publications

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“…al. [13] have presented an accurate computational alternative for hot-spot temperature-rise estimations in a single-phase auto-transformer to compute the stray losses using finite-element method (FEM), along with the average surface convection heat transfer coefficients of the structural parts of the transformer. Radakovic et.…”

Section: State Of Artmentioning

confidence: 99%

Estimation of Loss of Life due to Hot Spot Development in Power Transformer using MATLAB

2016

IJCCIE

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The opportunity for the research in thermal modeling of power transformer is to estimate their loss of life due to overloading by employing the winding hot spot temperature (HST) and by carrying out aging studies based on heat transfer theory. This is facilitated by developing computational thermal models and their simulation using appropriate software tools. These models are employed to evaluate the actual functional age of transformers by estimating enhanced equivalent life at the reference temperature that will be spent over the specified time period for the given temperature cycle due to acceleration of aging. This paper presents a MATLAB/ Simulink based model for this purpose. The life determines the aging acceleration factor, which has been used for estimation of the loss of life of the transformer. Further, the effect of cooling for reducing the loss of life has also been studied. The proposed model has been validated using real time data gathered from a power transformer in field operation.

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Section: State Of Artmentioning

confidence: 99%

Estimation of Loss of Life due to Hot Spot Development in Power Transformer using MATLAB

2016

IJCCIE

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“…It was observed that by applying PCM the temperatures were decreased by about 8°C. Li et al 5 conducted a numerical study to investigate the hot-spot temperature rise in power transformers by proposing a new approach. They used a 3-D magnetic-thermal coupling analysis with CFD computation to determine the hot-spot temperature rise.…”

Section: Introductionmentioning

confidence: 99%

A numerical study on effect of intra and inter spaced winding configuration on performance of oil forced transformer cooling system

Muralikrishna,

Satyanarayana Reddy,

Sahu

et al. 2024

Proceedings of the Institution of Mechanical Engineers, Part A:

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The present work aims at investigating, numerically, the heat transfer characteristics of transformer cooling system under forced circulation for three different winding configurations. The purpose of a transformer cooling system is to keep the hot spot temperature within the critical value for a long life of transformer, which increases with enhanced cooling of transformer windings. Thus, two different winding configurations are modeled by providing space within the windings (an intra-space model) and in between the windings (an inter-space model) to improve the fluid-solid interaction. A conventional winding, without spacing, is also modeled for comparative study. A 315 kVA, 3-phase core type transformer is taken as the base model from which the winding and core specifications are obtained analytically. Parameters chosen to measure the influence of winding configuration are local temperature distribution in the windings and core and maximum transformer temperature. Results are obtained for all three models with varying space for various cooling mediums like naphthenic oil, silicon oil, and synthetic ester oil at flow velocities ranging from 0.72 m/s to 2.16 m/s. It is observed that the gap between the windings, interspacing, decreases the secondary winding temperatures, while it increases the core and primary winding temperatures. However, the intra spacing configuration finds a drop in local temperatures at all locations of the transformer windings and core. The enhanced heat dissipation to the cooling agent, with intra spacing winding configuration, reduces the maximum transformer temperature. Contrasting to the above, the inter-space model has an adverse effect on maximum temperature at all widths of space considered. Quantitatively, the space within the transformer reduces the maximum temperature by 5% in comparison with the space between the windings. The increased velocity of the cooling medium, Naphthenic oil, from 0.72 m/s to 2.16 m/s reduces the maximum temperature by 4.5 units. The study made to know the role of cooling medium discloses that the synthetic ester oil shows better performance for reducing temperature values due to its highly viscous nature.

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“…In order to improve the cooling efficiency, the internal liquid cooling technology has been studied and developed to avoid the internal components being directly exposed to the coolant, and an indirect liquid cooling structure has been proposed [9], [10]. A self-circulating oil cooling system for hollow shaft is proposed, which can effectively enhance the heat transfer capacity of the shaft [11].…”

Section: Introductionmentioning

confidence: 99%

Cooling Structure Design of High-Speed Permanent Magnet Synchronous Machine With Axial Ventilation Self-Cooling Rotor

Luo,

Zhang,

Wang

et al. 2024

IEEE Access

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In order to address the challenges of high loss density, difficult heat dissipation, and irreversible demagnetization in high temperature of high-speed permanent magnet machine, an innovative cooling structure with axial ventilation and self-cooling rotor is proposed to enhance temperature distribution. The cooling efficiency of the cooling structure is defined, and the influence of the rotor vent on the electromagnetic and air friction loss is analyzed. The governing equation for the fluid flow in a rotating pipe is derived from a fluid model analysis of a ventilation hole rotating at any angle to the axis of rotation. The calculated results are validated against the results obtained from computational fluid dynamics. The sensitivity of rotor cooling performance to various control factors using the variance index method. Subsequently, the cooling structure was enhanced based on the findings of the analysis. The calculation results indicate that the heat dissipation effect of the axial ventilation self-cooled rotor has decreased by 4.17 ℃ compared to before the improvement. The temperature rise experiment verified the accuracy of temperature calculation and the effectiveness of the cooling structure, providing strong support for the design of axial self-ventilation cooling system for high-speed machines.INDEX TERMS cooling structure, heat dissipation, high-speed machine, permanent magnet synchronous machine

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A Novel Approach to Investigate the Hot-Spot Temperature Rise in Power Transformers

Cited by 26 publications

References 8 publications

Estimation of Loss of Life due to Hot Spot Development in Power Transformer using MATLAB

Estimation of Loss of Life due to Hot Spot Development in Power Transformer using MATLAB

A numerical study on effect of intra and inter spaced winding configuration on performance of oil forced transformer cooling system

Cooling Structure Design of High-Speed Permanent Magnet Synchronous Machine With Axial Ventilation Self-Cooling Rotor

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