Research On Ultra High Frequency Detection And Diagnosis Of Partial Discharge In Power Transformer

The power transformer is one of the most important electrical equipment in the electric power system,its performance is directly related to the safe and economical operation of power system stability,but at the same time it is relatively weak insulation strength equipment in electric power system.Point of transformer partial discharge transformer manufacturing stage may be defective,may also be the insulation deterioration of the long running process of various transient overvoltage caused,so the early performance of transformer insulation fault is usually between the partial discharge of oil paper insulation.Partial discharge monitoring and diagnosis has important significance to the realization of power line monitoring and intelligent power grid operation of transformer.The principle of partial discharge are analyzed and focus on the mechanism of ultra high frequency electromagnetic signal,the propagation characteristics of transformer are analyzed.Through the actual measurement of the transformer four typical partial discharge models corresponding to the waveform are ball gap discharge,suspended discharge,surface discharge and needle plate discharge.The signal feature extraction method of ultra high frequency partial discharge of transformer based on generalized S transform,this method has obvious advantages for feature extraction of non-stationary signal.