EirGrid, as a Transmission System Operator (TSO), plans, manages, develops and operates the national electricity transmission grid at 110, 220, 275 and 400kV across the island of Ireland.
EirGrid develops and maintains Transmission Investment Policies setting out the acceptable standards and regulations for transmission developments.
Below is a non-exhaustive list of policies that may be of interest to customers seeking connections. EirGrid considers it appropriate to engage with stakeholders when the development of new or changes to pre-existing technical standards and policies pertaining to transmission equipment and installations are proposed which could result in a significant increase in customer project costs or planning requirements. Following conclusion of a period during which stakeholder feedback was invited by 26 February 2021, EirGrid has finalised its engagement process for development and update of technical standards and policies which sets out the steps that EirGrid will follow in these circumstances here.
Transmission Policy Documents
EirGrid maintains and develops technical standards, including functional specifications and standard drawings that are available to assist Customers proposing to connect to the Irish transmission system. These technical standards govern the design and construction of new transmission assets namely transmission substations, cables and overhead lines as well as providing guidance when developments are proposed in proximity to existing transmission infrastructure.
Below is a non-exhaustive list of commonly used technical standards for demand and generation customers to consider when developing their connection projects and associated planning applications.
Standard Layout Drawings:
Standard Single Line Diagrams:
It should be noted that requirements can change based on new technologies, safe working standards or lessons learned during construction, operation and decommissioning. There are a wide variety of potential transmission connection solutions. The standard layout drawings provided here are concept designs of the most commonly acceptable solutions and are provided for guidance only.
AIS substations comprise of open-terminal air –insulated switchgear, whereas GIS substations comprise of metal enclosed gas-insulated switchgear. In GIS substations the switchgear is located in a building. In the case of AIS substations the switchgear is generally located outdoors.
Detailed project specific documentation is provided to applicants who have executed a connection offer with EirGrid.
EirGrid will work with customers and provide technical assistance with their planning drawings to incorporate technical feedback in advance of finalising their planning submissions. Customers are encouraged to check that they are using the most up-to-date information.
For further information on the connection offer process, please refer to this page on becoming a customer.
For customers currently engaging with EirGrid in the connection offer process, further detailed specifications and standards can be made available on the EirGrid Extranet page. (Requests for access to the EirGrid extranet page for Transmission standards should be submitted to firstname.lastname@example.org.)
Information provided to customers on this website contains general and technical information, which is subject to change from time to time without notice. EirGrid makes no warranties or representations of any kind with respect to the general and technical information provided or the content of any other document or website referred to on this website. EirGrid cannot determine any proposed connection methods until the formal connection application process is completed. Until an application is submitted and the relevant detailed studies and an executed connection agreement are complete, EirGrid will not be in a position to confirm specific technical details. Customers should not act or refrain from acting on the basis of any information provided without seeking appropriate professional advice.
Use of the information provided is solely at the user's own risk. EirGrid does not accept liability for any loss or damage arising from use or reliance on the information provided.