O’HARA ENGINEERING SERVICES is one constructors with the vast majority of its public contracts being carried out at 110kV. The transmission network sub-stations at 110kV in the Republic of Ireland are currently controlled by Eirgrid and under the remit of ESB Networks. These 110kV are built to provide services to small generation plants, heavy industry, commercial industry, transport and domestic users on the distribution service network. The locations of these stations can be diverse from the mountain top for connection of large wind generation stations, where generation time is money to the city centre financial districts where security of the electrical supply is as important as the transactions that take place.
Hybrid Outdoor switchgear is generally the solution used by distribution service operators in outer urban centres where sub-stations are required. The line/transformer bay arrangements are approximately 1/3 of the size of a standard outdoor Air Insulated sub-station. This offers two main advantages over other types of station, reduced site size and thus reducing site purchase values and secondly the switchgear is outdoor negating the need for expensive and time consuming sub-station building construction.
110kV HIS Substation, Salthill, Co. Galway