Transmission Interface Arrangements

The Transmission Interface Arrangements (TIA) outline the terms and arrangements for interactions between SONI and NIE Networks. The TIA is designed to facilitate the efficient operation, planning, development, construction and maintenance of the transmission system.

SONI is the independent Transmission System Operator for Northern Ireland and under the conditions of our transmission licence, we are required to plan and operate the transmission system in accordance with the requirements of the TIA.


TIA Documents

The latest approved version of the TIA can be found here.
Schedule 1 – February 2023 can be found here.


TIA Subsidiary Documents
TIA SD 1- Need Case
TIA SD 2- Option Appraisal
TIA SD 4- Route Corridors
TIA SD 5- Route Alignment and Site Locations


TIA Modifications

28 July 2023:
The TIA Amendment Report can be found here.

5 April 2023:
The TIA Proposed Amendment Consultation Notice can be found here.

The Section S modification proposed by NIE Networks can be found in the Proposed Amendment Report here.