Effects of test cable ground extensions on repeatability of frequency response analysis measurements on power transformers

Power transformers are critical and expensive components of power networks, especially large power transformers. Assessment of their condition and diagnosis of faults involves several tests. One of the most important aspects of transformer assessment is the detection of mechanical displacements or deformations of transformer windings that might have occurred, e.g., during short-circuit events in the power network, or during transportation of the transformer to the site from the factory or workshop.