Transformers are essential in the electricity grid. Our research has created an HTS transformer and is enhancing the capability of conventional transformers.

Conventional transformers

Electricity is delivered from a generator to a consumer via transformers that step up and step down the voltage through the transmission and distribution network.

Conventional transformers are made of windings of copper or aluminium wire immersed in oil. This technology has been optimised during more than a century of development, and efficiencies for large power transformers now reach 99.7% percent and higher.

We are working with a number of industry partners, including Auckland based transformer manufacturer ETEL, working with us to improve the lifetime and efficiency of conventional transformers. Our research involves developing new sensors to install within the transformer to ascertain its condition.

HTS transformers

Transformers using HTS (high temperature superconducting) wire immersed in liquid nitrogen are a new alternative to the conventional devices. These transformers can be smaller, lighter and more efficient. They also eliminate the fire and environment hazards that accompany oil-immersed transformers.

HTS transformer—proof of concept

In 2013, the Robinson Research Institute and its Australasian partners designed, built and tested a three phase 1 MVA 11 kV/400 V HTS (high temperature superconducting) transformer. The low voltage winding made from YBCO Roebel cable achieved a current rating of 1400 A, which is the highest ever demonstrated in an HTS transformer.

The transformer matches the 99 percent efficiency of conventional 1 MVA transformers (including the energy cost of refrigeration).

Our transformer loss modelling predicts that an HTS 40 MVA substation transformer with a high efficiency cryocooler would exceed the 99.7% efficiency demanded at this MVA rating.

The HTS transformer design and build was a cooperative project involving the following industry & research partners:

  • Wilson Transformers, ETEL (transformer manufacture)
  • Fabrum Solutions (cryostat and composite manufacture)
  • General Cable Superconductors (Roebel cable manufacture)
  • HTS-110 (HTS system manufacture)
  • Northpower, Vector (utilities companies).
  • Callaghan Innovation (cryo-engineering, assembly and testing)

Further development

Our ongoing research partnerships are helping New Zealand industries commercialise HTS transformer technology.

We are leading the research effort in these areas:

  • improving fault current performance
  • reducing the cost of the cryogenic system
  • further reducing the electrical loss in the windings.


View our publications about transformers, including details of the transformer modelling work.