A review of non-destructive methods for the detection tiny defects within organic insulating materials

In recent years, solid organic materials such as silicone rubber and epoxy resin have been widely used in electrical equipment due to their excellent insulation properties. However, a result of manufacturing design flaws well aging issues during operation, the insulating linked state no longer fit tightly tiny structural defects (defect size less than 10 mm) develop, debonding at composite interface, pores or cracks within material, etc. Tiny are prone partial discharges breakdowns, compromising safety high-voltage power equipment, particularly when subjected strong electric fields. Therefore, it is necessary carry out non-destructive testing (NDT) for defects. Such small size, easily buried even some wrapped metal, which turn requires very high detection accuracy, but traditional methods difficult achieve, so NDT technologies become research hotspot field years. This paper firstly introduces sources equipment. Secondly, harm caused by elaborated. Finally, emerging advantages limitations defect described detail. The review aims provide reader with comprehensive overview most techniques salient features.