Degradation of cross linked polystyrene by repetitive impulse surface flashovers in vacuum

Surface flashover is a devastating electronic avalanche along the gas–solid interface when a high electric field is applied, which is a potential issue that threatens the safe operations of advanced power electronic, electrical, and spacecraft applications. However, the underlying physical mechanisms for surface flashover development are still under investigation owing to the complex charge transport processes through the gas phase, solid phase, and gas–solid interface. In this study, the history of surface flashover theory in the last 50 years is introduced, and several key questions are reviewed from the perspective of the competing mechanisms of charge transport: the role of each phase in a surface flashover, the origin of surface charging, and effects of traps in solid on surface flashover. Then, some suggestions involve charge transport processes in each phase, and their correlations are put forward, and a predictable ‘charge transport competitive flashover model’ is proposed by clarifying the competing mechanisms of charge transport processes through multiple phases. This study summarises the history and hot topics of physical mechanisms of surface flashover proposed based on classic and recent progress and offers promising routes for developing a more precise surface flashover theory and improving surface flashover performances.

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“…); (2). Voltage form (voltage category [62,63], voltage waveform [16,64,65], conditioning [65][66][67] etc. ); (3).…”

Section: Insufficiencies Of Existing Surface Flashover Modelsmentioning

confidence: 99%

Surface flashover in 50 years: Theoretical models and competing mechanisms

Liu

Ohki

et al. 2023

High Voltage

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“…Void interfaces are very common in power insulation equipment, which can lead to a severe degradation of insulation performance [29]. When internal defects have developed to a certain degree, partial breakdown may occur, which can result in carbonization channels [30,31]. In addition, metal interfaces can also occur in insulation equipment, such as the metal sheaths of high-voltage cables [32], as well as metal impurities that intrude into the material during manufacture and operation [33,34].…”

Section: Experimental Samplesmentioning

confidence: 99%

A Terahertz Identification Method for Internal Interface Structures of Polymers Based on the Long Short-Term Memory Classification Network

Wang

Mei

et al. 2022

Polymers

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Polymers are used widely in the power system as insulating materials and are essential to the power grid’s security and stability. However, various insulation defects may occur in the polymer., which can lead to severe insulation accidents. Terahertz (THz) detection is a novel non-destructive testing (NDT) method that is able to detect the interface structures inside polymers. The large quantity of information in the THz waveform has potential for the identification of interface types, and the long short-term memory (LSTM) network is one of the most popular artificial intelligence methods for time series data like THz waveform. In this paper, the LSTM classification network was used to identify the internal interfaces of the polymer with the reflected THz pulses of the internal interfaces. The experiment verified that it is feasible to identify and image the void interfaces and impurity interfaces in the polymer using the proposed method.

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“…Due to its exceptional dielectric properties, polystyrene (PS) is widely used in electrical applications, particularly in high-voltage direct current (HVDC) capacitors. Its dielectric properties, as well as its optical and electromagnetic performances, make it a promising candidate for insulation applications [4]. Naturally, PS, like all polymers, undergoes service-related stresses that impact its dielectric performance [5].…”

Section: Introductionmentioning

confidence: 99%

Investigation of electrical ageing effects on the structural and electrical properties of polystyrene by charging and discharging current method

Hedir,

Slimani,

Moudoud

et al. 2024

Phys. Scr.

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This study focuses on isothermal charging and discharging currents in polystyrene (PS). It is a well known fact that the discharging current is almost the mirror symmetry of the charging current at low electric fields. However, the experimental results presented and discussed in this study have revealed the possibility of an abnormal discharging current (ADC) flowing in the same direction as the charging current. Furthermore, electrical measurements implied that the electrical ageing of PS resulted in a significant increase in the charging current, even for extended ageing periods. Moreover, the intensity and duration of the reverse discharging current have evolved with electrical ageing. This characteristic can be attributed to the presence of ionic impurities both trapped at the polymer surface and in the bulk structure. To highlight the structural changes induced by electrical ageing, detailed structural analyses were conducted using Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analysis. 

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Degradation of cross linked polystyrene by repetitive impulse surface flashovers in vacuum

Cited by 24 publications

References 27 publications

Surface flashover in 50 years: Theoretical models and competing mechanisms

Surface flashover in 50 years: Theoretical models and competing mechanisms

A Terahertz Identification Method for Internal Interface Structures of Polymers Based on the Long Short-Term Memory Classification Network

Investigation of electrical ageing effects on the structural and electrical properties of polystyrene by charging and discharging current method

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