The north-east German power grid operator E.DIS is currently using Nuventura's first market-ready medium-voltage switchgear Nu1, which uses dry air as an insulating medium. With this pilot project, E.DIS aims to gather operational experience with SF6-free Switchgear.
SF6 is the strongest known greenhouse gas: It is 23,500 times more harmful to the climate than carbon dioxide, and SF6 also has a long atmospheric lifetime. For this reason, there are strong efforts in the industry to reduce the use of this gas, which has been necessary until now, and to end it as quickly as possible in the future.
First commercial grid installation
The objective of the E.DIS pilot operation is to test under real conditions, e.g. current flow at 50% nominal current and to observe and evaluate the behavior during switching operations over longer periods of time. The challenge was to develop identical structural dimensions as conventional switchgear for this range of applications. Furthermore, the newly designed user-friendly switchgear design is to be intensively tested for its practical suitability.
The Nu1 is amongst the first compact GIS on the market for primary medium-voltage distribution networks for voltage levels up to 36 kV that relies entirely on dry (technical) air. Traditionally, in the gas-insulated medium-voltage switchgear for power transmission and distribution, the sulfur hexafluoride (SF6) gas has played a central role as an insulating and quenching medium. The design of the circuit breaker compartment of the Nu1 has already been patented. The type-tested unit also complies with IEC standard 62271- 200 for 36kV rated voltage and 1250 A rated current.
Advanced technical guidance in Design and Assembly by SZM
It was developed by Nuventura in collaboration with SchaltanlagenZubehör Bad Muskau (SZM), providing technical support and advice especially in the field of switchgear technology. In addition, all the early prototypes and the switchgear panels used for the type tests were also assembled in SZM's Bad Muskau facility.
Since mid-April 2021, the system has been in continuous operation successfully at the E.DIS substation in Ketzin near Potsdam. The second installation of this type is currently being carried out in Mecklenburg-Western Pomerania at an industrial customer.