Rafael Murillo

HiDry 72 : The Oil-Free and Safe Power Transformer for Sub-transmission Level

HiDry72 is the safe and environmentally friendly solution in transformer technology for distribution and sub-transmission lines capable of reaching up to 63 MVA and 72.5 kV insulation level. The HiDry72 uses dry-type (non-oil) insulation materials to achieve these ratings. For the customer, this means superior safety and environmental friendliness for people and property. These advantages make the HiDry72 a product very suitable for applications in urban substations, power generation plants, substations located near or in public buildings or sensitive ecosystems, in cavern/underground locations and in crowded public places. This technology also provides the ability to install higher voltage systems directly to the main load centers; providing higher power and reducing distribution losses by reducing the amount of low voltage cable runs. The development of a dry-type power transformer for the 72.5 kV voltage class was already presented in 2011 [1]. Since then, a great interest has been shown in the market for many utilities as well as industries because all benefits inherent to the dry technology. In this abstract we report about the technology and some current projects in operation.

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

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.