Details of a Researcher - SAKODA Tatsuya

Papers - SAKODA Tatsuya

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Visualization and Diagnosis Method of Defective Photovoltaic String Based on the Temporal Variation Characteristics of String Currents in Generation Mode Reviewed

TORIHARA Ryo, KODAMA Takafumi, TAKENOUCHI Osamu, SAKODA Tatsuya, HAYASHI Noriyuki

Journal of Japan Solar Energy Society 47 ( 3 ) 27 - 36 2021.5

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Solar Energy Society

DOI： 10.24632/jses.47.3_27

CiNii Research

Influence of defective bypass diodes on electrical and thermal properties of photovoltaic string and array

Torihara R., Latt N.Z., Khin M.O., Lwin Y.M., Sakoda T., Hayashi N.

IEEE Region 10 Annual International Conference, Proceedings/TENCON 2020-November 1007 - 1012 2020.11

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：IEEE Region 10 Annual International Conference, Proceedings/TENCON

The intent of this paper is to analyze the power consumption or heat dissipation of defective bypass diode (BPD) at open circuit (OC) and maximum power point (MPP) load conditions when the BPD turns to have resistive behavior in a photovoltaic (PV) string and array. We also analyze the thermal impact of defective BPD in a PV string under different irradiances and cell temperatures. It was observed that the power consumption of defective BPD largely depends on load condition and the thermal impact is more severe in OC condition. It was also observed that the thermal impact of defective BPD is larger under either high irradiance level for the same cell temperature or lower cell temperature on the same irradiance. This study indicates that it is necessary to monitor the heat dissipation of BPDs and to evaluate the electrical properties of the BPDs to realize the reliable PV systems.

DOI： 10.1109/TENCON50793.2020.9293827

Scopus

On-line PD System and PD Locator for XLPE Cables

Sakoda T., Yamasaki Y., Nakanose S., Hayashi N., Miyake T., Miyagawa K., Kawano W.

Proceeding - 8th International Conference on Condition Monitoring and Diagnosis, CMD 2020 222 - 225 2020.10

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Proceeding - 8th International Conference on Condition Monitoring and Diagnosis, CMD 2020

We constructed an on-line partial discharge (PD) monitoring system (PDOM) with a CT sensor, an analogue-digital converter, and a tablet PC. A sampling frequency for data acquisition is 100 MHz, and we exchange on-site PD data through a cloud system. We successfully measured PDs in the early stage of insulation deterioration of a cross-linked polyethylene (XLPE) cable in a field site. Additionally, following PD detection by using a PDOM, we can locate a PD position by using a PD locator (PDL) system. By locating a PD, we can estimate the actual PD magnitude considering attenuation factor of a high frequency pulse. We show how the PDL system works on a XLPE cable network with time synchronization between two positions by using an injection current pulse. The locating accuracy of the PDL system is evaluated.

DOI： 10.1109/CMD48350.2020.9287182

Scopus

On-line PD system and PD Locator for XLPE Cables Reviewed

Tatsuya Sakoda, Noriyuki Hayashi, Yuhei Yamasaki, Soichiro Nakanose, Takuma Miyake, Wataru Kawano, Koji Miyagawa

8th International Conference on Condition Monitoring and Diagnosis 1 - 4 2020.10

Language：English Publishing type：Research paper (international conference proceedings)

Affecting Factors to V-t Characteristics of Impulse Discharge Reviewed

Oda Hiroshi, Hazama Issei, Sakoda Tatsuya, Kubo Katsutaka, Mizutani Manabu, Kasuga Yasunori, Fukano Takato

Memoirs of Faculty of Engineering, University of Miyazaki 49 111 - 114 2020.9

Language：Japanese Publishing type：Research paper (scientific journal)

CiNii Research

Study on degradation diagnostic method for silicone rubber

Sakoda T., Minami E., Miyake T., Hayashi N., Goto S., Aka Y., Anjiki T., Kasuga Y., Fukano T.

Journal of Electrostatics 107 2020.9

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Journal of Electrostatics

To evaluate the degradation degree of silicone rubber (SiR) of electric power apparatus arranged for a long period of time in the coastal area, we repeatedly performed a salt fog aging test against SiR specimens. Then, the surface hydrophobicity and the leakage current were evaluated. The results showed that a required time for recovering hydrophobicity and a discharge ignition time until the leakage current is detectable are good indexes for degradation diagnosis. Especially, the required time for recovering hydrophobicity is useful.

DOI： 10.1016/j.elstat.2020.103479

Scopus

Multivariate Analysis Using R for Various Climatic Effects on the Output Performances of CIGS and Multi-Crystalline Si Photovoltaic Systems Installed in Miyazaki, Japan

太田靖之, 迫田達也

宮崎大学工学部紀要 49 119 - 127 2020.9

Language：English Publishing type：Research paper (bulletin of university, research institution) Publisher：宮崎大学工学部

Generally, the performance of a PV system depends not only on its basic technical characteristics but also on the environmental conditions in which they will be set up. Therefore, studying the effects of climatic parameters such as solar irradiance on the plane of array (GPOA), ambient temperature (Ta), relative humidity (RH) and wind speed (νa) on the performance of PV is vital to be able to utilize efficiently solar energy.
The authors have studied the effects of various climatic parameters on the output performances of the two PV systems, 60 kW Copper Indium Gallium Selenide (CIGS) and 50 kW Multi-Crystalline Silicon (MC-Si), which were installed within the campus of University of Miyazaki, Japan. The main objectives of the research are to improve the prediction of the PV systems performance while knowing the climatic parameters of a particular area in which they stand, and also provide a useful dataset for the comparative studies.
The analyses were done by the multiple linear regression analysis (MLR) using the statistical software R. The performances of the two PV systems are in positive proportion to the GPOA and νa, however, as per the values of the slopes of the regression equations, the MC-Si PV system is smaller than the CIGS PV system, attributed to their different module tilt angles and elevations of the PV sites. The performances are in negative proportion to the Ta, but the more sensitivity can be observed in the MC-Si PV system. The RH negatively affected on the MC-Si PV system, although its positive effects can be observed in the CIGS PV system.

CiNii Research

Study on Location Accuracy of Partial Discharge Locator for Electric Power Cable Reviewed

Yamashita Katsuya, Sakoda Tatsuya

Memoirs of Faculty of Engineering, University of Miyazaki 49 91 - 94 2020.9

Language：Japanese Publishing type：Research paper (scientific journal)

CiNii Research

Sterilization of Stem-end Rot of Mango using Dielectric Barrier Discharge Source and Influence of Operating Gas on sterilization Reviewed

Kinoshita Shunsuke, Tada Yoichiro, Sakoda Tatsuya, Tazawa Kazutoshi, Ichikawa Hiroaki, Ichikawa Hiroyuki

Memoirs of Faculty of Engineering, University of Miyazaki 49 115 - 118 2020.9

Language：Japanese Publishing type：Research paper (scientific journal)

CiNii Research

Partial Discharge Characteristics of XLPE Cable with Water Tree Reviewed

Yamashita Katsuya, Sakoda Tatsuya, Yamasaki Yuhei

Memoirs of Faculty of Engineering, University of Miyazaki 49 101 - 104 2020.9

Language：Japanese Publishing type：Research paper (scientific journal)

CiNii Research

Characteristics of Partial Discharge in Epoxy Resin with a Void Reviewed

Oda Hiroshi, Sakoda Tatsuya, Aishima Takeru, Nishimura Takeshi

Memoirs of Faculty of Engineering, University of Miyazaki 49 105 - 109 2020.9

Language：Japanese Publishing type：Research paper (scientific journal)

CiNii Research

Study on Propagation Characteristics of High Frequency Pulse Current in Electric Power Cable Reviewed

Yamashita Katsuya, Sakoda Tatsuya

Memoirs of Faculty of Engineering, University of Miyazaki 49 95 - 99 2020.9

Language：Japanese Publishing type：Research paper (scientific journal)

CiNii Research

Study on Location Accuracy of Partial Discharge Locator for Electric Power Cable

Katsuya YAMASHITA, Tatsuya SAKODA

Memoirs of Faculty of Engineering University of Miyazaki 91 - 94 2020.7