Analysis of aged insulating oil for early detection of incipient fault inside the high voltage equipment

Abstract

Ageing of the transformer depends on several factors especially electrical and thermal stresses. Due to which incipient faults occurs which in turn if left undetected will cause deterioration and eventually lead to failure of the transformer. The presence of faults in transformer results in chemical decomposition of the insulating transformer oil. The transformer oil is deteriorated due to the combination of the ageing process such as partial discharge (PD), thermal ageing and electrical arcing. The effects of different ageing processes and contamination of insulating oil of a transformer has been studied and verified using most popular optical method such as Ultra Violet (UV) Spectrophotometer and Fourier Transform Infrared (FTIR). The spectrums of UV spectrophotometer and FTIR have potential to analyse the oil quantitatively and qualitatively. In this work, two type of analysis is being carried out firstly the analysis of transformer oil which are aged with course of time during the transformer operation and secondly the analysis of laboratory aged transformer oil. Further, the analysis of the result of UV spectrophotometer and FTIR is carried out and finally ageing assessment using oil contamination level identification is given. The presented detection method has high potential to determine the types of faults occurred and their effect on the transformer oil by which the condition assessment can be performed easily.