• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.1
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• pp.90-94
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• 2009

The inundation of substation and ground power equipment breaks out every summer season in low-lying downtown and low-lying shore by localized heavy rain, typhoon and tidal wave. For diminishing flood damage of electrical equipment in the root, flood protection system which is used the basic frame of Pad transformer is developed using pneumatic pressure. This system is established on pressure generator equipment and sensor of flooded level operates at flooding occurrence and is maintained a shutting tightly structure. The system is able to protect indraft water in Pad Transformer and supply the electricity at emergency(flooding). And we tested safety for insulation resistance at flooding and applying an electrical current. We estimate that loss cost which is caused by with flooding and the power failure will be diminished if it is addition to advances the reliability evaluation by setting an example.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1350-1352
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• 1995

This paper discribed the characteristic of I-t cross-over-point between current limited-fuse and explusion fuse(Bay-O-Net Fuse) and fuse protection in pad-mounted transformer that was generated internal faults and the short circuit of secondary side(load side). In the I-t cross-over-point, current limited fuse was melted when transient recovery voltage was raised rapidly.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.3
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• pp.27-32
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• 2010

The inundation of substation and ground power equipment breaks out every summer season in low-lying downtown areas and low-lying shores by torrential rain, typhoons and tsunamis. It has, in turn, caused replacement, social and economic costs for blackouts. For activity management regarding flood damage we produced a flood protection system which using the Pad transformer as a basic frame and is developed using pneumatic pressure. We tested safety concerns including insulation resistance and current leakage first for water tank flooding and, second, by an empirical test through supplying 22.9[kV]. We estimate that costs associated with flooding and power failure can be diminished by these advances toward creating a more reliable system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.383-386
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• 2000

Fuse mounted elbow connector used for pad mounted transformer was designed and investigated. Requirements of electrical ratings such as partial discharge, ac withstand voltage and impulse voltage and material properties were proposed in accordance with IEEE 386 and pre-standard (PS) 147-219∼229 of KEPCO. The connector can be jointed with pad mounted transformer and current limiting fuse which is installed inside of the connector easily replaced with new one in the case of breakdown of the fuse. Electric field analysis was also introduced in other to verify the reliability of the design.

• KEPCO Journal on Electric Power and Energy
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• v.8 no.1
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• pp.5-7
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• 2022

KEPCO's plan is undergoing a trial operation to replace the open-loop section with ring main units configuration where underground distribution lines are installed, by linking the multi-way circuit breakers auto (MCA) on the power side of each pad-mounted transformer. However, ring main units application mentioned above may cause the ripple effects, when implementing the configuration without a study of protection coordination. Because ring main units with classical pre-set protection devices contribution in fault condition didn't consider yet. For the reliable ring main units operation, it is necessary to resolve several protection issues such as the protection coordination with substation side, prevention of the transformer inrush current. These issues can radically deteriorate the distribution system reliability Hence, it is essential to design proper protection coordination to reduce these types of problems. This paper presents a scheme of ring main units' configuration and MCA's settings of time-current curves to preserve the performance of protection coordination among the switchgears considering constraints, e.g. prevention of the ripple effects (on the branch section when a transformer failure occurs and the mainline when a branch line failure occurs). It was confirmed that the propagation of the failure for each interrupter segment could be minimized by applying the proposed TCC and the interrupter settings for the MCAs (branch, transformer). Further, it was verified that the undetected area of the distribution automation system (DAS) could be supplemented by having the MCA configurated ring main units operate first, instead of the internal protection equipment in the transformer such as the fuse, STP when a transformer failure occurs.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.6
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• pp.85-92
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• 2000

This paper has developed the system that can monitor the distribution transformers(pole and pad) using simplified deterioration detecting sensor in oil and wireless data communication. This system is made up by deterioration detecting sensor, oil level measuring system, deterioration measuring system and communication unit. To prove the usefulness of the system, the paper compared and analyzed the system with the existed system, and after studying the correlation of the both, the result proved goodness of the new system. The proposed monitoring system, when it is used on the pole and pad transformer, would make the reliable diagnoses possible with less rate.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1997.10a
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• pp.74-77
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• 1997

As underground distribution systems to be operated in downtown have more merits than overhead distribution system, underground distribution systems are being increased. But when pad-mounted transformers have troubles, reptures and fires can be occurred. We think that this makes accidents and power failures of bulidings and generates malaise and a great economic loss. In order to increase the reliability of pad-mounted transformers, we have investigated transformers and understood their failure mechani는. Therefore, we would have objectives and necessities of this study to improve quality and operating condition and install switches to be able to check and maintain transformers and optimize protection devices and increase cooling effect in pad-mounted transformers.

• Proceedings of the KIEE Conference
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• 1994.11a
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• pp.264-266
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• 1994

In this paper, we describe the thermal distribution characteristics of 1 phase, 22.9kV 200kVA, pad mounted transformer. We made pad. tr. which had 71 temperature measuring points in windings and case. In the results of pad. tr. temperature distribution, the highest and the lowest temperature points are placed in the high voltage windings and the temperature difference of high voltage winding is higher than that of low voltage winding.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.10
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• pp.1759-1766
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• 2008

According to the increase of power demand and expansion of downtown, it is necessary to install transformers additionally in operating substations and construct substations in residential area. But the public complaint has been increased due to the transformer noise of the substation. KEPCO has used a vibration preventing pad, various soundproof walls and an encloser to transformers in outdoor substations, and a soundproof door, shutter and wind-path soundproof equipment in indoor substations to block the sound propagation from the transformers. But these noise reduction methods are not satisfied. It should be considered to reduce transformer noise itself. In this paper, we investigated tank noise reduction techniques to develope a low noise transformer. According to the mode analysis of transformer tank, we found out characteristics and locations of noise on the tank, and it's nature vibration was also analysed. On the basis of these analysis, reinforcement equipment was installed around transformer tank, and ellipse shape tank was changed to round shape tank. The effect of noise reduction was evaluated using noise generation source.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.11
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• pp.1962-1969
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• 2008

According to the increase of power demand and expansion of downtown, it is necessary to install transformers additionally in operating substations and construct substations in residential area. But the public complaint is increased due to the transformer noise of the substation. KEPCO has used a vibration preventing pad, various soundproof walls and an encloser to transformers in outdoor substations, and a soundproof door, shutter and wind-path soundproof equipment in indoor substations to block the sound propagation of the transformers. But these noise reduction methods are not satisfied. It should be considered to reduce transformer noise itself. In this paper, we investigated core noise reduction techniques to develope a low noise transformer. The techniques to reduce core noise of the transformer are application of high permeability grain oriented silicon sheets, decrease of magnetic flux density of core, application of 6step-lap core stacking method, improvement of core binding method(binding addition, band fixing) and application of rubber damper in oder to reduce transmission of core vibration, etc.