The power transformer is the most expensive single asset in a grid substation, carrying a price tag of up to 80 million NOK, due to increasing demands of materials (copper) and labour costs.
Its lifespan hangs largely on the paper insulating its windings.
Over time the paper ages, loses strength and leaves the transformer vulnerable to short circuits.
Demand for electricity is climbing as society electrifies, while the transformer fleet grows steadily older.
Reliable transformers are therefore critical to the green energy transition. However, there is still no recognised standard for measuring how well different papers resist ageing.
SPECTRA, a joint industry project, will lay the groundwork for new international test standards.
The project is developing a more reliable method for measuring the degree of polymerisation (DP) in cellulose, which reveals how far ageing has progressed.
It also includes accelerated ageing tests that allow insulation systems to be compared head-to-head, and will screen commercial paper grades in a range of insulating liquids, including esters.
The international collaboration between Spectra and a CIGRÉ (a global non-profit network for power system expertise) working group is contributing to the development of proposed modifications to DP measurement practices. The outcomes of this work are expected to provide a strong technical basis for future International Electrotechnical Commission (IEC) standards - supporting more robust, accurate, and harmonized DP measurements.
The results will feed into a digital twin combining degradation modelling with monitoring data on humidity and by-products.
SINTEF Energy Research is leading the development of test methods and the digital twin, and will work alongside researchers testing the quality and ageing performance of cellulose insulation.
The model gives power utilities a firmer footing for decisions both at procurement and during operation.
Extending the fleets' lifespan by five years saves 305 million NOK in postponed replacements, rising to 800 million after 20 years.
Industries such aluminium production, rail transport, and paper and transformer manufacturers all stand to benefit due to longer-lasting products.