A new technology of GIS partial discharge location method based on DFB fiber laser

Abstract

With the increase of voltage levels and the expansion of power grids, GIS equipment has been widely used in the power industry. Due to the small size of GIS and the tight distribution of internal devices, many traditional preventive test items cannot be carried out. The stable operation of GIS equipment is essential to the safety of the power grid. According to past experience, the deterioration of insulation performance is the biggest threat to the safe and stable operation of GIS. GIS partial discharge online monitoring methods can be roughly divided into two categories: electrical monitoring methods and non-electric monitoring methods. The accuracy of traditional electrical detection methods such as pulse current method is general. Although the ultra-high frequency method has strong anti-interference and partial discharge source positioning ability, as the distance from the partial discharge source increases, the signal attenuates greatly; Non-electric monitoring methods such as optical monitoring and chemical detection are only suitable for offline detection, and are not applicable to the running GIS; while the acoustic method is non-invasive, which can locate the partial discharge source and is not affected by the external noise of the GIS; When a partial discharge occurs inside the GIS, the generated acoustic signal will cause the GIS cavity wall to vibrate. The acoustic DFB fiber vibration sensor can be used to detect the cavity wall vibration to achieve the purpose of detecting the partial discharge inside the GIS. It is also possible to directly use the ultrasonic sensor to detect the ultrasonic signal generated by its discharge to determine whether a partial discharge has occurred in the GIS. In this paper, two methods, DFB fiber laser sensing technology and ultrasonic sensors, are used to detect partial discharges, and their reliability and sensitivity are analyzed.