Insulation Problems in Medium Voltage Stator Coils Under Fast Repetitive Voltage Pulses

Haq,; Jayaram,; Cherney,

doi:10.1109/papcon.2007.4286278

Cited by 6 publications

(6 citation statements)

References 21 publications

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“…The previous investigation of the rise in the surface temperature in the stator coils 30 indicated that an average increase of 10°C is observed with a uniform increase in the switching of 1 kHz under a square-wave voltage of 5 kV peak. This means that the thermal effects of high frequency become more obvious with the increasing frequency, and its temperature can rise to 220°C at 20 kHz.…”

Section: The Influence Of Hf Thermal Effectsmentioning

confidence: 96%

Surface Degradation of Oil-Immersed Nomex Paper Caused by Partial Discharge of High-Frequency Voltage

Zhang²,

Wang³

et al. 2022

J. Electron. Mater.

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The oil-paper insulation of high-frequency (HF) transformers frequently withstands high-frequency over-voltages at frequencies of several kHz and above. This leads to the occurrence of partial discharge (PD), which causes premature insulation failure in HF transformers. In order to investigate the effect of PD under high-frequency stresses on oil-impregnated Nomex paper, this paper analyzes the surface morphology, bond-broken types of the molecular chain, and product types formed for oil paper after PD degradation. Then, the damage mechanism of oil-immersed Nomex paper between high-frequency and AC stress is explored. The experimental results show that the branches of creepage do not exist in the oil-paper insulation during the entire discharge process under high-frequency stresses, and that their damage degree is higher than that of AC stress. This is mainly because the benzene ring of oil-impregnated Nomex paper is destroyed and opened caused by high-energy particles, the heating effect in HF discharge, and the bulk effect. These results help to improve the design theory of insulation structures and to develop PD-resistant insulation materials in HF transformers.

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Section: The Influence Of Hf Thermal Effectsmentioning

confidence: 96%

Surface Degradation of Oil-Immersed Nomex Paper Caused by Partial Discharge of High-Frequency Voltage

Zhang²,

Wang³

et al. 2022

J. Electron. Mater.

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“…To identify the location of the sound source using the arrival time difference among microphones, these require a least three microphones in three dimensional space [8] [9]. Also the computation burden is so heavy that the researches on the reduction of computations are necessary.…”

Section: Bad Insulator Detection Algorithm Using Microphone Arraymentioning

confidence: 99%

“…This is a real situation with low reliability and high risky inspection. To prevent the accidents and to improve the inspection reliability, it is time to replace the human operators by the inspection robots [8].…”

Section: Introductionmentioning

confidence: 99%

Bad insulator detection algorithm using microphone array

Ha¹,

Lee

2010

2010 IEEE/ASME International Conference on Advanced Intelligent Mechatronics

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The paper proposes a new error detection algorithm of bad insulator, a part of high voltage equipment. Hierarchical fault detection method for the high voltage equipment using a microphone array to detect the location of faulty insulator and the thermal image camera to verify the fault and stores the image, respectively. There are partial arc discharges on the faulty insulators, which generate specific patterns of sound and spectrum. Detecting the signal using the microphone array, the location of the faulty insulator can be estimated. The 6th band-pass filter and auto-correlation scheme was applied to remove noise signal from wind or external influence. When the mobile robot carries the thermal cameras to the possible place of the fault insulator, the faulty insulators or power transmission wires can be detected by the thermal images, which are caused by the aging or natural erosion. Finally, the CCD camera captures the image of the faulty insulator for the record. The detection scheme of a fault location using the microphone array and the thermal images has been proved to be effective through the real experiments. As a result of this research, it becomes possible to use a mobile robot with the integrated sensors to detect the fault insulators instead of a human being.978-1-4244-8030-2/10/$26.00 ©2010 IEEE

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“…The electrical exposure on the insulation system caused by such distorted supply voltage may lead to the degradation and the breakdown of powertrain devices (i.e. motors, cables) [10,[20][21][22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Accumulative effect of partial discharges at impulse voltage wave tail

Florkowski

2020

IET Science, Measurement & Technology

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Insulation Problems in Medium Voltage Stator Coils Under Fast Repetitive Voltage Pulses

Cited by 6 publications

References 21 publications

Surface Degradation of Oil-Immersed Nomex Paper Caused by Partial Discharge of High-Frequency Voltage

Surface Degradation of Oil-Immersed Nomex Paper Caused by Partial Discharge of High-Frequency Voltage

Bad insulator detection algorithm using microphone array

Accumulative effect of partial discharges at impulse voltage wave tail

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