Partial Discharge Detection of Transformer Bushing Based on Acoustic Emission and Current Analysis

Abstract

Partial discharge (PD) detection is one of the most important parameters which can classify the insulation condition of the distribution and power transformers. Among several components, the transformer bushing is an essential part that can withstand high voltage levels and guarantee the electrical power system's stability. However, since bushings are subjected to dirt contamination, high dielectric, and thermal stresses, PD activities can arise and lead the transformer to total failure. Therefore, preventive test methods have been proposed in the literature to avoid this issue. In this sense, this manuscript proposes a new approach to assess PD evolution in transformer bushing by acoustic emission and current analysis. An increased PD activity was induced in an insulation bushing, which was sensed by a low-cost piezoelectric transducer, and a hall effect current sensor. Experimental results showed that the proposed Fast Fourier Transform frequency average, and Energy analysis were able to identify the PD evolution in the bushing transformers.