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

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

doi:10.1109/tdei.2019.008118

Cited by 8 publications

(1 citation statement)

References 12 publications

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“…Stress grading tape (SGT) or paint (SGP) with the electric field-dependent conductivity is also wound so as to cover the end of the CAT, in order to control the potential distribution along the coil. Although the SG system works well under power frequency waveforms, and has been used for high voltage rotating machines over decades, the recent researches pointed out that the high frequency repetitive voltage pulses cause the electric field enhancement and the excessive Joule heating [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

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

Umemoto

Nakamura

2021

IEEE Trans. Dielect. Electr. Insul.

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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 time-consuming numerical computations are proposed. As a result, the maximum power density and the temperature rise increase nearly linearly with increasing fundamental and the carrier frequencies. It is suggested that power dissipations in the SG layer by the fundamental frequency component of a PWM waveform and those by the carrier frequency component can be clearly separated. Moreover, the estimated power densities and temperature rises based on the analytical approximations show reasonable agreement with the numerically computed ones, which indicates the validity of the proposed estimation method.

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Section: Introductionmentioning

confidence: 99%

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

Umemoto

Nakamura

2021

IEEE Trans. Dielect. Electr. Insul.

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Polymer Composites for Generators and Motors

Muto

Umemoto

Mabuchi

2021

Polymer Composites for Electrical Engineering

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Experiment of electrothermal stress for different types of end turn grading in the inverter‐fed form‐wound windings

Zhao,

Wang,

Zhu

et al. 2024

High Voltage

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End turn grading with resistive–capacitive coupling experiences severe electrothermal stress when subjected to pulse width modulation (PWM) voltage. In this paper, several experiments and simulations were carried conducted for four types of end turn grading. First of all, the temperature rise in the end turn grading increased with a decrease in rise time. When the rise time was less than 500 ns, the temperature rise at the terminal was higher owing to the increased capacitive current coupled from the main wall insulation. Further, the current in the linear region exhibited minimal variation at different fundamental frequencies resulting in synchronized the temperature rise at the terminal and overlap. Furthermore, the jump voltage was the key factor influencing temperature rise in end turn grading, confirmed by comparing different voltage magnitudes. Finally, the transient behaviour of the maximum field in the stress grading material was determined at rise time. The experimental and simulation results indicate that balancing and interdependently addressing the electrical and thermal stress protection in end turn grading is crucial. The study aims to provide an experimental and theoretical foundation for an insulation system of inverter‐fed rotating machinery operating under PWM voltage.

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

Cited by 8 publications

References 12 publications

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

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

Polymer Composites for Generators and Motors

Experiment of electrothermal stress for different types of end turn grading in the inverter‐fed form‐wound windings

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