A new method for analysing transformer condition using frequency response analysis

In modern electrical transmission and distribution systems, power transformers are critical components within the network. In the event that a failure occurs in service, the impact can be far reaching. Not only causing extended outages, but costly repairs and potentially serious injury or fatality can result. The ageing transformer population increases the likelihood of failure so a reliable diagnostic tool is required to determine the remaining life of these assets. Frequency Response Analysis (FRA) has been growing in popularity in recent times as a tool to detect mechanical deformation within power transformers. However, because FRA relays on graphical analysis, it calls for an expert person to analyse the results. So far, there are no standard codes for FRA interpretation. This paper introduces an alternative method for analysing FRA results using the polar plot. Various types of faults have been simulated to assess its impact on the polar plot. The technique is easy to be implemented and automated so that the requirement for expert personnel can be eliminated.