Pub Date : 2020-12-01DOI: 10.9714/PSAC.2020.22.4.045
Jhongkwon Kim, Byeongchang Byeon, Kyoung Joong Kim, Sangkwon Jeong
{"title":"Enhancement of the round-trip efficiency of liquid air energy storage (LAES) system using cascade cold storage units","authors":"Jhongkwon Kim, Byeongchang Byeon, Kyoung Joong Kim, Sangkwon Jeong","doi":"10.9714/PSAC.2020.22.4.045","DOIUrl":"https://doi.org/10.9714/PSAC.2020.22.4.045","url":null,"abstract":"","PeriodicalId":20758,"journal":{"name":"Progress in Superconductivity and Cryogenics","volume":"22 1","pages":"45-50"},"PeriodicalIF":0.3,"publicationDate":"2020-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45015636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-01DOI: 10.9714/PSAC.2020.22.2.038
Jonghoon Yoon, U. Bong, Soobin An, S. Hahn
This paper presents comparative research on characteristics of air-cored and iron-cored high-temperature superconductor (HTS) field winding synchronous motors. The 100 kW air-cored model is designed analytically by Spatial Harmonic Method, and based on this model, the iron-cored model having the same output power is designed for comparison. Due to the substantial difference of permeability property between air and iron-core, there is a difference of magnetic field magnitude and angle with respect to the HTS tape c-axis, resulting in a different critical current of the field winding considering the anisotropic property of HTS tape. For a detailed comparison between two models, the following key motor characteristics are calculated through the Finite Element Method (FEM) simulation: 1) critical current; 2) HTS wire length; and 3) torque characteristics. From the simulation results, it can be confirmed that the critical current value of the iron-cored model increases by 33 %. Also, in the case of the superconducting wire consumption, those of the iron-cored and air-cored models are 95.3 m and 815.6 m, respectively. So the wire usage can be reduced to about 88 % by using iron core. However, in terms of torque characteristics, the torque ripple of the iron-cored model is about twice as large as that of the air-cored model, which may be a disadvantage on vibration and acoustic noise.
{"title":"Characteristics comparison between air-cored and iron-cored 100 kW HTS field winding synchronous motors","authors":"Jonghoon Yoon, U. Bong, Soobin An, S. Hahn","doi":"10.9714/PSAC.2020.22.2.038","DOIUrl":"https://doi.org/10.9714/PSAC.2020.22.2.038","url":null,"abstract":"This paper presents comparative research on characteristics of air-cored and iron-cored high-temperature superconductor (HTS) field winding synchronous motors. The 100 kW air-cored model is designed analytically by Spatial Harmonic Method, and based on this model, the iron-cored model having the same output power is designed for comparison. Due to the substantial difference of permeability property between air and iron-core, there is a difference of magnetic field magnitude and angle with respect to the HTS tape c-axis, resulting in a different critical current of the field winding considering the anisotropic property of HTS tape. For a detailed comparison between two models, the following key motor characteristics are calculated through the Finite Element Method (FEM) simulation: 1) critical current; 2) HTS wire length; and 3) torque characteristics. From the simulation results, it can be confirmed that the critical current value of the iron-cored model increases by 33 %. Also, in the case of the superconducting wire consumption, those of the iron-cored and air-cored models are 95.3 m and 815.6 m, respectively. So the wire usage can be reduced to about 88 % by using iron core. However, in terms of torque characteristics, the torque ripple of the iron-cored model is about twice as large as that of the air-cored model, which may be a disadvantage on vibration and acoustic noise.","PeriodicalId":20758,"journal":{"name":"Progress in Superconductivity and Cryogenics","volume":"22 1","pages":"38-43"},"PeriodicalIF":0.3,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44785764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.9714/PSAC.2020.22.2.021
C. Song, J. Oh, Y. Ko, J. M. Lee, W. Kang, B. Kang
{"title":"Enhanced flux pinning property of GdBa 2 Cu 3 O 7-x films by ferromagnetic surface decoration","authors":"C. Song, J. Oh, Y. Ko, J. M. Lee, W. Kang, B. Kang","doi":"10.9714/PSAC.2020.22.2.021","DOIUrl":"https://doi.org/10.9714/PSAC.2020.22.2.021","url":null,"abstract":"","PeriodicalId":20758,"journal":{"name":"Progress in Superconductivity and Cryogenics","volume":"22 1","pages":"21-25"},"PeriodicalIF":0.3,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71376566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.9714/PSAC.2020.22.1.007
Dongmin Kim, Sung-Kyu Kim, Jeonwook Cho, Seokho Kim
As demand for electricity in urban areas increases, it is necessary to improve electric power stability by interconnecting neighboring substations and high temperature superconductor (HTS) power cables are considered as a promising option due to its large power capacity. However, the interconnection of substations reduces grid impedance and expected fault current is over 45 kA, which exceeds the capacity of a circuit breaker in Korean grid. To reduce the fault current below 45 kA, a HTS power cable having a fault current limiting (FCL) function is considered by as a feasible solution for the interconnection of substations. In this study, a FCL HTS power cable of 600 MVA/154 kV, transmission level class, is considered to reduce the fault current from 63 kA to less than 45 kA by generating an impedance over 1 Ωwhen the fault current is induced. For the thermal design of FCL HTS power cable, a parametric study is conducted to meet a required temperature limit and impedance by modifying the cable core from usual HTS power cables which are designed to bypass the fault current through cable former. The analysis results give a minimum cable length and an area of stainless steel former to suppress the temperature of cable below a design limit.
{"title":"Design of HTS power cable with fault current limiting function","authors":"Dongmin Kim, Sung-Kyu Kim, Jeonwook Cho, Seokho Kim","doi":"10.9714/PSAC.2020.22.1.007","DOIUrl":"https://doi.org/10.9714/PSAC.2020.22.1.007","url":null,"abstract":"As demand for electricity in urban areas increases, it is necessary to improve electric power stability by interconnecting neighboring substations and high temperature superconductor (HTS) power cables are considered as a promising option due to its large power capacity. However, the interconnection of substations reduces grid impedance and expected fault current is over 45 kA, which exceeds the capacity of a circuit breaker in Korean grid. To reduce the fault current below 45 kA, a HTS power cable having a fault current limiting (FCL) function is considered by as a feasible solution for the interconnection of substations. In this study, a FCL HTS power cable of 600 MVA/154 kV, transmission level class, is considered to reduce the fault current from 63 kA to less than 45 kA by generating an impedance over 1 Ωwhen the fault current is induced. For the thermal design of FCL HTS power cable, a parametric study is conducted to meet a required temperature limit and impedance by modifying the cable core from usual HTS power cables which are designed to bypass the fault current through cable former. The analysis results give a minimum cable length and an area of stainless steel former to suppress the temperature of cable below a design limit.","PeriodicalId":20758,"journal":{"name":"Progress in Superconductivity and Cryogenics","volume":"22 1","pages":"7-11"},"PeriodicalIF":0.3,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71376562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.9714/PSAC.2020.22.2.026
Dong Gun Lee, Jun Hyuk Choi, D. Kim, Ju Heum Jeon, M. Maeda, Seyong Choi, Jung Ho Kim
{"title":"Commercial MgB 2 superconducting wires at Sam Dong","authors":"Dong Gun Lee, Jun Hyuk Choi, D. Kim, Ju Heum Jeon, M. Maeda, Seyong Choi, Jung Ho Kim","doi":"10.9714/PSAC.2020.22.2.026","DOIUrl":"https://doi.org/10.9714/PSAC.2020.22.2.026","url":null,"abstract":"","PeriodicalId":20758,"journal":{"name":"Progress in Superconductivity and Cryogenics","volume":"22 1","pages":"26-31"},"PeriodicalIF":0.3,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71376569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.9714/PSAC.2020.22.2.032
Jun Hyuk Choi, Dong Gun Lee, D. Kim, G. Yoon, Ju Heum Jeon
{"title":"Overview of MgB 2 superconducting conductors at Sam Dong in Korea","authors":"Jun Hyuk Choi, Dong Gun Lee, D. Kim, G. Yoon, Ju Heum Jeon","doi":"10.9714/PSAC.2020.22.2.032","DOIUrl":"https://doi.org/10.9714/PSAC.2020.22.2.032","url":null,"abstract":"","PeriodicalId":20758,"journal":{"name":"Progress in Superconductivity and Cryogenics","volume":"22 1","pages":"32-37"},"PeriodicalIF":0.3,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71376573","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.9714/PSAC.2020.22.4.031
S. Fetisov, V. Zubko, A. Nosov, S. Zanegin, V. Vysotsky
{"title":"Review of the design, production and tests of compact AC HTS power cables","authors":"S. Fetisov, V. Zubko, A. Nosov, S. Zanegin, V. Vysotsky","doi":"10.9714/PSAC.2020.22.4.031","DOIUrl":"https://doi.org/10.9714/PSAC.2020.22.4.031","url":null,"abstract":"","PeriodicalId":20758,"journal":{"name":"Progress in Superconductivity and Cryogenics","volume":"22 1","pages":"31-39"},"PeriodicalIF":0.3,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71376580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.9714/PSAC.2020.22.1.001
Yi-Seul Hong, Chan-Joong Kim, H. Lee
{"title":"A parameter study on the pre-heat treatment for the fabrication of a large grain YBCO bulk superconductor without intermediate grinding step","authors":"Yi-Seul Hong, Chan-Joong Kim, H. Lee","doi":"10.9714/PSAC.2020.22.1.001","DOIUrl":"https://doi.org/10.9714/PSAC.2020.22.1.001","url":null,"abstract":"","PeriodicalId":20758,"journal":{"name":"Progress in Superconductivity and Cryogenics","volume":"14 1","pages":"1-6"},"PeriodicalIF":0.3,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71376558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.9714/PSAC.2020.22.3.020
Yejun Yang, Taejin Park, D. Kwon, Lingxue Jin, Sangkwon Jeong
The purpose of this analytic study is to design and examine an efficient hydrogen liquefaction cycle by using a pre-cooler. The liquefaction cycle is primarily comprised of a pre-cooler and a refrigerator. The fed hydrogen gas is cooled down from ambient temperature (300 K) to the pre-cooling coolant temperature (either 77 K or 120 K approximately) through the pre-cooler. There are two pre-cooling methods: a single pre-coolant pre-cooler and a cascade pre-cooler which uses two levels of pre-coolants. After heat exchanging with the pre-cooler, the hydrogen gas is further cooled and finally liquefied through the refrigerator. The working fluids of the potential pre-cooling cycle are selected as liquid nitrogen and liquefied natural gas. A commercial software Aspen HYSYS is utilized to perform the numerical simulation of the proposed liquefaction cycle. Efficiency is compared with respect to the various conditions of the heat exchanging part of the pre-cooler. The analysis results show that the cascade method is more efficient, and the heat exchanging part of the pre-coolers should have specific UA ratios to maximize both spatial and energy efficiencies. This paper presents the quantitative performance of the pre-cooler in the hydrogen liquefaction cycle in detail, which shall be useful for designing an energy-efficient liquefaction system.
{"title":"Effectiveness analysis of pre-cooling methods on hydrogen liquefaction process","authors":"Yejun Yang, Taejin Park, D. Kwon, Lingxue Jin, Sangkwon Jeong","doi":"10.9714/PSAC.2020.22.3.020","DOIUrl":"https://doi.org/10.9714/PSAC.2020.22.3.020","url":null,"abstract":"The purpose of this analytic study is to design and examine an efficient hydrogen liquefaction cycle by using a pre-cooler. The liquefaction cycle is primarily comprised of a pre-cooler and a refrigerator. The fed hydrogen gas is cooled down from ambient temperature (300 K) to the pre-cooling coolant temperature (either 77 K or 120 K approximately) through the pre-cooler. There are two pre-cooling methods: a single pre-coolant pre-cooler and a cascade pre-cooler which uses two levels of pre-coolants. After heat exchanging with the pre-cooler, the hydrogen gas is further cooled and finally liquefied through the refrigerator. The working fluids of the potential pre-cooling cycle are selected as liquid nitrogen and liquefied natural gas. A commercial software Aspen HYSYS is utilized to perform the numerical simulation of the proposed liquefaction cycle. Efficiency is compared with respect to the various conditions of the heat exchanging part of the pre-cooler. The analysis results show that the cascade method is more efficient, and the heat exchanging part of the pre-coolers should have specific UA ratios to maximize both spatial and energy efficiencies. This paper presents the quantitative performance of the pre-cooler in the hydrogen liquefaction cycle in detail, which shall be useful for designing an energy-efficient liquefaction system.","PeriodicalId":20758,"journal":{"name":"Progress in Superconductivity and Cryogenics","volume":"22 1","pages":"20-24"},"PeriodicalIF":0.3,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71376576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-12-01DOI: 10.9714/PSAC.2019.21.4.006
Younsik Kim, S. Huh, Jonghyuk Kim, Y. Choi, Changyoung Kim
Iron-based superconductors (IBSs) possess nematic phases in which rotational symmetry of the electronic structure is spontaneously broken. This novel phase has attracted much attention as it is believed to be closely linked to the superconductivity. However, observation of the symmetry broken phase by using a macroscopic experimental tool is a hard task because of naturally formed twin domains. Here, we report on a novel detwinning method by using a magnetic field on FeTe single crystal. Detwinning effect was measured by resistivity anisotropy using the Montgomery method. Our results show that FeTe was detwinned at 2T, which is a relatively weak field compared to the previously reported result. Furthermore, detwinning effect is retained even when the field is turned off after field cooling, making it an external stimulation-free detwinning method.
{"title":"Magnetic field detwinning in FeTe","authors":"Younsik Kim, S. Huh, Jonghyuk Kim, Y. Choi, Changyoung Kim","doi":"10.9714/PSAC.2019.21.4.006","DOIUrl":"https://doi.org/10.9714/PSAC.2019.21.4.006","url":null,"abstract":"Iron-based superconductors (IBSs) possess nematic phases in which rotational symmetry of the electronic structure is spontaneously broken. This novel phase has attracted much attention as it is believed to be closely linked to the superconductivity. However, observation of the symmetry broken phase by using a macroscopic experimental tool is a hard task because of naturally formed twin domains. Here, we report on a novel detwinning method by using a magnetic field on FeTe single crystal. Detwinning effect was measured by resistivity anisotropy using the Montgomery method. Our results show that FeTe was detwinned at 2T, which is a relatively weak field compared to the previously reported result. Furthermore, detwinning effect is retained even when the field is turned off after field cooling, making it an external stimulation-free detwinning method.","PeriodicalId":20758,"journal":{"name":"Progress in Superconductivity and Cryogenics","volume":"21 1","pages":"6-8"},"PeriodicalIF":0.3,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44581506","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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