Space charge behavior in multi-layer oil-paper insulation under different DC voltages and temperatures

Abstract

Oil-paper as a reliable insulation system is widely used in power transformers and cables. The dielectric properties of oil-paper insulation play an important role in the reliable operation of power equipment. However, the formation and dynamics of space charge can affect the performance of insulation material. In this paper, space charge in oil-paper insulation system has been investigated using the pulsed electroacoustic (PEA) technique. A series of measurements were carried out when the insulation system was subjected to different applied voltages at different temperatures. Charge behavior in the insulation system has been analyzed and the influence of temperature on charge dynamics was discussed. The test results show that homocharge injection takes place under all the test conditions, the applied dc voltage mainly effect the amount of space charge, while the temperature has greater influence on the distribution and mobility of space charge inside oil-paper samples.

Effect of the electrode material on the breakdown voltage and space charge distribution of propylene carbonate under impulse voltage

“…[17][18][19] The space charge injected from the electrode weakens the electric field near the electrode and strengthens the electric field of the central region, distorting the initial uniform electric field. We believe that different electrodes have a different space charge injection ability that distorts the electric field between the electrodes to a different degree.…”

Space Charge Behavior of Oil-paper Insulation Thermally Aged under Different Temperatures and Moistures

“…Because oil paper generally presents in the form of multi-layer structure, forming an interface between oil-paper layers, and charge can be easily stored at the interface. Therefore some scholars have paid their attention to space charge dynamics at the interface [9][10][11][12]. Effects of moisture [9], temperature [10] and polarity reversal voltage [11,12] on space charge of multi-layer oil paper have also been studied.…”

“…As oil paper is thermally aged, the inter-unit linkages in cellulose chains are broken and other properties including permittivity and conductivity change [2,10]. These will affect space charge behaviors.…”

Space Charge Behavior in Oil-Impregnated Insulation Paper Reinforced with Nano-TiO2

“…Partial discharge or breakdown may occur in those places where the electrical field strength is strengthened; this can lead to premature failure of the insulation material (Zhang et al 1996;Liu et al 1989). To date, research has focused on the space charge dynamics of oil-impregnated insulation paper affected by voltage level, temperature, and moisture (Morshuis and Jeroense 1997;Ciobanu et al 2002;Tang et al 2010;Zhou et al 2009;Liu et al 1998). Although studies have found that many nanoparticles improve the space charge distribution in insulation materials such as polyethylene and polyimide, there are no reports on how to improve the space charge distribution in oil-impregnated insulation paper (Fleming et al 2005;Huang et al 2009;Wang et al 2009;Zha et al 2010;Thelakkadan et al 2011;Abd El-kader et al 2009;Ahmad et al 1992).…”