• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.212-215
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• 2003

In this paper, a model pole transformer was designed to improve the reliability of pole transformers and its short circuit withstand strength was tested. The failure causes of the pole transformers which had been operated in the field were analyzed and several patterns of the causes were determined. A novel countermeasure was devised to prevent the failures of the pole transformers in advance. A model pole transformer was designed and made in accordance with the given specifications to strengthen the short circuit withstand capability and its characteristic was tested. As a result, the advanced performance of the model pole transformer was confirmed and novel techniques in manufacturing process was suggested. It is considered that all the methods employed in the developing process will be helpful to design and manufacture the pole transformers thus the reliability of pole transformers in distribution lines will be improved.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.53 no.2
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• pp.87-96
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• 2004

This paper summarizes the research results of the load management for pole transformers done in 1997-1998 and 2000-2002. The purpose of the research is to enhance the accuracy of peak load estimation in pole transformers. We concentrated our effort on the acquisition of massive actual load data for modifying the load regression coefficients, which related to the peak load estimation of lamp-use customers, and adjusting the demand-factor coefficients, which used for the peak load prediction of motor-use customers. To enhance the load regression equations, the 264 load data acquisition devices are equipped to the sample pole transformers. For the modification of demand factor coefficients, the peak load currents are measured in each customer and pole transformer for 13 KEPCO (Korea Electric Power Corporation) distribution branch offices. Case studies for 50 sample pole transformers show that the proposed coefficients could reduce estimating error of the peak load for pole transformers, compared with the conventional one.

• KIEE International Transactions on Power Engineering
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• v.2A no.3
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• pp.114-120
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• 2002

This paper describes the symptoms with the fault causes of pole transformers analyzed by Korea Electric Power Corporation(KEPCO) branch offices' request in 2001, and ultimately aims to devise proper countermeasures against the faults. The fault causes are generally divided into problems in manufacturing, mounting and operating. The pole transformers encounter the fault with unique aging mechanisms. To verify the mechanisms with the faults and to devise proper countermeasures, a flowchart for analyzing the fault causes is proposed, by which the fault causes of the pole transformers can be analyzed more exactly.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.503-507
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• 2002

This paper describes the symptoms with the failure causes of pole transformers analyzed at KEPCO branch offices' request in 2001, and ultimately aims for devising proper countermeasures against the failures. The failure causes are generally divided into problems in manufacturing, mounting and operating. The pole transformers encounter the failure with unique mechanisms. To verify the mechanisms to failures and help devise proper countermeasures, a flowchart is proposed based on the authors' experience and foreign case studies. The failure causes of pole transformers can be analyzed more exactly by using the flowchart.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.9
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• pp.1507-1515
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• 2008

It is essential for electric power companies to have a quick restoration system of the faulted pole transformers which occupy most of transformers to supply stable electricity. However, it takes too much time to restore it when a transformer is out of order suddenly because we now count on operator in investigating causes of failure and making decision of recovery methods. This paper presents the concept of 'Fault pattern analysis and Restoration prediction model using Data mining techniques’, which is based on accumulated fault record of pole transformers in the past. For this, it also suggests external and internal causes of fault which influence the fault pattern of pole transformers. It is expected that we can reduce not only defects in manufacturing procedure by upgrading quality but also the time of predicting fault patterns and recovering when faults occur by using the result.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.464-466
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• 2000

In this paper, the high frequency models of pole-transformers are provided to confirm the feasibility of PLC systems between high and low voltage distribution systems. The impedance of transformers is measured to verify the characteristics of transformers at high frequency from 100[kHz] to 1[MHz] and the equivalent circuits of the transformers were designed based on the measured impedance. The signals transmitted from the primary and the secondary sides of the transformers were measured, respectively. The transmission loss of the transformers was obtained by the measured signals. Numerical analysis using the equivalent circuit is compared to the measured signals. The possibility of communication through pole-transformers is presented by experiments and simulations.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.1
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• pp.37-44
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• 2003

This paper proposes on-line based a deterioration diagnosis pole transformers using various sensors such as thermistor, current transformer and potential transformer. We measured load current and temperature to diagnose pole transformer using R/F( radio frequency ) wireless data communication module. We represent the graphs of their feature. The result of this paper shows that the proposed device car be used as deterioration diagnosis device of pole transformers.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1591-1593
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• 2001

In this paper, the electrical characteristics of Insulating paper, for pole transformers, subjected to accelerated ageing were observed and the results were compared with those of virgin insulating paper. For the experiment, insulating materials for pole transformers were enclosed together in an oil bath and thermally aged under the real pole transformer operating conditions. After the accelerated ageing of the insulating materials, the dielectrics were measured and compared with the results of the virgin ones.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1558-1560
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• 2004

Liquid-immersed pole transformers have utilized an insulation system consisting of natural cellulose-based materials and mineral oil for many years. If the transformers are installed with the abruptly changing load over limitation, its insulation materials are apt to unexpected aging with high temperature. Therefore we have been conscious of developing a transformer that is more thermally stable then conventional types. To measure temperature distribution in the winding of conventional and newly designed transformers, temperature sensors were installed fordirect reading of oil and conductor temperatures at transformers. And we conducted accelerating aging test for these transformers. The measuring data had made use of the design to hybrid insulation system. Also we could find the possibility of this insulation system to apply in pole mounted transformers.

• Proceedings of the KIEE Conference
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• 2004.11d
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• pp.97-99
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• 2004

Liquid-immersed pole transformers have utilized an insulation system consisting of natural cellulose-based materials and mineral oil for many years. If the transformers are installed with the abruptly changing load over limitation, its insulation materials are apt to unexpected aging with high temperature. Therefore we have been conscious of developing a transformer that is more thermally stable then conventional types. To measure temperature distribution in the winding of conventional and newly designed transformers, temperature sensors were installed fordirect reading of oil and conductor temperatures at transformers. And we conducted accelerating aging test for these transformers. The measuring data had made use of the design to hybrid insulation system. Also we could find the possibility of this insulation system to apply in pole mounted transformers.