Transformers are rigid and strong assemblies. But when extreme pressure builds up inside the electrical equipment, it can, in rare cases, lead to tank rupture, becoming a serious safety and environmental hazard.
TXpandTM is a comprehensive solution that makes transformers more secure, similar to how crumple zones in cars redistribute the force of a collision and protect passengers.
The technology is based on extensive analysis and modelling. It is built to make the most rigid areas within a transformer flexible, the weakest ones stronger and include rupture points – to control the most unpredictable failures. Dry bushings and a conservator shutter valve complete these protective measures in addition to standard features such as pressure relief devices.
ABB TXpandTM was developed in close partnership with Hydro Quebec, a Canadian utility with over 2,000 power transformers in operation reaching up to 765 kilovolts (kV). The concept was jointly tested at the utility’s facilities, creating a unique reference in the industry.
A 200 mega-volt-ampere 330 kV transformer tank was put to one of the harshest internal overpressure conditions in transformers connected to networks of up to 765 kV. Air was injected at 200 times the standard atmospheric pressure, equivalent to a major internal fault. It released 20 mega joules of energy.
The test was successful. The tank expanded and absorbed the energy exactly as predicted, validating the concept of turning potential safety hazards into manageable events. It can protect the environment by preventing oil spills and pollution.
“Computer simulations still need validation and the value of the full-scale real-life test on the TXpandTM technology proves it as a risk mitigation solution,” said Krzysztof Kulasek, Global Product Manager, ABB Transformers. “Power transformers, today, are safer to operate thanks to TXpandTM. The technology is an example of cooperation between manufacturers and users, applying innovation, technology and know-how to enhance reliability and safety of critical systems.”