• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.653-655
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• 1992

Longitudinal and transverse normal zone propagation in the superconducting coil are analyzed and propagation velocity is derived from the heat balance equations in the propagating boundary region. Transverse velocity is nearly $10^{-2}$ order of longitudinal velocity. Propagation velocity ie linearly proportional to the transport current. Increasing lamp current speeds up longitudinal velocity by 0.279 m/s under the applied field of 2T. Transient heat transfer has a significant effect on normal zone propagation velocity and it decreases longitudinal velocity by 4.2 m/s under the applied field of 2T as being compared to steady-state heat transfer.

• 대한전기학회논문지
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• 제43권7호
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• pp.1041-1049
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• 1994

Longitudimal and transverse normal zone propagations in the superconducting coil are analyzed and propagation velocity is derived from the heat balance equations in the propagating boundary region. The results of applying to the specific superconducting wire show that propagation velocity is linearly proportional to the transport current and increasing ramp current speeds up the longitudinal velocity by 1.22[m/s] under the applied field of 2T. Transient heat transfer has a significant effect on the normal zone propagation velocity and it decreases longitudinal velocity by 5.2[m/s] under the applied field of 2T as being compared to the steady-state heat transfer. Increasing ramp current speeds up the Z-axis transverse propagation velocity by 0.042[m/s] and transverse velocity of R and Z axis is costant regardless of the current flows.

• 한국초전도ㆍ저온공학회논문지
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• 제13권3호
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• pp.24-30
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• 2011

The stability issue of high temperature superconducting (HTS) racetrack coils is one of the most important factors for the development of large-scale rotating machines, such as ship propulsion motors and power generators. However, The stability and normal zone propagation characteristics of HTS racetrack pancake (RP) coils are not sufficient yet. In this study, quench tests for a GdBCO racetrack pancake coil were carried out under the condition of $LN_2$ at 77 K. Minimum quench energy and two-dimensional normal zone propagation velocities of the coil are also discussed. Normal zone propagation velocity in the coil's curved section is faster than in its straight section due to stress effects. The test results show that the protection of the straight section is of greater importance than that of the curved section when GdBCO racetrack pancake coils are applied to large-scale rotating machines.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.448-451
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• 2000

Normal zone propagation(NZP) characteristics were investigated on Ag sheathed Bi-2223 tape and cylindrical stacked conductor. Normal zone propagation(N2P) experiments with tape were conducted with refrigerator in temperature from 45 K to 77 K, 0 T. Cylindrical stacked conductor was molding with epoxy and experiments were conducted with adiabatic condition in $LN_2$. NZP velocities of tape with two condition of DC and AC were almost same at each temperature. NZP velocities of cylindrical stacked conductor were 1.9-2.4 cdsec in $LN_2$. Numerical analysis was carried out by a one-dimensional heat balance equation. As a result, simulated results of NZP velocity with Bi-2223 tape were similar to experimental results in DC.

• 한국전기전자재료학회논문지
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• 제14권4호
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• pp.345-350
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• 2001

Normal zone propagaton(NZP) properties were investigated on Bi-223/Ag tapes and prototype HTS cable. NZP experiments in tape were conducted in temperatures from 45K to 77K in zero field. Prototype HTS cable was molded using epoxy and the experiments were carried out under adiabatic condition in LN$_2$. NZP velocities in tapes with tow conditions of DC and AC currents were almost same at each temperature. NZP velocity in prototype HTS cable was 1.9-2.4 cm/sec in LN$_2$. Numerical analysis was carried out by a one-dimensional equation of heat balance. The simulation results of NZP velocity in Bi-2223/Ag tapes were similar to the experimental results.

• 한국초전도ㆍ저온공학회논문지
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• 제1권2호
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• pp.43-48
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• 1999

The normal zone propagation (NZP) velocity and V-I characteristics of two Bi-2223 pancake coils with different Ag/SC ratio were investigated based on the experimental results and broad resistive transition were obesved in two coils. The measured NZP velocity of coil was found to be faster due to increase of Ag/SC ratio, and agree well with calculated data from two dimensional heat balance equation.

• 한국초전도ㆍ저온공학회논문지
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• 제2권1호
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• pp.36-39
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• 2000

The main issues for the power application of high Tc superconducting tape are lower AC loss and higher stability conditions. HTS tape has large stability margin by high heat capacity of superconductor itself and high temperature margin. But, it can be damaged by continuous heat generation at quench point, because normal zone propagation velocity by generating heat is very low. Here, we analyze the quench propagation characteristics using finite element method for BSCCO-2223 HTS tape.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 A
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• pp.82-84
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• 1998

The normal zone propagation velocity and minimum quench energy (MQE) of cable-in-conduit conductors (CICC) has been investigated at the different background magnetic fields and supercritical helium pressures. The sample CICC of 2 m in length was fabricated with triplet NbTi/Cu strands inserting into a round stainless-steel tube. The heat pulse disturbance with duration time about 400 ms was acted on the center region of the CICC to quench the strands. The normal zone propagation velocity increased with operating current of the CICC. The measured velocity with respect to operation current could be fitted with numerical results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.184-186
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• 1996

This paper is a study on the analysis of normal zone propagating velocity in high Tc superconductor. Steady-state solution is analyzed based upon the one-dimensional heat transfer equation. This model incorporates the temperature and magnetic field dependent superconductor properties. The analytical results indicate that the propagation velocity is not a linear function of operating current, magnetic field and temperature.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 1999년도 제1회 학술대회논문집(KIASC 1st conference 99)
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• pp.109-112
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• 1999

The normal zone propagation (NZP) velocity and V-I characteristics of two Bi-2223 pancake coils with different Ag/SC ratio were investigated by experiment. Non-uniformity of Ic and broad restive transition was oberserbed in two coils. The NZP velocity of azimuth direction is faster than radius direction, and the NZP velocity of coil with higher Ag/SC ratio is faster than another coil with lower Ag/SC ratio.