The Application of a New Process Method for End Effects of EMD in the Insulator State Diagnosis

The current signal of the dirty high-voltage is non-stationary signals, which contains rich characteristics and the extent of the information of the insulator flashover, in order to accurately extract these features we can use Hilbert-Huang transformation (HHT) method which has developed in recent years. EMD is the core of it, but as a new signal processing methods, in addition to the need for further proof of the theory of things, it still has many areas for improvement. The end effect is one of the issues which is needed to be resolved immediately. Therefore, based on the existing methods and synthesis the advantage of the closed-loop mirror extension method and the general increasing in extreme point, then we improve these methods for our using. Then we use the combination of symmetrical extension of extreme points and the new improved no-overshoot cubic spline fitting algorithm to improve the EMD algorithm. Finally, we use an example to verify the effectiveness of the method.