Discriminant approach to the GIS mechanical fault diagnosis based on the K-L divergence of vibration signals

摘要

Mechanical malfunction or failure is the principal failure type of gas insulated switchgear(GIS) within transformer substations. Therefore, on-line monitoring of the mechanical characteristics of GIS is of utmost significance to achieve safe, stable and reliable operation of power systems. a simulated GIS is constructed in laboratory and two common GIS faults like screws loosening and free particle vibration are built on it. Through evaluating the values of K-L divergence between normal vibration signal and screws loosening signal, free particle signal respectively, it is concluded that contrasted to the K-L divergence between two normal vibration signals without fault condition, the K-L divergence decreases significantly when GIS is in screws loosening fault condition; while it increases significantly when GIS is in free particle fault condition. Therefore, the K-L divergence could be an index to distinguish between free particle fault and screws loosening fault. This method would be of significance to find out potential faults and fault positioning of GIS in early stage.