AUTHOR=Zhang Xinlong , Cheng Li , Liu Yunfan , Tao Bo , Wang Jiuyi , Liao Ruijin 

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

JOURNAL=Frontiers in Materials

VOLUME=Volume 9 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/materials/articles/10.3389/fmats.2022.995516

DOI=10.3389/fmats.2022.995516

ISSN=2296-8016

ABSTRACT=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, due to production and design defects and aging problems during operation, tiny structural defects often occur in insulating materials, especially under the action of high electric field strengths. These small defects are prone to partial discharges and breakdowns, thus affecting the safety of high voltage power equipment. Therefore, it is necessary to carry out non-destructive testing for such tiny defects. Such defects are small in size, easily buried in the material, and even some are wrapped in metal, which in turn requires very high detection accuracy, but traditional methods are difficult to achieve, so NDT technologies for tiny defects within insulating materials have become a research hotspot in the field of electric power in recent years. This paper firstly introduces the sources of tiny defects in solid organic insulating materials for electrical equipment. Secondly, the harm caused by structural defects is elaborated. Finally, emerging NDT methods and their advantages and limitations in defect detection are described in detail. The review aims to provide the reader with a comprehensive overview of most of the NDT techniques used in the detection of tiny defects within solid organic insulating materials for electrical equipment and their most salient features.