Damage Identification Method for Composite Post Insulator Under Long-term Load
Composite materials are widely used in the electrical equipment with the feature of damage invisibility.After being subjected to long-term environmental loads,the equipment is easy to produce undetectable micro structural damages.In order to identify the damages,one 200 kV composite post insulator was taken as the research object for field dynamic characteristic test under different damage conditions firstly,and the frequency changes under different conditions were obtained.Secondly,numerical simulation was carried out for damage identification of the insulator by using two methods of curvature modal difference analysis and wavelet transform.Finally,the damage curves of the insulator was derived by taking the curvature modal differences as the damage indicators.The study shows that both these two identification methods can effectively identify the insulator damage location,the wavelet transform method is more superior,and the damage curves can be more accurately fitted from the modal curvature differences to determine the size of damage degree.