Vibration Analysis of Transformer as an Early Diagnosis of Internal Transformer Faults: (Case Study of Transformer #3 GIS Kemang)

Abstract

Transformers are vital in the distribution of power. Their reliability is of utmost importance. Over time, these machines can wear down, leading to potential failures and safety issues. This study aims to identify partial discharge in Transformer #3 GIS Kemang, which has been running for almost three decades. Acoustic Emission method is considered to examine its internal state and gauge the risks of failure. This method was prompted by a troubling rise in acetylene levels from the Dissolved Gas Analysis, revealing signs of arching. High-Frequency Current Transformer and Acoustic Emission sensors were placed in high-risk locations to track PD activity during regular operations. Data were collected in real time with a PowerPD TP500A system, allowing for the classification of PD events based on pulse intervals. The findings revealed a source of partial discharge on the HV/Tubular side. The AE Sensors captured a repeating butterfly-shaped pattern of wave with intervals of 20.332 milliseconds, and the HFCT sensors picked up bursts with intervals of 0.102 milliseconds. Following the Acoustic Emission and High-Frequency Current Transformer testing, a visual inspection of the transformer's internal components was conducted and confirmed the presence of discharge marks (treeing) on the pertinax magnetic shunt, corroborating the AE sensor data that indicated signs of electrical stress that could hasten the decay of insulation. Additionally, spot marks were observed on the insulation material surrounding the high-voltage (HV) Phase T winding, further supporting the hypothesis that electrical stress contributed to insulation breakdown.