Microscopic view of aging mechanism of polyimide film under pulse voltage in presence of partial discharge

Wu, Guangning; Wu, Jiandong; Zhou, Liren; Gao, Bo; Zhou, Kai; Guo, Xiuping; Cao, Kesheng

doi:10.1109/tdei.2010.5412010

Cited by 42 publications

(16 citation statements)

References 19 publications

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“…In these works, molecular chain scissions were found to occur on the polymer surface and to generate polymer radicals. These evolutions in samples may indicate that the deterioration of insulation is severe and may extend from surface, considering the translucent nature of the material [38]. They may be often accompanied by extensive deterioration in the mechanical properties of the materials, such as tensile strength, impact strength and elongation, all of which are important parameters in the performance of an insulating material.…”

Section: Termination Stepmentioning

confidence: 99%

Effect of Ultraviolet Radiations on Medium and High Voltage Cables Insulation Properties

Hedir¹,

Moudoud²

2016

IJET

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Under operating conditions effect, insulated power cables can undergo critical degradations. Ultraviolet (UV) radiations are one of the most destructive constraints which affect the properties of the material used for insulation. Because of its good properties, crosslinked polyethylene (XLPE) is widely used in medium voltage (MV) and high voltage (HV) cables insulation. Regardless of its excellent performances, XLPE can degrade when exposed to UV. The objective of this work is to report experimental results concerning the effect of accelerated UV ageing on the properties of XLPE insulation. For this purpose, dielectric characterization, visual observations and scanning electron microscopy (SEM) analysis are performed to assess the extent of ageing. Obtained results show that UV ageing affects greatly the XLPE insulation. So, an evolution in the dielectric properties (dielectric constant, dissipation factor, dielectric loss index and AC volume resistivity), color change and deterioration of surface morphology with ageing time are noticed.

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Section: Termination Stepmentioning

confidence: 99%

Effect of Ultraviolet Radiations on Medium and High Voltage Cables Insulation Properties

Hedir¹,

Moudoud²

2016

IJET

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“…Recently, Zha et al found that nano-TiO 2 particles could improve the dielectric strength, lifetime, and space charge characteristics based on the dielectric properties tests of PI/TiO 2 nanocomposites 19 20 . Zhou et al attributed the enhanced corona resistance of PI nanocomposites to the high charge transport capacity of nanostructure based on the corona-aging and breakdown tests under high frequency square wave pulses 21 24 . However, most of the researches focus on the comparison between pure PI and nanocomposites at the same temperature.…”

mentioning

confidence: 99%

“Thermal Stabilization Effect” of Al2O3 nano-dopants improves the high-temperature dielectric performance of polyimide

Yang

et al. 2015

Sci Rep

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Insulation performance of the dielectrics under extreme conditions always attracts widespread attention in electrical and electronic field. How to improve the high-temperature dielectric properties of insulation materials is one of the key issues in insulation system design of electrical devices. This paper studies the temperature-dependent corona resistance of polyimide (PI)/Al2O3 nanocomposite films under high-frequency square-wave pulse conditions. Extended corona resistant lifetime under high-temperature conditions is experimentally observed in the 2 wt% nanocomposite samples. The “thermal stabilization effect” is proposed to explain this phenomenon which attributes to a new kind of trap band caused by nanoparticles. This effect brings about superior space charge characteristics and corona resistance under high temperature with certain nano-doping concentration. The proposed theory is experimentally demonstrated by space charge analysis and thermally stimulated current (TSC) tests. This discovered effect is of profound significance on improving high-temperature dielectric properties of nanocomposites towards various applications.

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“…The dissipation time under higher frequency is longer. 4. For the fluorinated sample, the surface charge density is lower and decays much faster than that of the unfluorinated one under the same conditions.…”

Section: Discussionmentioning

confidence: 85%

“…Serdyuk et al investigated charging of polymer surfaces by means of impulse corona discharges and concluded that charge deposition was different in case of glow corona and burst corona [3]. Wu et al studied the structure change of polyimide film aging under pulse voltage and found that the degradation of structure in polyimide propagates from surface to interior with continuous aging [4]. The surface charge distribution of PTFE insulators under impulse voltage was measured and analyzed by Wang et al and it was found that micro-discharge was the prerequisite of the surface charge accumulation [5].…”

Section: Introductionmentioning

confidence: 99%

Effect of direct fluorination on surface charge of polyimide films using repetitive pulsed power

Liu

Guo

2015

IEEE Trans. Dielect. Electr. Insul.

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As one of the basic insulating materials, polyimide films have been widely used in turn to turn insulation and turn to ground insulation in wind turbine generators. However, the pulse voltage from the converter often causes overvoltage and localized high electrical field in the insulation system. Surface charge could affect the dielectric property and cause the breakdown of insulation. Direct fluorination is a method to modify the surface layer of the polymers without changing the bulk properties. As a result of the fluorination, hydrogen atoms are replaced by the fluorine atoms and the component of the polymer surface is changed, which can influence the surface charge accumulation and affect the electrical properties. The experiment in this paper was focused on the effect of direct fluorination on surface charge of polyimide films under pulse voltage. The polyimide films with the fluorination time of 15, 30, 45 and 60 min were prepared, together with the unfluorinated one as a comparison. Surface charging was performed by corona discharging using repetitive pulse power at the temperature of 25 °C with the relative humidity of ~45%. The rising time of the pulse was 25 μs and the frequency was set at 200, 400, 600 and 1000 Hz, respectively. The surface charge decay was measured using a specific probe coupled with an electrostatic voltmeter. The results showed that the surface charge behavior was affected by the fluorination, corona discharging time, pulse voltage amplitude and frequency. Index Terms -Polyimide film, direct fluorination, repetitive pulse, corona discharge, surface charge, trap. Boxue Du (M'00-SM'04) received the M.E. degree in electrical engineering from Ibaraki University and the Ph.D. degree from Tokyo University of A&T.

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Microscopic view of aging mechanism of polyimide film under pulse voltage in presence of partial discharge

Cited by 42 publications

References 19 publications

Effect of Ultraviolet Radiations on Medium and High Voltage Cables Insulation Properties

Effect of Ultraviolet Radiations on Medium and High Voltage Cables Insulation Properties

“Thermal Stabilization Effect” of Al2O3 nano-dopants improves the high-temperature dielectric performance of polyimide

Effect of direct fluorination on surface charge of polyimide films using repetitive pulsed power

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