Revision to EREC G99/1

The ENA document EREC G99/1 governing the connection of embedded generators to the (other than domestic and similar projects <16A/phase) has been revised, with a new version coming into force at the beginning of September 2021.

The latest version can be freely downloaded from the Distribution Code website (or you can click here for a direct link to EREC G99/1-8)

The revision notes list this as a "minor technical modification". However, there are some noteworthy changes that affect the solar and energy storage projects we're involved in:

• There are now additional references to cyber security measures
  
• Type-testing of equipment can now be carried out for families of similar units using the same control
  
• Requirements for the accuracy, and other specifications, of instrument transformers and meters used for fault recording and
  
• New considerations for systems designed to normally operate as an independent island, but capable of paralleling with the DNO's network
  
• Changes and new tests to ensure stability under no-fault conditions
  
• Changes to the information required and the format of standard application forms
  

The previous EREC G99/1-7 was only published in August. It, too had some interesting changes, notably forewarning in the Foreword that energy storage units are likely to be required to export, or at least stop importing, during underfrequency events; a technical description of what this might look like (currently options) are included. The Foreword suggests that it'll be confirmed and become a mandatory requirement in 2022.