HiDry72: Short-circuit withstand test upon the biggest ever dry-type power transformer

Abstract

Reliability in power transformers is a key factor, and based on its performance during the life time. Whenever safety for people or property is of primary concern, dry-type transformers are used. Traditionally dry transformers were only for MV distribution applications available, but recently dry-type power transformers were introduced for the 72.5 kV sub-transmission voltage class, with ratings up to 63 MVA. These transformers allow to easily construct substations in any building or underground location, without the need for costly fire protection. This allows to go with higher voltage directly to the main load centers, providing higher power and reducing distribution losses. Meanwhile several reference installations are in operation.