Field tests of a vacuum circuit breaker in the 110-kV high voltage grid

Abstract The ban on the use of the greenhouse gas SF 6 as an insulating and extinguishing gas in equipment and switchgear under the EU’s F‑Gas Regulation requires the use of alternative technologies. This article shows the findings of short-cicuit and operational switching tests of the first installed vacuum circuit breaker in the 110-kV grid in Austria. The focus is to assess the performance during the switching operations and the discussion of the occurred phenomena. Transient phenomena can only be recorded with the use of high-bandwidth CR dividers for voltage and fiber-optic sensors for current measurement. The article investigates a symmetrical terminal fault with multiple reignitions in detail and discusses the switching of a no-loaded transformer. All operational switchings including fault clearings are standard conform and offer valuable insights into the dynamic response of the grid. As result the circuit breaker has been successfully commissioned and is now in operation in the 110-kV coupling bay.