Dielectric and Thermal Conductivity of Epoxy Resin Impregnated Nano-h-BN Modified Insulating Paper

Abstract

Epoxy resin-impregnated insulation paper (RIP) composites are used as the inner insulation of dry condenser bushing in the ultra-high voltage direct current (UHVDC) power transmission system. To improve the dielectric properties and heat conductivity of RIP, hexagonal boron nitride (h-BN) nano-flakes are added to the insulation paper at concentrations of 0–50 wt % before impregnation with pure epoxy resin. X-ray diffraction (XRD), scanning electron microscopy (SEM) observations, thermal conductivity as well as the typical dielectric properties of direct current (DC) volume conductivity. DC breakdown strength and space charge characteristics were obtained. The maximum of nano-h-BN modified heat conductivity reach 0.478 W/(m·K), increased by 139% compared with unmodified RIP. The DC breakdown electric field strength of the nano-h-BN modified RIP does not reduce much. The conductivity of nano-h-BN modified is less sensitive to temperature. As well, the space charge is suppressed when the content is 50 wt %. Therefore, the nano-h-BN modified RIP is potentially useful in practical dry DC bushing application.

Thermal and Electrical behaviors of Boron Nitride/Epoxy reinforced polymer matrix composite—A review

“…[37] Mi et al [38] used the plasma technique to increase hydroxylation of BNNSs by bipolar nanosecond pulse dielectric barrier discharge at atmospheric pressure with water to increase thermal conductivity and breakdown strength. Yang et al [39] developed resin-impregnated insulation paper (RIP) by adding h-BN nanoflakes into epoxy, which results in increased thermal conductivity up to 0.478 W/m-K (139%) compared to untreated RIP along with improvement in breakdown strength and F I G U R E 4 Thermal conductivity versus content of nano h-BN [39] [Color figure can be viewed at wileyonlinelibrary.com] F I G U R E 5 Scanning electron microscope (SEM) images of 40 wt% boron nitride (BN) filed epoxy composite with different sizes of BN. [40] (A) 1 μm size of BN/epoxy.…”

“…Mi et al [ 38 ] used the plasma technique to increase hydroxylation of BNNSs by bipolar nanosecond pulse dielectric barrier discharge at atmospheric pressure with water to increase thermal conductivity and breakdown strength. Yang et al [ 39 ] developed resin‐impregnated insulation paper (RIP) by adding h‐BN nanoflakes into epoxy, which results in increased thermal conductivity up to 0.478 W/m‐K (139%) compared to untreated RIP along with improvement in breakdown strength and space charge properties using pulsed electro‐acoustic system.…”

Temperature Effects on the Dielectric Properties and Breakdown Performance of h-BN/Epoxy Composites

“…Yanget al reported that when h-BN was added to an epoxy resin-impregnated insulation paper, its thermal conductivity increased by 139%. Meanwhile, the breakdown strength remained constant and the inhibition of space charges was observed [13]. Zhanget al investigated the effects of the addition of boron nitride nanospheres into the epoxy resin matrix on the thermal conductivity and insulating performance of composites.…”

Analysis and Disposal of Typical Breakdown Failure for Resin Impregnated Paper Bushing in the Valve Side of HVDC Converter Transformer

“…During operation, the ambient temperature of the valve side bushing is high, and its current-carrying central tube carries a large harmonic current component, in addition to the fundamental current. Affected by the harmonic current skin effect, the valve side bushing with insufficient current capacity is prone to insulation failure, which is caused by overheating inside bushing during the highest load period [1][2][3][4][5][6][7][8][9]. In recent years, Yimin, Baoji, Fengjing etc.…”