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  • Loss of Mains (LoM)

  • Loss of mains protection is used to stop any damage when problems occur on the electricity distribution network.  Methods used in the past can disconnect generation when it is not necessary to do so. The effect of this more often than not happens when more renewable generation is running and the costs of trying to stop any disruptions are paid for by the consumer and electricity industry.   Changing loss of mains protection will therefore deliver a step change in how the electricity system can be operated and will allow more low carbon power to flow at lower cost.
    Distribution Network Owners (DNOs), Independent Distributuion Network Owners (IDNOs) and National Grid ESO are joining together through the ‘loss of mains change programme’, led by the ENA to accelerate compliance with new requirements in the Distribution Code.   These requirements highlight that the current protection settings required for any new generation connecting to the network must now also be applied retrospectively to all existing generation with loss of mains protection.

    This means that owners of generators fitted with older forms of loss of mains protection will need to make changes to their protection by May 2022.  Support will be available – please view the ENA website for details - click here .  The LoM change programme allows generator owners to apply for a financial contribution to help them get the necessary work done.  Their details will be entered into a new portal (through the ENA) to help with this.  


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