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Pressboard

About: Pressboard is a research topic. Over the lifetime, 1123 publications have been published within this topic receiving 9089 citations.


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Dissertation
01 Aug 2018
TL;DR: In this article, a purpose-built pulsed electroacoustic (PEA) system has been set up to measure the space charge dynamics in thick oil and pressboard (PB) materials under a temperature gradient through an experimental approach.
Abstract: High Voltage Direct Current (HVDC) power transmission is essential for the development of long-distance power transmission. Within the HVDC conversion system, the most significant apparatus is a HVDC converter transformer. In converter transformers, on the one hand, the high operational electric field is desirable to decrease the dimension, weight, and material usage in converter transformers; on the other hand, the electric field must be lower compared to the dielectric strength to avoid the surface discharge or destructive breakdown of insulation materials. In addition the operation voltage, the electric field is also affected by space charge dynamics in insulation materials. For this reason, extensive efforts have been made to investigate space charge dynamics in the insulation material of converter transformers, such as the oil-impregnated paper. However, the space charge characteristics are not well understood for the thick oil and pressboard (PB) materials under a temperature gradient. Hence, a new purpose-built pulsed electroacoustic (PEA) system has been set up to measure the thick oil and PB space charge behaviour under a temperature gradient. This dissertation comprises the quantitative analysis of the space charge dynamics in thick oil and PB insulation materials under a temperature gradient through an experimental approach. With the purpose-built PEA system, the influential factor of temperature gradient on dynamics of space charge in thick oil and PB has been investigated. The space charge measured from the PEA system depends on the acoustic wave propagation in the insulation materials. The temperature can affect the acoustic velocity and thus space charge distribution. Therefore, for a one-layer sample, the space charge recovery method under a temperature gradient is important to ensure that the correct space charge pattern is acquired. Furthermore, in multilayer samples, an acoustic wave may experience different generation and transmission coefficients that lead to attenuation and dispersion after the propagation through the dispersive materials. Therefore, the space charge recovery method of multilayer samples under the temperature gradient is proposed. With the proposed space charge recovery method under a temperature gradient, the space charge influential factors, such as temperature gradient and multilayer oil and PB, are investigated. Furthermore, the polarity reversal (PR) effect on dynamics of space charge in multilayer oil and PB under a temperature gradient is presented using an experimental approach. The measured space charge is further interpolated into the COMOSOL model to quantitatively evaluate the electric field oil and PB after PR. The difference between the electric field after PR calculated by the Maxwell-Wagner theory and space charge density is compared. The thickness effect on the space charge is investigated on two-layer oil and PB materials. The simulation model is also expanded into four and six layers for the electric field calculation based on the estimated space charge results.

1 citations

Journal ArticleDOI
Jin Fu1, Jian Hao1, Hua Yin1, Gaolin Wu1, Qian Wang1 
TL;DR: In this article, the space charge characteristics of the mixed insulation consisted of oil gap and pressboard with three different moisture content were investigated using the PEA measurement system, and the distortion of the electrical field in the gap and the pressboard was also analyzed.
Abstract: Moisture has a detrimental effect on oil-paper insulation life by lowering electrical breakdown strength. How does the space charge behavior of the oil-paper insulation system consisted by oil gap and oil immersed insulation pressboard with different moisture content? The space charge characteristics of the mixed insulation consisted of oil gap and pressboard with three moisture content were investigated using the PEA measurement system. The space charge accumulation behaviors at the interface between oil gap and pressboard were analyzed. The distortion of the electrical field in the oil gap and pressboard was also analyzed. Results show that there are many charges injected into the oil and the pressboard. The charges accumulated at the interface between oil gap and pressboard. The charges accumulated in the mixed insulation system become less with the moisture content increased. The difference of the electric field strength in the oil gap and pressboard become smaller with the moisture content increased.

1 citations

Proceedings ArticleDOI
02 Jun 2014
TL;DR: In this article, a setup simulating High Voltage DC (HVDC) transformers barriers was developed to demonstrate the effectiveness of an optical fiber (OF) sensor in detecting partial discharges (PD) under these peculiar conditions.
Abstract: A setup simulating High Voltage DC (HVDC) transformers barriers was developed to demonstrate the effectiveness of an optical fiber (OF) sensor in detecting partial discharges (PD) under these peculiar conditions. Different PD detection techniques were compared: electrical methods, and acoustic methods. Standard piezoelectric sensors (R15i-AST) and the above mentioned OF sensors were used for acoustic detection. The OF sensor was able to detect PD acoustically with a sensitivity better than the other detection methods. The multichannel instrumentation system was tested in real HVDC conditions with the aim of analyzing the behavior of the insulation (mineral oil/pressboard).

1 citations

Journal ArticleDOI
TL;DR: In this paper, the effect of oil-paper-pressboard mass ratio and oil replacement on furfural-DP equation was analyzed, and the oil replacement compensation factor was proposed.

1 citations

Patent
17 Apr 2013
TL;DR: In this paper, a hot pressboard adjusting device for the hot press is presented, which is simple and scientific in structure, scientific in design, low in production cost and convenient to popularize.
Abstract: The utility model discloses a hot pressboard adjusting device for a hot press. The hot pressboard adjusting device for the hot press comprises a hot pressboard body and a thermal cycle pipeline which is arranged in the hot pressboard body and used for heating and drying board materials, wherein an adjusting device is arranged between the upper board face and the lower board face of the hot pressboard body. By means of the hot pressboard adjusting device for the hot press, the problem that secondary processing is needed caused by unevenness and warping produced in a hot press process of the board materials is effectively solved. The hot pressboard adjusting device for the hot press is simple and scientific in structure, scientific in design, low in production cost and convenient to popularize.

1 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202321
202266
202140
202059
201966
201882