Loss of Mains protection requirements

Engineering Recommendation (EREC) G59 Issue 3, Amendment 7 was published 1 September 2019: ENA EREC template v1.0 (dcode.org.uk). This included a modification to section 10.5.7.1 Protection Settings to apply a Rate of Change of Frequency (RoCoF) setting of 1 HZ/s with a definite time delay of 0.5s retrospectively to all generation <50MW. Generation owners were given 3 years to check their Loss of Mains (LoM) protection settings and where not compliant, take action to meet compliance by 31 August 2022.

A declaration of compliance is required if your generation:

1. Was connected under EREC G59 prior to February 2018 (or prior to July 2018 if the site only has type tested inverters and no separate LoM relays); and

2. Operates in Long Term Parallel mode with the distribution network.

If work is needed, does it need to be witnessed by UK Power Networks?

Generation sites can self-certify if the required work on site is a settings change or setting disablement to an existing relay protection device. If the required work on site is a protection device replacement or LoM firmware/logic relay update, you will need to request for us to witness the changes.

Acceptable evidence:

A G59 test certificate – EREC G59/3-7 13.3 Generating Plant Installation and Commissioning Tests.

Enforcement process

Enforcement action will be taken for instances of non-compliance with the Distribution Code. Generation owners have 26 weeks from the date of the first notification to ensure that generators are compliant with G59 Distribution Code regulations. The process can be found here. 

Help

1. You can use the self-serve tool here: https://futureproofyourpower.co.uk/ to help you.

2. If you have any questions, please email G59ProtectionSettings@ukpowernetworks.co.uk. 

How to declare compliance

Please complete a Declaration of Compliance form and submit it to G59ProtectionSettings@ukpowernetworks.co.uk.