Takahiro Nakamura - IEEE Xplore Author Profile
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Takahiro Nakamura

Also published under: T. Nakamura

Publications
15
Citations
93
Publications by Year
20152021
Co-Authors:
Show All Co-Authors (32)
Image of author Takahiro Nakamura

Takahiro Nakamura

Also published under: T. Nakamura

Affiliation

Insulation Center
Toshiba Mitsubishi-Electric Industrial Systems Corporation
Tsurumi-ku, Yokohama, Japan

Publication Topics

Biography

Takahiro Nakamura received the B.eng and M. Eng and Dr. degrees in electrical engineering from the University of Tokyo in 2013, 2015, and 2018, respectively. From April 2018, he has been working for TMEIC and engaged in a research on insulation system of motor.(Based on document published on 9 February 2021).
Publications
15
Citations
93
Publications by Year
20152021
Co-Authors:
Show All Co-Authors (32)
Author's Published Works

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Power Density and Temperature Rise Estimation at End-turn Stress Grading System of Large Rotating Machines under PWM Waveform

Takahiro Umemoto;Takahiro Nakamura

IEEE Transactions on Dielectrics and Electrical Insulation
Year: 2021 | Volume: 28, Issue: 1 | Journal Article |
Cited by: Papers (2)
In this paper, the time-averaged power densities as well as the resulting temperature rise, on an end-turn stress grading (SG) system under PWM waveforms as functions of the carrier and the fundamental frequencies are systematically investigated by finite element method-based computations. A novel analytical approximation method to estimate the power densities and the temperature rises without tim...Show More

Power Density and Temperature Rise Estimation at End-turn Stress Grading System of Large Rotating Machines under PWM Waveform

Takahiro Umemoto;Takahiro Nakamura

Year: 2021 | Volume: 28, Issue: 1 | Journal Article |

Effects of Filler-size on Electrical Treeing in Epoxy/Silica Nanocomposites

S. Nakamura;A. Kumada;K. Hidaka;H. Hirai;T. Imai;T. Nakamura;Y. Ohgashi;T. Yoshimitsu

2020 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)
Year: 2020 | Conference Paper |
Cited by: Papers (1)
There has been an increasing interest in the use of nanosized fillers as additives to polymer materials (nanocomposite) because of its superior performance in dielectric strength. It is known that nano-particle size may affect tree-propagation. In order to develop reasonable nanocomposite polymer which has larger particle diameter and smaller amount of nano-particles, the effect of filler-size on ...Show More

Effects of Filler-size on Electrical Treeing in Epoxy/Silica Nanocomposites

S. Nakamura;A. Kumada;K. Hidaka;H. Hirai;T. Imai;T. Nakamura;Y. Ohgashi;T. Yoshimitsu

Year: 2020 | Conference Paper |

Proposal of Noise Rejection in Automatic Measurement System of Repetitive Partial Discharge Inception Voltage

Yasutaka Nishigaki;Sho Takenouchi;Masahiro Kozako;Masayuki Hikita;Takahiro Nakamura;Jintong Sun;Aoto Izumi;Takayuki Sakurai;Kazunari Karasawa;Tatsuya Hirose

2020 International Symposium on Electrical Insulating Materials (ISEIM)
Year: 2020 | Conference Paper |
Repetitive partial discharge inception voltage (RPDIV) measurement is necessary for inverter-fed motor when testing according to IEC 60034-18-41. Our previous study showed an influence of the position and distance of EM sensor on the sensitivity of detected EM wave to quantitatively evaluate RPDIV by using the RPDIV automatic measurement system. This paper deals with proposal of a new PDIV automat...Show More

Proposal of Noise Rejection in Automatic Measurement System of Repetitive Partial Discharge Inception Voltage

Yasutaka Nishigaki;Sho Takenouchi;Masahiro Kozako;Masayuki Hikita;Takahiro Nakamura;Jintong Sun;Aoto Izumi;Takayuki Sakurai;Kazunari Karasawa;Tatsuya Hirose

Year: 2020 | Conference Paper |

Effects of temperature on electrical treeing and partial discharges in epoxy/silica nanocomposites

Shin Nakamura;Akiko Kumada;Kunihiko Hidaka;Hiromitsu Hirai;Takahiro Imai;Takahiro Nakamura;Tetsuo Yoshimitsu

IEEE Transactions on Dielectrics and Electrical Insulation
Year: 2020 | Volume: 27, Issue: 4 | Journal Article |
Cited by: Papers (31)
This article reports the effect of temperature on tree propagation and phase resolved partial discharge (PRPD) pattern in epoxy/silica nanocomposite. The results show that tree shapes in 0-wt% and 5-wt% samples change from branch-like to bush-like as temperature rises. The tensile stress tends to decrease when the temperature is high, and a tree can select numerous paths to propagate; however, tre...Show More

Effects of temperature on electrical treeing and partial discharges in epoxy/silica nanocomposites

Shin Nakamura;Akiko Kumada;Kunihiko Hidaka;Hiromitsu Hirai;Takahiro Imai;Takahiro Nakamura;Tetsuo Yoshimitsu

Year: 2020 | Volume: 27, Issue: 4 | Journal Article |

High Temperature Partial Discharge Inception Voltage under Repetitive Impulse Voltage Applied to Motorette Samples

Yasutaka Nishigaki;Takakazu Matsuzoe;Sho Takenouchi;Masahiro Kozako;Masayuki Hikita;Takahiro Nakamura;Jintong Sun;Aoto Izumi;Takayuki Sakurai;Kazunari Karasawa;Satoshi Hiroshima

2020 IEEE Electrical Insulation Conference (EIC)
Year: 2020 | Conference Paper |
Cited by: Papers (3)
This paper presents a measurement method for partial discharge inception voltage (PDIV) and repetitive PDIV (RPDIV) of motorette samples with different terminal connections from room temperature to 155°C PDIV and RPDIV characteristics of the motorlet sample up to the high-temperature region were clarified. As a result, PDIV and RPDIV were found to decrease under high temperature environment. These...Show More

High Temperature Partial Discharge Inception Voltage under Repetitive Impulse Voltage Applied to Motorette Samples

Yasutaka Nishigaki;Takakazu Matsuzoe;Sho Takenouchi;Masahiro Kozako;Masayuki Hikita;Takahiro Nakamura;Jintong Sun;Aoto Izumi;Takayuki Sakurai;Kazunari Karasawa;Satoshi Hiroshima

Year: 2020 | Conference Paper |

Computational Approach to Electrical and Thermal behavior at End-turn Stress Grading System of Inverter-fed Rotating Machine under PWM Waveform

Takahiro Umemoto;Takahiro Nakamura;Kazunari Karasawa

2020 IEEE Electrical Insulation Conference (EIC)
Year: 2020 | Conference Paper |
Cited by: Papers (1)
SiC-based nonlinear conductive stress grading tape (SGT) has been used at an end-turn stress grading system of a form-wound rotating machine. Although previous researches reported that high-frequency repetitive pulses cause electric field enhancement and local heating at the SG system, few paper deals with the detailed electrical and thermal behaviors under pulse width modulation (PWM) waveforms, ...Show More

Computational Approach to Electrical and Thermal behavior at End-turn Stress Grading System of Inverter-fed Rotating Machine under PWM Waveform

Takahiro Umemoto;Takahiro Nakamura;Kazunari Karasawa

Year: 2020 | Conference Paper |

Fundamental and carrier frequency-dependence on electric field and power dissipation for Inverter-fed High Voltage Rotating Machine

Takahiro Nakamura;Kazunari Karasawa;Takahiro Umemoto

2020 IEEE Electrical Insulation Conference (EIC)
Year: 2020 | Conference Paper |
Cited by: Papers (2)
In this study, transient analysis of Stress Grading(SG) system under PWM waveform is conducted to reveal the effects of fundamental frequency on potential distribution and power density. Risetime, level and jump voltage of PWM waveform used in an analysis is 1μs, 3 and 5 kV, respectively. Fundamental and carrier frequencies are changed in the range from 50-500 Hz and 0.5-6 kHz, respectively. For c...Show More

Fundamental and carrier frequency-dependence on electric field and power dissipation for Inverter-fed High Voltage Rotating Machine

Takahiro Nakamura;Kazunari Karasawa;Takahiro Umemoto

Year: 2020 | Conference Paper |

Light Emission with Partial Discharge at the Stator Coil End of a Rotating Machine under Operating Temperature

Takaaki Onoda;Yuki Hasegawa;Akiko Kumada;Kunihiko Hidaka;Takahiro Umemoto;Takahiro Nakamura;Kazunari Karasawa

2020 IEEE Electrical Insulation Conference (EIC)
Year: 2020 | Conference Paper |
Cited by: Papers (2)
Electric field grading system (SG system) is introduced to prevent partial discharge at the stator coil end of a rotating machine. The SG system consists of corona armor tape (CAT) and stress grading tape/paint (SGT/SGP). The CAT is a carbon-loaded highly-conductive tape and is wound over the main insulation. A SGT/SGP is a silicon carbide powder-loaded tape/paint with field-dependent conductivity...Show More

Light Emission with Partial Discharge at the Stator Coil End of a Rotating Machine under Operating Temperature

Takaaki Onoda;Yuki Hasegawa;Akiko Kumada;Kunihiko Hidaka;Takahiro Umemoto;Takahiro Nakamura;Kazunari Karasawa

Year: 2020 | Conference Paper |

Temperature Dependence of RPDIV of Motorette Sample with Varnish Treatment

Yasutaka Nishigaki;Takakazu Matsuzoe;Tomohiro Kubo;Yusuke Nakano;Masahiro Kozako;Masayuki Hikita;Takahiro Nakamura;Jintong Sun;Aoto Izumi;Takavuki Sakurai;Kazunari Karasawa;Kenichi Nojima

2019 IEEE Electrical Insulation Conference (EIC)
Year: 2019 | Conference Paper |
Cited by: Papers (7)
Recently, driving of inverters has been advanced to improve the characteristics of motors. Along with that, concerns are raised that inverter surge deteriorates the insulation system of the motor. The problem of insulation deterioration is particularly serious in high-voltage motors where insulation structure is important, and analysis of phenomena of deterioration is strongly desired. We have mea...Show More

Temperature Dependence of RPDIV of Motorette Sample with Varnish Treatment

Yasutaka Nishigaki;Takakazu Matsuzoe;Tomohiro Kubo;Yusuke Nakano;Masahiro Kozako;Masayuki Hikita;Takahiro Nakamura;Jintong Sun;Aoto Izumi;Takavuki Sakurai;Kazunari Karasawa;Kenichi Nojima

Year: 2019 | Conference Paper |

Effects of Temperature on Electrical Treeing in Epoxy/silica Nanocomposites

S. Nakamura;A. Kumada;K. Hidaka;H. Hirai;T. Imai;T. Nakamura;T. Yoshimitsu

2019 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)
Year: 2019 | Conference Paper |
Cited by: Papers (3)
There has been an increasing interest in the use of nano- sized fillers as additives to polymer materials (nanocomposite) because of its superior performance in dielectric strength. Although most power apparatus are operated at relatively high temperature due to power dissipation in themselves, few studies have investigated the influence of temperature on an electrical tree in nanocomposite polyme...Show More

Effects of Temperature on Electrical Treeing in Epoxy/silica Nanocomposites

S. Nakamura;A. Kumada;K. Hidaka;H. Hirai;T. Imai;T. Nakamura;T. Yoshimitsu

Year: 2019 | Conference Paper |

Potential distribution on the stress grading system of high voltage rotating machines — Part II transient measurements and simulation profiles

Takahiro Nakamura;Akiko Kumada;Hisatoshi Ikeda;Kunihiko Hidaka;Yuichi Tsuboi;Tomohito Kisakibaru;Takayuki Sakurai;Tetsuo Yoshimitsu

IEEE Transactions on Dielectrics and Electrical Insulation
Year: 2019 | Volume: 26, Issue: 5 | Journal Article |
Cited by: Papers (8)
The authors developed a system that utilizes a Pockels sensor to measure the potential distribution along the stress grading (SG) system of a form wound coil. Potential distributions on a bar coil under a 50 Hz sinusoidal wave, 1 kHz rectangular wave, 1 kHz repetitive impulse, and two level pulse width modulation (PWM) voltage were measured using this system. The results are discussed using an equ...Show More

Potential distribution on the stress grading system of high voltage rotating machines — Part II transient measurements and simulation profiles

Takahiro Nakamura;Akiko Kumada;Hisatoshi Ikeda;Kunihiko Hidaka;Yuichi Tsuboi;Tomohito Kisakibaru;Takayuki Sakurai;Tetsuo Yoshimitsu

Year: 2019 | Volume: 26, Issue: 5 | Journal Article |

Tree Propagation and Partial Discharge Phenomena of Nanocomposite Epoxy

T. Nakamura;T. Yoshimitsu;T. Yokoi;A. Kumada;K. Hidaka;H. Hirai;T. Imai

2018 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP)
Year: 2018 | Conference Paper |
Cited by: Papers (12)
Tree propagation and partial discharge phenomena in nano-filled epoxy under the application of 50-Hz sinusoidal wave are studied. Silica particles whose diameters are 12 nm are filled in epoxy samples by 5 wt% and 10 wt%. Trees in a pure sample and a 5-wt% sample propagate and approach close to the grounded electrode. On the other hand, a tree in a 10-wt% sample stopped without approaching close t...Show More

Tree Propagation and Partial Discharge Phenomena of Nanocomposite Epoxy

T. Nakamura;T. Yoshimitsu;T. Yokoi;A. Kumada;K. Hidaka;H. Hirai;T. Imai

Year: 2018 | Conference Paper |

X-ray phase imaging of electrical treeing in filled epoxy

T. Nakamura;M. Tokuhiro;A. Kumada;K. Hidaka;T. Kato;T. Yamagiwa

2017 IEEE Conference on Electrical Insulation and Dielectric Phenomenon (CEIDP)
Year: 2017 | Conference Paper |
Epoxy resins are widely used as insulating material in electrical apparatus. Recently, X-ray phase imaging has a lot of attention as a method to grasp tree shape and propagation. However, observation of trees in filled epoxy is challenging because silica particles absorb X-ray and disturb the acquisition of a clear image of treeing. In this paper, image subtraction is applied to overcome this issu...Show More

X-ray phase imaging of electrical treeing in filled epoxy

T. Nakamura;M. Tokuhiro;A. Kumada;K. Hidaka;T. Kato;T. Yamagiwa

Year: 2017 | Conference Paper |

Observation of electrical treeing in epoxy resin by X-ray phase contrast imaging

Takahiro Nakamura;Kazuki Ozawa;Akiko Kumada;Kunihiko Hidaka;Tatsuro Kato;Tokio Yamagiwa

2016 IEEE International Conference on Dielectrics (ICD)
Year: 2016 | Conference Paper |
Cited by: Papers (1)
Epoxy resins are widely used as insulating material in electrical apparatus. As such epoxy resins are non-transparent due to the effect of fillers, it is hard to optically observe electrical treeing in them. In this paper, we observe electrical trees in unfilled and filled epoxy resins by X-ray phase contrast imaging. When X-ray passes through very small tubular material such as electrical trees, ...Show More

Observation of electrical treeing in epoxy resin by X-ray phase contrast imaging

Takahiro Nakamura;Kazuki Ozawa;Akiko Kumada;Kunihiko Hidaka;Tatsuro Kato;Tokio Yamagiwa

Year: 2016 | Volume: 2 | Conference Paper |

Potential distribution on the stress grading system of high-voltage rotating machines –I measuring system

Akiko Kumada;Takahiro Nakamura;Kunihiko Hidaka;Yuichi Tsuboi;Tetsuo Yoshimitsu

IEEE Transactions on Dielectrics and Electrical Insulation
Year: 2015 | Volume: 22, Issue: 6 | Journal Article |
Cited by: Papers (20)
A surface potential measuring system has been developed utilizing a Pockels sensor to measure the potential distribution of the stress grading (SG) system of form wound motor coils. A Pockels BGO crystal is positioned just above (<1 mm) the SG, and the capacitively-induced voltage on the surface of the BGO crystal adjacent to the SG is measured by using Pockels effect of the BGO crystal. The sensi...Show More

Potential distribution on the stress grading system of high-voltage rotating machines –I measuring system

Akiko Kumada;Takahiro Nakamura;Kunihiko Hidaka;Yuichi Tsuboi;Tetsuo Yoshimitsu

Year: 2015 | Volume: 22, Issue: 6 | Journal Article |

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