基于光声麦克风的GIS典型绝缘缺陷声发射特征研究OA

Various insulation defects in gas insulated switchgear(GIS)are the primary cause of insulation perfor-mance deterioration and safety accidents.The conventional ultrasonic testing method,due to the limit of the re-sponse frequency band of the piezoelectric sensors and the resonance feature of the GIS enclosure,has no way to ob-tain accurately the broadband partial discharge signals,thereby affecting the detection effectiveness.In this paper,a built-in broadband photoacoustic microphone technology is employed to acquire the broadband acoustic emission sig-natures of such four typical defects as metal protrusions,free particles,floating potential,and internal air gaps in ep-oxy insulation.The results show that acoustic signals generated by metal tip defect and free particle defect are cluster-shaped,with a longer duration and a lower peak frequency,while that of floating potential defect and internal air gap in epoxy insulation is pulse-shaped,with a short duration and a higher peak frequency.The peak frequency and am-plitude of insulation defect acoustic signals are strongly correlated with defect size.The use of equivalent time and equivalent frequency method can distinguish the four types of defect sound signals effectively.The research results can provide reference for the detection and diagnosis of GIS/GIL insulation defects.