The NEW Requirements for Loss of Mains G98 G99 G100

The Accelerated Loss of Mains Change programme requires owners of electricity generation across Great Britain to change asset settings following an update to the Distribution Code.

Through the programme, generation asset owners will help to avoid or reduce unnecessary tripping on the system, making the country’s already secure, reliable power system even stronger. The programme is a partnership between Energy Networks Association (ENA), National Grid Electricity System Operator (NGESO) and the local and independent electricity network companies (DNOs and IDNOs).

After many months of preparation, up to 50,000 owners of generation assets connected to local electricity networks now need to change these asset settings to comply with the update. This covers all forms of generation – from solar photovoltaic and wind farms to combined heat and power installations and anaerobic digestion plants.

As you know, the Distribution Code is a set of standards which govern the connection to and use of local electricity networks across Great Britain. The new Loss of Mains protection requirements, as they are known, are outlined in the amended Code under Engineering Recommendation (EREC) G59/3 Amendment 7.

Limited funding is available to support the process of changing asset settings, by prior agreement. Generation asset owners are asked to register their interest now via the portal on ENA’s website. Owners are required to change their settings by September 2022 and may face enforcement after this date.

Settings may need to be changed on generation assets which meet the following criteria:

  • Non-type-tested assets installed before 1 February 2018.
  • Loss of Mains Protection is provided by Rate of Change of Frequency (RoCoF) or Vector Shift.
  • Operates in parallel with mains electricity.