Power Transformer Noise Its Characteristics and Reduction

Audibility characteristics of the ear and the units used for measuring noise are briefly discussed. A theoretical investigation was made to determine the different force components and other causes of transformer hum. Surface vibration measurements were made on transformer parts to determine the sources which cause noise in transformers and how these noise sources are afected by variations in operating conditions. Noise surveys were made to measure the range of intensities, the frequency characteristics and distribution of sound from transformers in service. The effects of substation acoustic conditions on noise distribution were investigated.