To main content

LiPe - Transformer Liquid Dielectric Withstand Performance

This project is working on new insulation liquids for transformers that can be safer, more sustainable, and better at cooling.

Contact persons

figure about LiPe-project

Background: Investments in the power system

Considerable investments and reinvestments are needed in the power grid in the coming years, all of which must be environmentally sound and highly reliable. 

Liquid-insulated transformers are keystones of the electrical power system. Ensuring safe transformer operation is essential for electrification, access, and security of supply of energy. 

Assessment of the properties of new liquids

There is currently a large influx of new insulating liquids entering the transformer market, offering advantageous properties relating to biodegradability, reduced fire risk, and improved cooling properties compared to the conventional mineral oils. 

However, there are challenges in assessing the most crucial property of a dielectric liquid – its function as an electrical insulant, to resist an electrical breakdown and destruction of the transformer. 

The lack of proper test methods and standards for documenting their electric withstand voltage leaves industry with problems in adjusting their designs and end users with uncertainty in using new liquids.

Developing new and better test standards 

LiPe will advance the understanding and application of insulating liquids for transformers, covering the entire value chain from production to end-use.

The measurements, modelling, and experimental results will facilitate basic understanding and new and better test standards. This work will mitigate risks and uncertainties to promote the safe use of insulating liquids in new and old power transformers.

The project lays a foundation for predicting and testing dielectric performance of insulating liquids for transformers by:

  • Establish methods for documenting, predicting, and testing the performance of liquids, qualifying them use in specific transformer designs.
  • Test the hypothesis that breakdown in dielectric liquids is governed by electron avalanches in an electric field that may be space-charge-limited (SCLF) to facilitate development of the models. 

The project will also: 

  • Measure and develop models of high-field conductivity and SCLF in insulating liquids.
  • Develop atomistic modelling methods relevant for high-field conduction.
  • Test the hypothesis of electron avalanches in the liquid for positive streamers.
  • Establish correlations between liquid properties and small-scale dielectric performance.
  • Perform large-scale breakdown experiments to support and verify modelling and small-scale findings.
  • Contribute to future test standards for dielectric liquids

PhD

The project has two PhD positions; one affiliated with NTNU’s Department of Chemistry and the other with NTNU’s Department of Electric Energy.

Key facts

Project duration

2024 - 2028

Funding

LiPe is a Knowledge-building Project for Industry funded by the Research Council of Norway and the partners. 

Explore research areas