• 전기의세계
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• v.24 no.4
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• pp.73-76
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• 1975

In this study, a design scheme of an impulsive high current generating device is presented. The device is proved to be effective in producing rather complex type of the permanent magnet. Principally, the apparatus designed same to the ordinary potential transformer or current transformer, but, it has a certain differences that the primary winding of many turns is excited by d.c. source and the secondary winding of a few turns induce low voltage and high current at the instant when opening a switch in the primary circuit. This paper does not include magnet production process. Rather, it deals with the analytical studies of the devices, the designing procedure of the experimental setup, and some results from the experimental data are presented as a preliminary study. The experimental results are found to agree well with the theoritical analysis presented in this paper.

• Proceedings of the KIEE Conference
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• 1992.07a
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• pp.491-494
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• 1992

This paper described the development example of optical CT(Current Transformer) and optical PT (Potential Transformer) which is measurement system of current and voltage of electric power line using Electro-Optic effect and Magneto-Optic effect. We designed the optical CT of 22KV class and 154KV class and an optical PT of 22KV class. And now the filed testing is in progress in a KEPCO's substation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.3
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• pp.367-372
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• 2012

In nuclear plants, UVR (under voltage relay, 27r) of 1E bus, which protected and supplied power to essential loads, to safety trip of reactor and supplied to starting signal of EDG (emergency diesel generators) automatically. therefore UVR tolerances setting and calculation method has been important to nuclear facility. If calculation and tolerances values differ or ignore, may induced power loss and economical loss by protective failure. This paper show results for calculation methods, and whether dependant or independent methods for factors. included whether PT (potential transformer/voltage transformer) tolerance or not adapted, and based on UVR setting method within a difference minimum and maximum of rated voltage to safety operation in nuclear plants.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1894-1895
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• 2007

It is excitation system for nuclear emergency generator that is to startup automatically and sequentially supply essential loads with power. There are static type and alternating exciter, etc in its excitation system. An object of study is static excitation system which power is taken from power potential transformer and power current transformer. It is to complement curtailment of excitation system ability at happening short accidents. And Startup mode are quick startup and slow startup, etc. Its characteristic is looked into in this paper.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.511-517
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• 2016

Current oil-type potential transformers for trains are filled with insulating oil, which could have problems like explosions due to rising inner pressure during train operation. Therefore, mold and dry-type potential transformers are being developed to prevent explosions. One problem in manufacturing mold-type transformers is preventing void formation around the coiled core inside the mold during epoxy filling, which could cause an electrical spark. Micro voids can remain in the resin after filling, and macro voids can occur due to the structure shape. A transformer that is being developed has a cavity at the junction of the core and the coil for better performance, and when highly viscous epoxy flows inside the cavity channel, macro voids can form inside it. Therefore, in this study, the free-surface flow of the mold filling procedure was analyzed numerically by applying the VOF method. The results were used to understand the phenomena of void formation inside the cavity and to modify the process conditions to reduce voids.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.2184-2186
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• 1997

Potential-source controlled rectifier excitation system has been developed by KEPRI for synchronous generator in YOUNG-DONG thermal power plant. This paper describes the characteristics of redundant control system and transfer function of dual channel excitation control system. This system has been using a analog and digital circuit devices(hybrid type)

• Proceedings of the KIEE Conference
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• 1990.07a
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• pp.3-6
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• 1990

The impact of the convected charges, which is caused by the electrification phenomina, in the oil-paper insulation systems of power transformers has been numerically investigated using FEM. The potential distribution of the oil-paper insulation system is assumed to be governed by three equations instead of the classical Laplace equation. When the charge density of oil and the conduction current are kept high, the field distortion or the interrace in a power transformer is considerably distorted due to the convected charges.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1387_1388
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• 2009

High accurate and stable 132 kV potential transformers (PTs) including 66 kV & 22 kV PT with stability of less than 0.0033 % for 13 month and with ratio error within $\pm$ 0.024 % at full rated voltage have been developed. The PTs are useful as the reference PT of the PT comparator system in the voltage range of 11 kV to 132 kV PT.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.4
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• pp.503-508
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• 2012

Among the high distribution voltage consumers, high-capacity consumers are often applying the grounding resistance method in order to overcome demerits such as erroneous operation of the ground reply or potential increase in the battery at the accident of the isolated neutral system. In this paper, to prevent damage to CLR and GPT in the delay to block the breakdown in the resistance grounded neutral system, this study aims to provide a proper suggestion for continuous rating capacity of GPT to check the appropriateness of CLR size and reduce GPT burden. Thereupon, this study comparatively analyzes CLR current applied in general GPT and the current gained when CLR demanded in the system is used and analyzes the simulated system through simulation using PSCAD/EMTDC in order to suggest GPT's proper continuous rating capacity.

• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.258-261
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• 2009

This paper proposes an earthing system without ground connection. As a Green IT Environmental Solution, Internal-external surge and other unnecessary electric currents are converted into energy and through a discharge the signal is reduced. It's a structure that discharges through a neutral electric transformer. The results show that the electric potential rising of the earthing system proposed in this paper are approximately below the half and the discharge currents increased approximately 9 times when compared to existent earthing systems. This earthing system is economical, easy to install and can solve environmental contamination.