Study on the nondestructive detection method of composite insulator internal defect based on microwave reflection

In order to realize the internal defect detection of composite insulator, the detection method based on microwave reflection is proposed in the study. Firstly, the significant fluctuation of microwave reflection signal as internal defect appears provides the possibility of using microwave reflection to detect the defect. Then, plate sample without defects is detected and the reflection signal intensity fluctuates within 0.2V which can be attributed to the systematic error. The artificial manufacturing defects contained in the plate sample can be effectively detected, and the minimum defect size is about 4mm wide and 0.3mm deep. Carbon deposition near the defect due to ablation may cause a decrease of the detected reflected signal intensity. Finally, it is proved that internal defects in the actual insulators can be successfully detected using the device and method proposed in this study.