Introduction To

The Accelerated Loss of Mains Change Programme

The Accelerated Loss of Mains Change Programme (ALoMCP) has been rolled out by National Grid ESO and the UK DNOs (Distribution Network Operators) and iDNOs (independent Distribution Network Operators) to accelerate compliance with the Distribution Code.

The purpose of the initiative is to consider Accelerated Loss of Mains Change Programme (ALoMCP) protection and their settings. The aim being to reduce the risk of inadvertent tripping and reduce system balancing issues by giving National Grid ESO greater latitude with regards to system RoCoF limits.

Your generator will have been connected to the Distribution Network under technical standards that require it to be tripped off at times of network disturbances. This is commonly referred to as the “G59 trip” or “G59 relay”, as G59 was the number of the Energy Networks Association Engineering Recommendation adopted by all DNOs/iDNOs. When your generator was commissioned, the G59 relay would have been programmed with the settings prescribed at the time, then tested and possibly witnessed by the DNO/iDNO.

As more and more distributed generation as been connected to the grid, concerns increase about the amount of generation that can be lost during a system disturbance, due to the G59 relays doing what they were programmed to do. As well as that, nationwide experience has shown that Vector Shift loss of mains protection has not provided results as predictable as had been hoped for.

The ALoMCP programme aims to reduce the likelihood of large amounts of distributed generation being lost on system disturbance by making changes to settings in G59 relays to reduce the sensitivity to tripping, and to migrate any relays still using Vector Shift onto Rate of Change of Frequency (ROCOF).


The Energy Networks Association has published a webpage (link below) to provide more information.


http://www.energynetworks.org/electricity/engineering/accelerated-loss-of-mains-change-programme.html


Bryan J Rendall (Electrical) Ltd (BJRE) have been carrying out G59 related works for almost 20 years, having carried out testing on relays in Orkney as early as 2000 for the emerging wind energy industry. Since then, we have carried out hundreds of installations and tests, witnessed by relevant DNOs. As such, we have the wealth of experience needed to be considered as a “Certified Contractor” as detailed in the above slideshow, and are listed on the ENA website above as a Loss of Mains Protection Support Organisation.

What Can We Do For You?

Having worked in this sector for so long, we understand that changes like this can sound complicated. Confusing terminology like ROCOF and Vector Shift mean very little, when all you want is your generation facility to keep running. As this is our bread and butter, we know what we need to do to help you through this process, before the enforcement element of the programme kicks in in 2022.

In the first instance, we have provided you with this information, which we hope you find useful.

We will help you as much as you need, to get you through the process. We can make the application on your behalf, helping you identify your relay, what its settings are and whether or not they can be successfully changed. That should then be enough for you to make your application.

Later on, should your application be accepted, we can help you with making the changes required including relay replacement (if needed), testing the new settings / relay and submitting the evidence on your behalf.

What Do I Need To Do Next?

Now that the ALoMCP portal is live, the application process is next, and if you would prefer us to take care of the application for you, please fill in the form below with as many details as possible.

We will help you as much as you need, to get you through the process. We can make the application on your behalf, helping you identify your relay, what its settings are and whether or not they can be successfully changed.


To register directly via the Energy Networks Association portal, please click here.

GDPR - As a business to business communication, this letter is outwith the scope of the General Data Protection Regulations. Aside from that, we are happy to let you know that we hold no details about you other than those that are freely and publicly available on the Renewables and CHP Register. We will not contact you again in relation to this project unless you actively respond to us and give us permission to do so. We will not pass your details onto anyone else without your permission. If you provide us with any additional information over and above that freely available on the internet, we will ensure those details are kept fully in accordance with the GDPR.