研究者詳細 - 小迫　雅裕

論文 - 小迫　雅裕

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Impedance Network Modeling of non-linear Restistive Material 査読有り

G.Belijar, L.Hermette, M.Kozako, M.Hikita

International Conference on Dielectrics (ICD2018) ( 203 ) 2018年07月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Hungary Budapest 2018年07月01日 - 2018年07月05日

© 2018 IEEE. Advances in high voltage / high power density apparatus is required for the energy transition challenge. Facing this challenge of intense electrical constraint, non-linear resistive materials are valuable to perform functions such as field grading or surge protection. If great advances have been made regarding these materials, some effort are still necessary on simulating their behavior. In this article, an impedance network modelling method is presented to simulate the response of epoxy/zinc oxide composite.

DOI： 10.1109/ICD.2018.8468501

Scopus

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Partial Discharge Inception Voltage of Enameled Cellular Wire under Impulse Voltage 査読有り

K.Maeda, T.Kubo, T.Uchimura, H.Mizoguchi, M.Kozako, M.Hikita, D.Mutou, K.Tomizawa, K.Ikeda

International Conference on Dielectrics (ICD2018) ( 3 ) 2018年07月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Hungary Budapest 2018年07月01日 - 2018年07月05日

© 2018 IEEE. In order to suppress partial discharge (PD) generated in the wedge gap between an inverter drive motor windings due to overvoltage, the authors have developed a low permittivity film with micro cellular in an insulating layer resin. An attempt is made to measure partial discharge inception voltage (PDIV) for twisted pair sample of insulating film with micro cellular in the resin. This paper deals with experimental and analytical investigation on improved PDIV owing to micro cavities in the insulating layer under AC and impulse voltage application. Measured PDIV under AC and impulse voltage application is interpreted quantitatively in terms of Volume-Time theory which considers the generation probability of initial electrons supplied from both the solid insulating material surface and the wedge gap volume as well as a streamer inception criterion.

DOI： 10.1109/ICD.2018.8470057

Scopus

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Influence of Electromagnetic Sensor Location on Repetitive Partial Discharge Inception Voltage in Actual Stator Core of Inverter Fed Motor 査読有り

M.Hikita, H.Mizoguchi, T.Kubo, T.Uchimura, M.Kozako, J.Sun, A.Izumi, K.Karasawa, T.Hirose, T.Ueno, S.Hiroshima

2018 IEEE Electrical Insulation Conference (EIC2018) 435 - 438 2018年06月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

USA San Antonio 2018年06月17日 - 2018年06月20日

© 2018 IEEE. Repetitive partial discharge inception voltage (RPDIV) measurement is indispensable for inverter-fed motor when testing the insulation dignity according to IEC 60034-18-41 IS. Our previous study showed detection sensitivity comparison among kinds of electromagnetic (EM) sensors for PD measurement in an actual motor core. This paper deals with an influence of the location of EM sensors on the sensitivity of detected EM wave to quantitatively evaluate RPDIV. As a result, it was found that employing the EM wave sensor located at the furthest position from the PD source on Z axis to detect PD can result in estimating higher RPDIV by 7.5 % at most than an actual one, depending on the sensor location. The possibility of location of a PD source using multiple LSs placed in the actual core is also suggested from differences in the signal strength and time for EM signal to reach multiple LSs.

DOI： 10.1109/EIC.2018.8481091

Scopus

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Properties of thermally aged natural esters used as insulating liquid 査読有り

A.Rajab, M.Tsuchie, M.Kozako, M.Hikita, T.Suzuki

International Journal on Electrical Engineering and Informatics 10 ( 2 ) 220 - 231 2018年06月

記述言語：英語掲載種別：研究論文（学術雑誌）

© 2018, School of Electrical Engineering and Informatics. All rights reserved. An accelerated aging test is an important test to assess a long time performance of an insulation system. This paper deals with the investigation results on thermally aged natural esters insulating liquid used for transformator. Two kinds of monoesters, palm fatty acid ester (PFAE) and stearic/oleic/linoleic acids methyl esters (M182), and one tri-ester, Envirotemp (FR3), were aged at the temperature of 120°C for 60 days. An as-received oil was used as a sample for aging test, so that the presence of a limited amount of air, and thus oxygen, in oil sample could not be avoided. The important properties like appearance, moisture content, acid value, volume resistivity, and breakdown voltage are evaluated at each 15 days interval. Experiment on mineral oil under the same condition was also conducted for comparison. It was observed that the color of the FR3 was changed from light-green to dark-green. PFAE, M182 and mineral oils which were initially transparent became yellow-green, light yellow and brown, respectively. A sludge formation was observed in the mineral oil, whereas the increase in acidity was found in the PFAE and M182 oils. The moisture content of aged PFAE and M182 oils decreased whereas that of aged FR3 and mineral oils increased. The volume resistivity of all tested oils decreased with aging time, whereas their breakdown voltage showed a different behaviours. The breakdown voltage of M182 and mineral oils increased and decreased, respectively, whereas that of PFAE and FR3 relatively unchanged.

DOI： 10.15676/ijeei.2018.10.2.2

Scopus

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PD behaviors of monoester insulating oil under different moisture contents 査読有り

A.Rajab, M.Tsuchie, M.Kozako, M.Hikita, T.Suzuki

Telkomnika (Telecommunication Computing Electronics and Control) 16 ( 2 ) 481 - 487 2018年04月

記述言語：英語掲載種別：研究論文（学術雑誌）

© 2018 Universitas Ahmad Dahlan. One of the problems encounters in implementing vegetable oils (natural esters) as a transformer insulating oil is their viscosity which is high. To address this problem, monoester derived from vegetable oil was introduced. This paper deals with partial discharge (PD) behaviors of dry and moist samples of a monoester type insulating oil, palm fatty acid ester (PFAE), under AC high voltage utilizing a needle plane electrode configuration. Variations of average PD charge and PD number against the variation of voltage application, as well as their polarity discrimination under both dry and moist sample conditions are analyzed. PD pulses phase distributions of both dry and moist sample oils are elaborated. Finally, a mechanism of the water molecules effect on PD behavior is proposed based on experimental results and shown schematically.

DOI： 10.12928/TELKOMNIKA.v16i2.7356

Scopus

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Simulation of Electrical Characteristics for Misalignment of Coil in Wireless Power Transfer System Using Repeating Coil 査読有り

A.Imakiire, H.Tokunaga, A.Kawagoe, M.Kozako, M.Hikita

The 6th IIAE International Conference on Industrial Application Engineering 2018( ICIAE2018) ( 18 ) 81 - 88 2018年03月

Novel Partial Discharge Location Algorithm for Next Generation Power Module using Small Loop Sensors 査読有り

J.Maki, Y.Akinaga, M.Kozako, M.Hikita, Y.Nakamura, K.Taniguchi, Y.Ikeda, K.Okamoto

10th International Conference on Integrated Power Electronics Systems(CIPS) ( P2.12 ) 186 - 191 2018年03月

Dielectric Properties and Partial Discharge Inception Voltage of Aluminum Nitride Insulating Substrate at High Temperatures 査読有り

T.Abe, M.Suenaga, A.Imakiire, M.Kozako, M.Hikita, H.Shiota, T.Nishimura, H.Muto

10th International Conference on Integrated Power Electronics Systems(CIPS) ( P2.6 ) 155 - 160 2018年03月

Thermal Characteristic Evaluation and Transient Thermal Analysis of Next-generation SiC Power Module at 250 °C 査読有り

A.Imakiire, M.Kozako, M.Hikita, K.Tatsumi, M.Inagaki, T.Iizuka, H.Narimatsu, N.Sato, K.Shimizu, K.Ueda, K.Sugiura, K.Tsuruta, M.Iida, K.Toda

10th International Conference on Integrated Power Electronics Systems(CIPS) ( P2.9 ) 174 - 179 2018年03月

Aging properties of monoesters and comparison with tri-ester and mineral oil 査読有り

Rajab A., Tsuchie M., Kozako M., Hikita M., Suzuki T.

2017 IEEE 19th International Conference on Dielectric Liquids, ICDL 2017 2017-January 1 - 4 2017年11月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Two types of esters derived from vegetable oil, triglyceride (tri-ester) and monoester, have been implemented as insulation in the oil filled transformer. Tri-ester type is superior in flash point but inferior in viscosity and pour point compared to the monoester type. An accelerated aging test is an important test to assess a long time performance of an insulation system. Two kinds of monoesters, palm fatty acid ester (PFAE) and stearic/oleic/linoleic acids methyl esters (M182), and one tri-ester, Envirotemp (FR3), were thermally aged at the temperature of 120 °C for 60 days. The aging test was performed with the presence of a limited amount of air in oil sample by using as-received oil. The important properties like breakdown voltage, resistivity, and moisture content are evaluated at each 15 days interval. Experiment on mineral oil under the same condition was also conducted for comparison.

DOI： 10.1109/ICDL.2017.8124718

Scopus

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量子化学計算を用いた炭化水素系熱硬化性樹脂の誘電率推定の検討査読有り

渕裕樹, 中迫椋太, 小迫雅裕, 匹田政幸, 亀井伸人

電気学会論文誌A 137 ( 11 ) 626 - 631 2017年11月

記述言語：日本語掲載種別：研究論文（学術雑誌）

© 2017 The Institute of Electrical Engineers of Japan. In recent years, understanding of the characteristic mechanism of electrical insulating materials using quantum chemical calculation has attracted increasing interest. Dielectric properties are one of the important properties in practical use of electrical insulating materials, but there is no precedent investigation for the dielectric properties using quantum chemical calculation. In this paper, the relative permittivity of dicyclopentadiene and tricyclopentadiene resin is estimated by mean of density functional theory and Clausius-Mossotti's, Onsager's or Kirkwood's equations. As a result, estimated values of the relative permittivity are in reasonable agreement with experimental ones. In addition, in order to investigate the dependency of estimated values on molecular modeling, the influence of the number of repeating units was examined. As a result, it was found that the estimated values is almost independent of the number of repeating units. In other words, the calculation model for the permittivity prediction may be sufficient for a small molecular chain as dealt with in this paper.

DOI： 10.1541/ieejfms.137.626

Scopus

CiNii Article

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PD Pattern of Various Defects measured by TEV sensor 査読有り

H.Prasetia, U.Khayam, Suwarno, A.Itose, M.Kozako, M.Hikita

International Conference on High Voltage Engineering and Power Systems (ICHVEPS2017) ( TS1-3 ) 12 - 17 2017年10月

Basic study on measurement of electromagnetic waves emitted by partial discharge in cable joint for high voltage overhead transmission 査読有り

S.Masuda,T.Koga, M.Kozako, M.Hikita, H.Haruyama, I.Kato, H.Sato, F.Aono

2017 International Symposium on Electrical Insulating Materials (ISEIM2017) 2 547 - 550 2017年09月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Japan Toyohashi 2017年09月11日 - 2017年09月15日

© 2017 Institute of Electrical Engineers of Japan. All rights reserved. Insulation failure may occur due to aging in cable joint for high voltage overhead transmission. From the view point, this paper deals with the insulation diagnostics by measuring electromagnetic (EM) waves emitted by partial discharge (PD), which is precursory phenomenon of dielectric breakdown. The intensity and frequency spectra of PD radiated EM wave were measured with three different monopole antennas (MA) in three different frequency bands and a high frequency current transformer as a function of the distance between the antenna and PD source located in the cable joint. Experimental results revealed that difference in the arrival time between two MAs was estimated by changing the distance ? d of the three MAs located at 300, 600, and 900mm. It elucidated that the distance dependence of the PD signal can be acquired by the MA, and the method using the multi MAs provides an insight into diagnostics at the insulation failure in the cable joint.

DOI： 10.23919/ISEIM.2017.8166547

Scopus

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Comparison of insulation characteristics in electrode system with silica filled hydrocarbon-based thermosetting resin 査読有り

Y.Okubo, Y.Fuchi, R.Nakasako, M.Kozako, M.Hikita, N.Kamei

2017 International Symposium on Electrical Insulating Materials (ISEIM2017) 2 532 - 534 2017年09月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Japan Toyohashi 2017年09月11日 - 2017年09月15日

© 2017 Institute of Electrical Engineers of Japan. All rights reserved. In order to meet the demand for further high temperature operation and withstand voltage against electric insulating materials, the authors focus on Tricyclopentadiene (TCP) and Dicyclopentadiene (DCP) resins, which belong to hydrocarbon thermosetting resins. We have reported that TCP resin has lower dielectric constant and lower dielectric loss factor while having higher heat resistance than conventional epoxy resin. Our previous report revealed that insulation characteristics of TCP resin with molding the high voltage electrode depend on the interface state between the electrode and the resin. From the viewpoints, this report presents investigation of inherent insulation performance (electric breakdown strength) of the TCP resin using recessed type specimen.

DOI： 10.23919/ISEIM.2017.8166543

Scopus

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Digest Report of Investigating R&D Committee on Advancing Tailor-made Composite Insulation Materials 査読有り

T.Tanaka, M.Kozako, T.Imai, M.Kurimoto

2017 International Symposium on Electrical Insulating Materials (ISEIM2017) ( DR-5 ) xiv 2017年09月

Digest Report of Cooperative Research Committee on EINA Magazine 査読有り

M.nagao, Y.Inoue, M.kozako

2017 International Symposium on Electrical Insulating Materials (ISEIM2017) ( DR-1 ) x 2017年09月

Repetitive Impulse Voltage Supply and Automatic RPDIV Measuring System 査読有り

K.Umezu, A.Takeshita, M.Hikita, M.Kozako, T.Ueno

2017 International Symposium on Electrical Insulating Materials (ISEIM2017) ( DM-7 ) 794 - 795 2017年09月

The influence of switching impulse voltage superimposition on partial discharge characteristics of oil impregnated paper insulation system and conditions inside its oil gap defect 査読有り

Y.Iwashita, A.Tokudome, N.Yamaguchi, Y.Makino, T.Kurihara, T.Takahashi, M.kozako, M.hikita

2017 International Symposium on Electrical Insulating Materials (ISEIM2017) 1 399 - 402 2017年09月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Japan Toyohashi 2017年09月11日 - 2017年09月15日

The authors have evaluated the possibility of deterioration diagnosis of Oil-filled (OF) cable systems by PD measurement so far. In our previous studies, we confirmed continuous occurrence of PDs even under the design electric field of 275 kY OF cables. Also we confirmed the progress of intermittent occurrence of PDs to continuous one by repeated superimpositions of lightning impulse voltage corresponding to switching surge. However, correlation between PD characteristics and internal conditions of the oil gap defect was not obtained. Therefore, in this study, we experimentally investigated the effects of the switching impulse voltage superimposition that can occur in practical operation of 275 OF cable systems on PD characteristics and we observed the conditions inside the oil gap defect by a CCD camera.

Scopus

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Sensitivity characteristics of partial discharge electromagnetic sensor located in stator core 査読有り

T.Kubo, T.Uchimura, M.Kozako, M.Hikita, T.Ueno, J.Sun, A.Izumi, K.Karasawa, T.Hirose, S.Hiroshima

2017 International Symposium on Electrical Insulating Materials (ISEIM2017) 2 680 - 683 2017年09月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Japan Toyohashi 2017年09月11日 - 2017年09月15日

© 2017 Institute of Electrical Engineers of Japan. All rights reserved. Repetitive partial discharge inception voltage (RPDIV) measurement is indispensable for inverter-fed motor when testing according to IEC 60034-18-41 IS. Our previous study showed sensitivity comparison between kinds of electromagnetic (EM) sensors and a partial discharge (PD) measuring device in an actual motor core. This paper deals with an influence of the position and distance of EM sensor on the sensitivity of detected EM wave to quantitatively evaluate RPDIV. Results revealed that the detected signal attenuation is affected by not only the distance between the PD source and the sensor location but also the existence of the actual core. Furthermore, RPDIV provided by a loop sensor located at 135° around the circumference direction from the bottom of the core was estimated by 10% higher than that determined with a reference LS located just above the PD source which was placed at the bottom of the core. Namely, it is indicated that employing EM wave sensor to detect PD can result in estimating higher RPDIV than actual one. In other words, a correction is necessary for estimating precise RPDIV by multiplying a given factor depending on the size of the core and the location of the EM sensor to measure RPDIV.

DOI： 10.23919/ISEIM.2017.8166582

Scopus

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Propagation characteristics of acoustic wave induced by partial discharge in IGBT module 査読有り

J.Maki, Y.Akinaga, M.kozako, M.Hikita, Y.Nakamura, K.Taniguchi, Y.Ikeda, K.Okamoto

2017 International Symposium on Electrical Insulating Materials (ISEIM2017) 2 668 - 671 2017年09月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Japan Toyohashi 2017年09月11日 - 2017年09月15日

© 2017 Institute of Electrical Engineers of Japan. All rights reserved. The next-generation power module is expected to be used in high voltage applications. The key issue in high-voltage power module is the existence of partial discharge (PD). Therefore identifying a PD location leads to a higher voltage operation of power module. PD location could be made by measuring acoustic wave detected by acoustic emission sensors. This paper deals with propagation characteristics of acoustic wave emitted by PD in an IGBT power module.

DOI： 10.23919/ISEIM.2017.8166579

Scopus

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