Improved Thermal Management in Dry Transformer

Abstract

Dry type transformer is a popular choice for application wherein flame-retarding, self-extinguishing and low- maintenance is desired; e.g. wind turbines, underground- substations etc. As their makeup involves no-oil, the cooling of coils is essentially by natural convection of air. With increase in demand for higher-ratings and stringent limitation on coil temperature rise, convectional design of thermal management has severe limitation on meeting these requirements. Also, conventional approach of thermal management leads to increased equipment cost and foot-print. This paper discusses a novel methodology of improving the heat dissipation in dry transformers with low- cost retrofit-able systems that increase the heat dissipation rate significantly.