Effects of aging on the structural, mechanical, and thermal properties of the silicone rubber current transformer insulation bushing for a 500kV substation.

Zhigao Wang,Xinsheng Lan,Yiqian Zhou,Xinghai Zhang,Fangqiang Wang

doi:10.1186/s40064-016-2549-y

Abstract

In order to analyze the cracking and aging reason of the silicone rubber current transformer (CT) insulation bushing used for 8 years from a 500 kV alternating current substation, characteristics including Fourier transform infrared (FTIR) spectroscopy, mechanical properties analysis, hardness, and thermo gravimetric analysis have been carried out. The FTIR results indicated that the external surface of the silicone rubber CT insulation bushing suffered from more serious aging than the internal part, fracture of side chain Si–C bond was much more than the backbone. Mechanical properties and thermal stability results illustrated that the main aging reasons were the breakage of side chain Si–C bond and the excessive cross-linking reaction of the backbone. This study can provide valuable basis for evaluating degradation mechanism and aging state of the silicone rubber insulation bushing in electric power field.

Highlights

In recent years, the silicone rubber material has been widely used in the external insulation field of high voltage power transmission and transformation due to its excellent electrical insulation property, anti-pollution flashover performance, explosion-proof, hydrophobicity, and hydrophobicity transfer property (Amin and Salman 2006; Reynders et al 1999; Liang et al 2009; Papailiou and Schmuck 2013; Chen et al 2015; Zhou et al 2016)
We have examined the composite insulators of current transformer (CT) (SAS550, MWB Shanghai Transformer Co., Ltd.) with 8 years service time from a 500 kV alternating current (AC) substation in Sichuan Power Grid of China
Characteristics including Fourier transform infrared (FTIR) spectroscopy, mechanical property analysis, hardness, and thermo gravimetric analysis (TGA) have been carried out on the external surface and internal samples of the silicone rubber CT insulation bushing in different parts to study the change of molecular structure and ageing state

Summary

Introduction

The silicone rubber material has been widely used in the external insulation field of high voltage power transmission and transformation due to its excellent electrical insulation property, anti-pollution flashover performance, explosion-proof, hydrophobicity, and hydrophobicity transfer property (Amin and Salman 2006; Reynders et al 1999; Liang et al 2009; Papailiou and Schmuck 2013; Chen et al 2015; Zhou et al 2016). Characteristics including Fourier transform infrared (FTIR) spectroscopy, mechanical property analysis, hardness, and thermo gravimetric analysis (TGA) have been carried out on the external surface and internal samples of the silicone rubber CT insulation bushing in different parts to study the change of molecular structure and ageing state.

Results

Conclusion