Abstract
Large scale conversions to Dairy Farming in the Canterbury region, and the associated irrigation requirements, are stretching the capacity of many local electrical substations. In an effort to extend the working life of existing transformers, fans are commonly used to force%ventilate their oil% filled cooling coils. Unfortunately, these fans can give rise to complaints from neighbours because of the noise they produce. This paper discusses a recently installed system to reduce noise levels and improve the mechanical efficiency of the cooling system. Significant noise reductions have been achieved, and further performance can easily be obtained for critical situations. The issue of transformer noise is also considered, with particular reference to the possible use of the cooling fans to mask the 100Hz pure tone which is dominant around transformer installations