Study on the influence of pulse propagation in transformer winding on partial discharge pattern recognition

A partial discharge (PD) signal in a transformer must propagate through the winding to its terminals before it arrives at a monitoring device, so the signal, on which the failure diagnosis is based, must undergo some distortion. In this work, the elemental impulse response of the winding is obtained by detecting the propagation of a pulse signal in the winding. By measuring the nanosecond scale rapid variation of the waveform of model discharges, the rule of the propagation of the discharge pulse signal in the winding under various conditions, including types and locations of the discharge and measuring points, is studied. Based on statistical comparison, the factors which have influence on the diagnosis of the discharge pattern are analyzed, which improves the exactness of the pattern diagnosis in practice