• Proceedings of the KIEE Conference
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• 2004.04a
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• pp.12-14
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• 2004

Superconducting transmission power cable is one of interesting parts in power application using high temperature superconducting wire. One of import ant parameters in high-temperature superconduting (HTSC) cable design is transport current distribution because it is related with current transmission capacity and AC loss. In this paper, the transport current distribution at conducting layers was investigated through the analysis of the equivalent circuit for HTSC power cable with shield layer and compared with the case of without shield layer. The transport current distribution due to of the contact resistance and the pitch was improved in the case of HTSC power cable with shield layer from the analysis.

• Proceedings of the KIEE Conference
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• summer
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• pp.1133-1135
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• 2004

Superconducting transmission power cable is one of interesting parts in power application using high temperature superconducting wire. One of important parameters in high-temperature superconducting (HTSC) cable design is transport current distribution because it is related with current transmission capacity and ac loss. In this paper, the transport current and magnetic field distributions at conducting layers were investigated through the analysis of the equivalent circuit for HTSC power cable with shield layer. The transport current distribution due to the pitch length and winding direction was improved in case of HTSC power cable with shield layer.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.101-103
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• 1996

Multiply-twist cable is used for a large capacity superconducting cable because it is helpful to reduce AC losses and to increase transport current. In a multiply-twisted cable, the axis of a strand does not coincide with that of cable. Therefore, the longitudinal field is generated by the transport current. The longitudinal field changes the current distribution in the strand and generates additional AC loss. This paper calculates the longitudinal field that is applied to a strand in the multiply-twisted cable. Current distribution of a strand in the cable is also presented. 2nd level superconducting cable is chosen as an analysis model, whose current capacity is 2000A. Calculation result shows the longitudinal field cannot be neglected in low field machines such as superconducting transformer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05b
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• pp.123-126
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• 2003

고온초전도테이프의 전력부야 응용에서 자화손실과 함께 매우 중요한 통전손실에 대한 실험적 조사 연구를 한 결과, 외부자장이 커짐에 따라서 직류전압이 급격히 증가하였으며, 자장의 세기가 동일할지라도 교류인 경우가 직류인 경우보다 대단히 크다. 그리고 외부교류자장에 대한 직류전압-전류 특성으로부터 정의되는 동저항 또한 외부교류자장의 세기에 따라서 상이하지만 테이프의 임계전류에서 전기저항$(3.7\;{\mu}{\Omega}/m)$과 비교하여 작게는 수배에서부터 크게는 수백 배까지 증가한다.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.810-812
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• 2000

Superconducting transmission cable is one of interesting part in power application using high temperature superconducting wire as transformer. One important parameter in HTS cable design is transport current distribution because it is related with current transmission capacity and loss. In this paper, we calculate inductance and current distribution for 4-layer cable using the electric circuit model and compare calculation results of transport current losses by monoblock model and Norris equation

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.398-399
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• 2008

Enhanced performances of high temperature superconducting (HTS) cable attract tremendous interests of the power utility. However, the reliability issue as the power system is still in controversy. To verify the reliability of HTS cable, 22.9 kV HTS cable system with the specification of 100 m length, 50 MVA capacity, and open refrigeration cooling system was laid on Gochang power testing center of KEPCO in 2006. During the test period, the current transport characteristics, the fundamental function of power cable, have been monitored and investigated precisely. In this paper, the heat loss and AC loss measured at various current load conditions are described and discussed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.535-538
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• 2004

Superconducting transmission power cable is one of interesting parts in power application using high temperature superconducting wire. One of important parameters in high-temperature superconduting (HTSC) cable design is transport current distribution because it is related with current transmission capacity and AC loss. In this paper, the transport current distribution at conducting layers was investigated through the analysis of the equivalent circuit for HTSC power cable with shield layer and compared with the case of without shield layer. The transport current distribution due to the pitch lenght was improved in the case of HTSC power cable with shield layer from the analysis.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.603-604
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• 2000

Bi-2223 테이프는 송전케이블과 같은 저 자장 전력시스템의 응용에 가장 유망한 선재로 알려져 있다. 송전케이블에 교류 전류가 인가되면 인접한 테이프에 의해서 발생되는 자계는 통전손실에 영향을 미치게 된다. 이와 같은 실제 송전케이블의 응용 측면을 고려하여 좌측 및 상부인접전류가 통전손실에 미치는 영향에 대하여 조사하였다. Bi-2223 테이프의 통전손실은 교류 인접전류가 증가함에 따라서 급격하게 증가하는 반면, 직류 인접전류의 영향은 무시 가능한 정도로 작았으며, 인접전류가 큰 경우는 테이프의 배열에 무관한 반면 작은 경우에는 상부배열인 경우의 영향이 큼을 알 수 있었다. 또한 Bi-2223 테이프의 통전손실은 교류 인접전류의 주파수에 무관함을 알 수 있었다.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.16 no.1
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• pp.11-21
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• 2020

This study aims to develop and advance the evaluation technology for assessing PHWR safety. For this purpose, the complete loss of AC power or station blackout (SBO) was selected as a target accident scenario and the analysis model to evaluate the plant responses was envisioned into the MARS-KS input model. The model includes the main features of the primary heat transport system with a simplified model for the horizontal fuel channels, the secondary heat transport system including the shell side of steam generators, feedwater and main steam line, and moderator system. A steady state condition was achieved successfully by running the present model to check out the stable convergence of the key parameters. Subsequently, through the SBO transient analyses two cases with and without the coolant leakage via the PHTS pumps were simulated and the behaviors of the major parameters were compared. The sensitivity analysis on the amount of the coolant leakage by varying its flow area was also performed to investigate the effect on the system responses. It is expected that the results of the present study will contribute to upgrading the evaluation technology of the detailed thermal hydraulic analysis on the SBO transient of the operating PHWRs.

• Journal of the Korean Ceramic Society
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• v.44 no.12
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• pp.696-702
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• 2007

The family of (Sr,Mg)-doped $LaGaO_3$ compounds, which exhibit high ionic conductivity at $600-800^{\circ}C$ over a wide range of oxygen partial pressure, appears to be promising as the electrolyte for intermediate temperature solid oxide fuel cells. Conventional synthesis routes of (Sr,Mg)-doped $LaGaO_3$ compounds based on solid state reaction have some problems such as the formation of impurity phases, long sintering time and Ga loss during high temperature sintering. Phase stability problem especially, the formation of additional phases at the grain boundary is detrimental to the electrical properties of the electrolyte. From this point of view, we focused to synthesize single phase (Sr,Mg)-doped $LaGaO_3$ electrolyte at the stage of powder synthesis and to apply relatively low heat-treatment temperature using novel synthesis route based on combustion method. The synthesized powder and sintered bulk electrolytes were characterized by XRD, TG-DTA, FT-IR and SEM. AC impedance spectroscopy was used to characterize the electrical transport properties of the electrolyte with the consideration of the contribution of the bulk lattice and grain boundary to the total conductivity. Finally, relationship between synthesis condition and electrical properties of the (Sr, Mg)-doped $LaGaO_3$ electrolytes was discussed with the consideration of phase analysis results.