{"title":"Development of DC Deep Water Submarine Cable (Single Core Type of Water Depth 1500 m)","authors":"Yosuke Otake, Yutaka Kishida, Youngduk Yoon, Hiroyuki Sakakibara","doi":"10.1002/eej.23515","DOIUrl":"https://doi.org/10.1002/eej.23515","url":null,"abstract":"<div>\u0000 \u0000 <p>Considering optimization of the laying route for submarine power cables off the coast of Japan, there are many deepwater areas over depth of 1000 m. In Japan, submarine power cables have been installed at a depth of about 300 m as maximum; however, there is no track record beyond that level. The laying depth is deeper, the laying tension is larger. Therefore, as a result of discussion on the cable structure and material suitable for the laying in deep water, the aluminum conductor with keystone structure was applied for reducing the cable weight since the laying tension is proportional to the product of depth and weight. In this study, the prototype submarine cables of DC 500 kV class (transmission capability of 1 GW) equipped with the double steel wire armor were manufactured, then mechanical and electrical properties were evaluated in accordance with CIGRE TB 496 and TB 623. As a result, the cables of our design, on which the tensile bending test had been carried out in advance, passed the high-voltage 30 days load cycle test followed by the lightning impulse test without any defect.</p>\u0000 </div>","PeriodicalId":50550,"journal":{"name":"Electrical Engineering in Japan","volume":"218 3","pages":"3-11"},"PeriodicalIF":0.6,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145135406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Development of DC Deep Water Submarine Cable (Single Core Type of Water Depth 1500 m)","authors":"Yosuke Otake, Yutaka Kishida, Youngduk Yoon, Hiroyuki Sakakibara","doi":"10.1002/eej.23515","DOIUrl":"https://doi.org/10.1002/eej.23515","url":null,"abstract":"<div>\u0000 \u0000 <p>Considering optimization of the laying route for submarine power cables off the coast of Japan, there are many deepwater areas over depth of 1000 m. In Japan, submarine power cables have been installed at a depth of about 300 m as maximum; however, there is no track record beyond that level. The laying depth is deeper, the laying tension is larger. Therefore, as a result of discussion on the cable structure and material suitable for the laying in deep water, the aluminum conductor with keystone structure was applied for reducing the cable weight since the laying tension is proportional to the product of depth and weight. In this study, the prototype submarine cables of DC 500 kV class (transmission capability of 1 GW) equipped with the double steel wire armor were manufactured, then mechanical and electrical properties were evaluated in accordance with CIGRE TB 496 and TB 623. As a result, the cables of our design, on which the tensile bending test had been carried out in advance, passed the high-voltage 30 days load cycle test followed by the lightning impulse test without any defect.</p>\u0000 </div>","PeriodicalId":50550,"journal":{"name":"Electrical Engineering in Japan","volume":"218 3","pages":"3-11"},"PeriodicalIF":0.6,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145135401","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"An Adjustment Method for Re-Adhesion Control of Electric Rolling Stock Using Particle Swarm Optimization and its Validation by a Scale Model Railway Vehicle","authors":"Hiroki Tanji, Michihiro Yamashita, Takahiro Murakami","doi":"10.1002/eej.23522","DOIUrl":"https://doi.org/10.1002/eej.23522","url":null,"abstract":"<div>\u0000 \u0000 <p>This paper presents an algorithm for the re-adhesion control of electric rolling stocks. Generally, an engineer manually adjusts parameters used in any re-adhesion control algorithm before a commercial operation. However, it depends heavily on the experience of the engineer. Therefore, developing an automatic adjustment system for re-adhesion control is imperative. To this end, we apply the particle swarm optimization (PSO) algorithm to re-adhesion control. In our approach, a cost function based on the averaged tangential force of an electric bogie is optimized by the PSO algorithm, and the parameters for re-adhesion control are automatically adjusted. In addition, experiments using a scale model railway vehicle are carried out to validate the proposed method.</p>\u0000 </div>","PeriodicalId":50550,"journal":{"name":"Electrical Engineering in Japan","volume":"218 3","pages":"50-62"},"PeriodicalIF":0.6,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145135407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"An Adjustment Method for Re-Adhesion Control of Electric Rolling Stock Using Particle Swarm Optimization and its Validation by a Scale Model Railway Vehicle","authors":"Hiroki Tanji, Michihiro Yamashita, Takahiro Murakami","doi":"10.1002/eej.23522","DOIUrl":"https://doi.org/10.1002/eej.23522","url":null,"abstract":"<div>\u0000 \u0000 <p>This paper presents an algorithm for the re-adhesion control of electric rolling stocks. Generally, an engineer manually adjusts parameters used in any re-adhesion control algorithm before a commercial operation. However, it depends heavily on the experience of the engineer. Therefore, developing an automatic adjustment system for re-adhesion control is imperative. To this end, we apply the particle swarm optimization (PSO) algorithm to re-adhesion control. In our approach, a cost function based on the averaged tangential force of an electric bogie is optimized by the PSO algorithm, and the parameters for re-adhesion control are automatically adjusted. In addition, experiments using a scale model railway vehicle are carried out to validate the proposed method.</p>\u0000 </div>","PeriodicalId":50550,"journal":{"name":"Electrical Engineering in Japan","volume":"218 3","pages":"50-62"},"PeriodicalIF":0.6,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145135405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Development of Permanent Magnets for the Reduction of Heavy Rare Earth Elements","authors":"Tadakatsu Ohkubo","doi":"10.1002/eej.23523","DOIUrl":"https://doi.org/10.1002/eej.23523","url":null,"abstract":"<div>\u0000 \u0000 <p>We have investigated the mechanism of coercivity evolution in magnets through multi-scale microstructural characterization. On the basis of these findings, our goal is to enhance the coercivity of heavy rare-earth-lean magnets by optimizing their microstructure. We have developed several new processes and demonstrated improved magnet properties. This review article describes (1) coercivity enhancement by the eutectic alloy diffusion process, (2) the development of light rare earth magnets, and (3) the development of high electrical resistance magnets. Recently, there has been an increasing demand for highly efficient magnet development that not only improves properties but also meets multiple requirements. Accordingly, (4) data-driven methods are being employed in ongoing magnet development.</p>\u0000 </div>","PeriodicalId":50550,"journal":{"name":"Electrical Engineering in Japan","volume":"218 3","pages":"63-68"},"PeriodicalIF":0.6,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145135378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Development of Permanent Magnets for the Reduction of Heavy Rare Earth Elements","authors":"Tadakatsu Ohkubo","doi":"10.1002/eej.23523","DOIUrl":"https://doi.org/10.1002/eej.23523","url":null,"abstract":"<div>\u0000 \u0000 <p>We have investigated the mechanism of coercivity evolution in magnets through multi-scale microstructural characterization. On the basis of these findings, our goal is to enhance the coercivity of heavy rare-earth-lean magnets by optimizing their microstructure. We have developed several new processes and demonstrated improved magnet properties. This review article describes (1) coercivity enhancement by the eutectic alloy diffusion process, (2) the development of light rare earth magnets, and (3) the development of high electrical resistance magnets. Recently, there has been an increasing demand for highly efficient magnet development that not only improves properties but also meets multiple requirements. Accordingly, (4) data-driven methods are being employed in ongoing magnet development.</p>\u0000 </div>","PeriodicalId":50550,"journal":{"name":"Electrical Engineering in Japan","volume":"218 3","pages":"63-68"},"PeriodicalIF":0.6,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145135379","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Automatic Generation Method for Crew Scheduling After a Large-Scale Natural Disaster","authors":"Satoshi Kato, Jun Imaizumi, Taichi Nakahigashi","doi":"10.1002/eej.23518","DOIUrl":"https://doi.org/10.1002/eej.23518","url":null,"abstract":"<div>\u0000 \u0000 <p>When railway line sections are partially disrupted due to damage from large-scale natural disasters, it is necessary to prepare crew schedule plans for temporary timetables. In such a case, a crew schedule plan ensures that duties once assigned to crew members are not changed. As this task is time-consuming for schedule planners, an automatic crew scheduling method for supporting planners is desired. In this paper, we focus on crew scheduling following a large-scale natural disaster. The proposed algorithm is based on mathematical programming and column generation. In addition, we show the results of computational experiments based on a real disaster case, which indicate that the proposed algorithm can generate an efficient schedule plan in a short time.</p>\u0000 </div>","PeriodicalId":50550,"journal":{"name":"Electrical Engineering in Japan","volume":"218 3","pages":"28-40"},"PeriodicalIF":0.6,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145135358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Automatic Generation Method for Crew Scheduling After a Large-Scale Natural Disaster","authors":"Satoshi Kato, Jun Imaizumi, Taichi Nakahigashi","doi":"10.1002/eej.23518","DOIUrl":"https://doi.org/10.1002/eej.23518","url":null,"abstract":"<div>\u0000 \u0000 <p>When railway line sections are partially disrupted due to damage from large-scale natural disasters, it is necessary to prepare crew schedule plans for temporary timetables. In such a case, a crew schedule plan ensures that duties once assigned to crew members are not changed. As this task is time-consuming for schedule planners, an automatic crew scheduling method for supporting planners is desired. In this paper, we focus on crew scheduling following a large-scale natural disaster. The proposed algorithm is based on mathematical programming and column generation. In addition, we show the results of computational experiments based on a real disaster case, which indicate that the proposed algorithm can generate an efficient schedule plan in a short time.</p>\u0000 </div>","PeriodicalId":50550,"journal":{"name":"Electrical Engineering in Japan","volume":"218 3","pages":"28-40"},"PeriodicalIF":0.6,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145135357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Proposal and Verification of a Novel Doubly-Excited Variable-Flux Consequent Pole Motor","authors":"Keito Yokota, Yoshiki Matsushita, Hiroshi Mitsuda, Tadashi Fukami, Masato Koyama, Toshinori Tanaka","doi":"10.1002/eej.23520","DOIUrl":"https://doi.org/10.1002/eej.23520","url":null,"abstract":"<div>\u0000 \u0000 <p>In this study, we propose a new type of hybrid excited motor called “doubly-excited variable-flux consequent pole motor (DeVFCM).” The DeVFCM consists of a three-phase double Y-connected armature winding with two neutral points, O<sub>1</sub> and O<sub>2</sub>, and field poles with alternating permanent magnet and iron poles. When a DC voltage for supplying the field current is applied across O<sub>1</sub> and O<sub>2</sub> in such a configuration, the armature winding also acts as a field winding, and the magnetic flux through the iron poles can be adjusted. To validate the principle of this DeVFCM, a prototype machine was fabricated, and the basic characteristics of the prototype machine were investigated through three-dimensional finite element analysis and experiments. The results show that both high torque generation and loss reduction at high speeds can be achieved by adjusting the field current.</p>\u0000 </div>","PeriodicalId":50550,"journal":{"name":"Electrical Engineering in Japan","volume":"218 3","pages":"41-49"},"PeriodicalIF":0.6,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145135263","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Proposal and Verification of a Novel Doubly-Excited Variable-Flux Consequent Pole Motor","authors":"Keito Yokota, Yoshiki Matsushita, Hiroshi Mitsuda, Tadashi Fukami, Masato Koyama, Toshinori Tanaka","doi":"10.1002/eej.23520","DOIUrl":"https://doi.org/10.1002/eej.23520","url":null,"abstract":"<div>\u0000 \u0000 <p>In this study, we propose a new type of hybrid excited motor called “doubly-excited variable-flux consequent pole motor (DeVFCM).” The DeVFCM consists of a three-phase double Y-connected armature winding with two neutral points, O<sub>1</sub> and O<sub>2</sub>, and field poles with alternating permanent magnet and iron poles. When a DC voltage for supplying the field current is applied across O<sub>1</sub> and O<sub>2</sub> in such a configuration, the armature winding also acts as a field winding, and the magnetic flux through the iron poles can be adjusted. To validate the principle of this DeVFCM, a prototype machine was fabricated, and the basic characteristics of the prototype machine were investigated through three-dimensional finite element analysis and experiments. The results show that both high torque generation and loss reduction at high speeds can be achieved by adjusting the field current.</p>\u0000 </div>","PeriodicalId":50550,"journal":{"name":"Electrical Engineering in Japan","volume":"218 3","pages":"41-49"},"PeriodicalIF":0.6,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145135261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}