| Transmission & distribution


Right: Hitachi Energy’s 420 kV EconiQTM SF6


-free circuit-breaker


the use of fluoronitrile based mixtures as an alternative to SF6


May 2021, p 20). These mixtures and the compactness and performance they deliver are a key feature of EconiQ.


The 420 kV circuit-breaker is a fundamental enabling technology for further expansion of the SF6


-free HV portfolio, and will be used in both dead tank breaker (DTB) and future GIS applications. The EconiQ 420 kV DTB and GIS are expected to be released at the end of 2022, on track with the Hitachi Energy roadmap for SF6


elimination.


Hitachi Energy plans to install the world’s first EconiQ 420 kV circuit-breaker by mid 2023, as part of an SF6


breaker, also a world first. This installation will be for Eversource in New England, USA,


-free 420 kV dead tank


(see Modern Power Systems,


How do the dimensions/footprint/performance of your fluoronitrile based 420 kV circuit breaker compare with SF6


based predecessors?


The footprint and dimensions are very similar to those achieved with SF6


. The new circuit-breaker has in all regards


the same performance and the same reliability as the SF6 equipment.


equipment (eg DTB, GIS)? The next steps are to complete the type tests and start commercial production. Thanks to the common platform approach, the 420 kV circuit-breaker will be used in both 420 kV dead tank breakers (DTBs) and 420 kV gas-insulated switchgear (GIS), which are expected to be released before the end of this year, as per our 2021 roadmap. As the technology is scalable, it will be also utilised with some adaptations in other products lines and voltage levels.


What are the next steps in terms of your EconiQ roadmap, and how will the 420 kV circuit breaker technology benefit/be used in other SF6


-free


You have suggested that the industry is likely to converge on fluoronitrile mixtures. Are we beginning to see signs of that? Yes, in Europe, two out of three major industry players are already using fluoronitrile gas mixtures to replace SF6


.


There are also several manufacturers in China and Korea using the fluoronitrile gas mixture. There are IEC standards published or under preparation covering the fluoronitrile gas mixture. The auxiliary and gas handling equipment for fluoronitrile gas mixtures are commercially available from several manufacturers. Hence, there is already an industrial ecosystem around this technology.


in the EU, how future proof is fluoronitrile based technology? We believe that the technology based on the fluoronitriles is the future and the regulations will reflect that. It is the most


In the context of tightening regulations on SF6 , eg


practical and scalable of solutions available today for voltage levels above 52 kV, and is the only technology to enable a fast phase-out of SF6


while ensuring the transmission grid


reliability that is essential to the energy transition. We are of the opinion that regulations should be technology-centric and take into account the overall environmental footprint of the entire switchgear and the substation. High-voltage SF6


-free solutions that do not use fluoronitrile


mixtures are larger in size, resulting in higher impact on the environment as more raw materials are used, and require larger spaces and buildings. The compactness in gas-insulated high-voltage equipment is achievable only with the high dielectric performance that comes from using small quantities of fluorinated gas in the gas mixture. This is a straightforward consequence of fundamental science that is acknowledged by all experts.


After the European Commission published the proposal


for possible future F-gas regulations, all stakeholders were invited to comment. Almost all of the relevant high- voltage stakeholders commented in favour of introducing fluoronitrile based solutions. ENTSO-E (European Network of Transmission System Operators for Electricity), the association representing 39 European transmission system operators from 35 countries, wrote in their statement: “TSOs absolutely need technologies with GWP>10 to avoid delaying the implementation of their SF6


strong endorsement of fluoronitrile-based technology.


Is the fluoronitrile gas mixture applicable to the existing fleet? Insulating gas with fluoronitrile gas mixture is very versatile and additionally enables retrofill of existing gas-insulated lines of SF6


equipment. This helps prevent future SF6 gas


leaks in the large installed fleet without exchanging primary equipment. Together with National Grid UK, we have successfully energised a world first pilot in Richborough, UK, replacing SF6


in installed high-voltage gas-insulated lines. EconiQ Retrofill is now part of our high voltage portfolio.


phase-out strategies.” This is a


www.modernpowersystems.com | September 2022 | 17


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