Contactless Diagnostics of Dry Transformers During Operation Condition

The examination of the increasing noise in the distribution transformer station next to the offices is the focus of this paper. Office workers' mental health has been found to be disturbed by some features of transformer noise at tone frequencies about 400 Hz, even if the standard for noise exposure in the workplace is satisfactory. The noise analysis is focused on acoustic measurements carried out on two 22/0.4kV power dry transformers with the same performance, while one of them, referred to as “noisier”, negatively affects the working well-being of employees. During the acoustic analysis, a parabolic camera was used to identify the cause of the increased noise from the exposed transformer. This procedure makes it possible to analyze the frequency spectrum with the possibility of 3D observation of the dry transformer and to determine the displayed point with the highest noise and acoustic emission. The analysis was carried out during the operation of only one power transformer under no-load conditions and under real load in order to avoid the mutual influence of emission interference.