• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.7
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• pp.367-372
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• 2006

A novel coil gun type actuator has been proposed and tested for its possibility as an actuator for a high voltage circuit breaker by experimental method. The 20kJ capacitor bank with the electrolytic condensers was charged up to 500V and discharged to a couple of 100 turn coils connected with parallel through a thyristor switch. The repulsive force between coil and the actuator made by copper conductor of 20kg reached up to 23,000 N, and over 800J of energy was transferred to the kinetic energy of the conductor. The experimental results showed that the coil gun type actuator has a good possibility for the high voltage circuit breaker.

• Progress in Superconductivity and Cryogenics
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• v.3 no.2
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• pp.27-31
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• 2001

This paper deals with the numerical estimation of the bubble behavior and the partial discharge (PD) initiation voltage on the basis of electric field calculation with the coaxial coil layer-to-cylindrical electrode system for the simulation of high temperature superconducting coils. The theoretical results of bubble behavior and the PD initiation voltages show fairly good agreement with the experimental results.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.12B no.1
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• pp.7-12
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• 2002

This paper presents a method to estimate an effective length of a 1000-kVA superconducting generator using three-dimensional FE analysis. Flux linkage of stator coil and the induced voltage are calculated with FEM program and Faraday's law. An effective length of the stator coil is estimated using the calculated voltage and geometric configurationn of the machine. In order to verify the estimation method, 30-kVA superconducting generator is built and tested. The test result agrees reasonably well with the estimation.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.32 no.8
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• pp.277-283
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• 1983

The pulse generating circuit system of the so-called turbulently-heated theta pinch is experimentally investigated, and its results are compared with the predictions based on the conventional theory. The conventional theory assumes that the impedance of the pinch coil is independent on the time rate of change in voltage (or current) across the pinch coil. The experimental pulse height of the voltage actross the pinch coil is about 1.5% fo that predicted by the conventional theory.

• Applied Science and Convergence Technology
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• v.26 no.5
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• pp.114-117
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• 2017

Plasma characteristics of two-dimensional inductively coupled discharge simulation is investigated. Impedance of an inductively coupled plasma discharge was considered. Voltage drops across antenna coils and current variation between coils made different profiles of plasma characteristics. Importance of the capacitive field effect in some case was analyzed.

• Progress in Superconductivity and Cryogenics
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• v.4 no.1
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• pp.94-98
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• 2002

The Partial breakdown (PBD) and complete breakdown (BD) voltage characteristics in a composite insulation system of glass fiber reinforced plastics (GFRP) and liquid nitrogen are investigated to find the PBB and BD characteristics in solenoid type high temperature superconducting (HTS) coils at quench. The electrode system used is made from a coaxial spiral coil-to-cylindrical electrode with an insulation barrier and spacers, and is immersed in liquid nitrogen. A heater is mounted inside the coil electrode to generate boiling which occurs on quenched superconducting coils. The experimental results show that: (1) breakdown voltages are affected severely by the risetime of the applied voltage and the PBD inception voltage, (2) two kinds of BD mechanisms are found depending on the shape of the spacer, length of cooling channel and heater power.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.943-944
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• 2007

In this paper, the development and the test of 13.2kV/630A high-Tc superconducting fault current limiting coil are described. The fault current limiting coil made of Coated Conductor (CC) was fabricated with bifilar winding method for non-inductive characteristics and tested in the distribution power system level in Dec. 2006. In order to determine the length of the superconducting coil, applied voltage per unit length(V/m) was studied analytically and it was verified through experiments. For the volume minimization, the coil was designed with concentrical arrangement method. The short-circuit test was performed with the prospective fault current of asymmetrical 10kA whose maximum fault current was $30kA_{peak}$. In the test, the voltage drop and the current of the coil were measured and the resistance of the coil was obtained. Also, the temperature rise of the coil was calculated with the relationship between the resistance and the temperature of CC. In this paper, the experimental results are analyzed and compared with the simulation.

• Progress in Superconductivity and Cryogenics
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• v.3 no.1
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• pp.16-21
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• 2001

Bubble behavior is studied with an electrode system which consists of coaxial spiral coil-to-cylindrical electrode with an insulation barrier and spacers and is immersed in liquid nitrogen for simulation of insulation environments in high temperature superconducting(HTS) coils The results show that the bubble behavior Is affected severely by electric field: (1) under low applied voltage bubbles rise by buoyancy, but at higher applied voltage they are trapped in a lower electric field region below the coil electrode, and (2) the trapped bubble flows along the downside of coil electrode if no obstruction is in a groove between coil turns. but it splashes out of the groove after its growing if the obstruction such as spacer-exists.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2002.02a
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• pp.185-188
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• 2002

In the design of superconducting power equipments such as transformer, cable and fault current limit, knowledge of the dielectric behavior of both liquid and gaseous at very low temperatures is very importance. Especially, Electrical properties of liquid nitrogen($LN_{2}$) and gaseous nitrogen($GN_{2}$) have become of great interest again since the discovery of high temperature superconductors. However, many sources of $LN_{2}$and $GN_{2}$ problems in the test of pancake coil model arising form the deficiency of insulation data. Therefore, this paper describes the results of an experimental study on the ac breakdown voltage($V_{B}$) properties of $LN_2$ and Air under the electrode of simulated HTS pancake coil. The ac breakdown voltage of $GN_{2}$ have been measured by pancake coil-pancake coil gaps over the temperature range of 293 K to 77 K.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.494-498
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• 2002

HTS transformer experimentally. High temperature superconductors can only be applied against an engineering specification that has to be determined for each particular application form the design requirements for economic viability and for operation margins in service. High temperature superconducting(HTS) power apparatus are very promising candidates for application. Especially, these advantages make superconducting transformers very promising candidates for application in electrical power engineering and locomotives. In order to realize the HTS transformer, it is necessary to establish the high voltage insulation technique in cryogenic temperature. So far, insulation research of Pancake type HTS transformer is lacking nothing but insulation research of . solenoid type transformer consisted. Therefore, the composite insulation of double pancake coil type transformer are described and ac breakdown voltage characteristics of liquid nitrogen(LN$_2$) under HTS pancake coil electrode made by Bi-2223/Ag are studied. Breakdown in LN$_2$ is dominated electrode shape and distance. The relation between surface flashover voltage is considered for FRP. This research presented basis information of electrical insulation design for double pancake coil type HTS transformer.