The GB Distribution Code
All DNOs currently operate the same version of the Code, and the Code is maintained by the Distribution Code Review Panel. All modifications to the Code are approved by Ofgem.
Issue 34: Effective from 7 September 2018
This revised version of the GB Distribution Code is to implement the Demand Connection Code (DCC) into the GB arrangements.
The DCC specifically sets harmonised technical standards for the connection of new transmission-connected demand facilities, new transmission-connected distribution facilities and new distribution systems, including new closed distribution systems. It also addresses the performance requirements for new demand units used by a demand facility or a closed distribution system to provide demand response services to relevant network operators - ie both National Grid and the DNOs. Demand response services are an important instrument for increasing the flexibility of the internal energy market and for enabling optimal use of networks. Historically, generation facilities have formed the backbone of providing technical capabilities to network operators. However, demand facilities are expected to play a more pivotal role in the future.
The elements of the DCC that relate to the connection of demand to the transmission system are reflected in the Grid Code, but they have no impact for customers connected to distribution systems.
The DCC deals with five types of demand response services: two which relate to the modulation of real or reactive power for controlling flows of electricity on networks, and three services that relate specifically to National Grid services, ie transmission constraint management and two services for frequency control. Only the two services relating to flow control on distribution networks are picked up in the revisions to the Distribution Code, with the other three services being specified by National Grid in National Grid documentation.
Of course, distribution connected parties can provide demand side response services to National Grid, but in doing so they will be bound by National Grid’s contractual and technical requirements.
As described above, demand sides services for DNOs relating to the modulation of active power (demand) or reactive power are covered by the DCC. However the DCC only applies to those services that are procured by DNOs from new demand units.
The DCC introduces concepts of a demand facility and the demand unit. A demand facility is a customer’s installation where the customer has arranged all or part of the customer’s demand to be modulated as a service to network operator. Services to parties other than network operators (eg energy suppliers) are not covered by the DCC. A demand unit is a device that can be controlled in relation to the contract for demand side services within the demand facility. It is the age of the demand unit that determines whether the DCC applies or not; demand units installed and commissioned before 18 August 2019 are not required to comply with the DCC.
It is therefore quite possible that a single demand services contract with a network operator will include demand units that were commissioned before 18 August 2019 and do not have to comply with DCC requirements, and demand units commissioned after that date that do have to comply.
Copy of Distribution Code Issue 34 can be found here.
Authority decision can be found here.
For previous versions of the GB Distribution Code click here
Distribution Code User Guide
The guide gives a high level overview of the Distribution Code, and is aimed at anyone with an interest in the Distribution Code. It contains information about the regulatory structure in Great Britain and Europe and also provides a simple explanation of the various sections of the Distribution Code.