Successful milestone for ESB Networks Projects

The end of March 2007 marked another successful milestone in the 110kV GIS Substation Construction programme being delivered in the Dublin area by ESB Network Projects. Bryan Crowley, ESB Network Projects tells us about this significant project.

On the weekend of the 24th/25th March 2007, the Pottery Road 110kV/MV substation in Dun Laoghaire was fully energised and additional medium voltage (MV) capacity was made available on schedule to the adjacent Pfizer Pharmaceutical Plant. This was a critical, high profile project which facilitated a major expansion in Pfizer's operations at their Dublin site.

What is the GIS programme all about?
The 110kV Gas Insulated Switchgear (GIS) station programme has been underway in the Dublin area for six years and has proven to be a successful model in providing critical capacity to cater for large, dense, urban MV loads.

Each substation involves the installation of two 20 MVA indoor 110kV/MV transformers with associated switchgear and equipment. Initially, this type of substation was developed to cater for a number of large highload 'web-farms' that were planned in the Dublin area where a shorter construction period was required.

However, with the booming construction sector taking hold all over Dublin, these substations became an ideal solution in major developerdriven projects where large residential/commercial projects were being progressed

A common implication for these projects was that the site being made available to ESB for a substation was relatively small due to land prices while simultaneously, the timeline for making supply available was relatively short. Therefore, a conventional indoor or outdoor 38kV or 110kV substation was not suitable and hence the GIS model was developed.

What are the key features of a GIS substation?
The key feature of the GIS substation is that the 110kV switchgear comes in a very compact, self-contained unit. The 'live' working parts such as busbars, disconnects etc. are completely enclosed and 'gasinsulated' within the external steel structure.

Typically, an entire busbar is approximately seven meters long, three meters deep by two meters high. Therefore, the obvious benefit is that the size of the substation footprint can now be drastically reduced and the length of the programme can be cut because a lot of the equipment is assembled and tested by the manufacturer offsite.

What is the extent of GIS construction and installation?
GIS substations have now been built in Artane, Kilmore and College Park on the north side of the city. On the south side, Taney GIS substation in Dundrum was primarily built to meet the huge load demands presented by the construction of Dundrum Town Centre in 2005. Other substations have been built to cater for the huge developments in the Docklands area.

What has made the programme so successful?
A key feature of the construction of these substations has been the partnership between ESB Networks and the turnkey electrical contractor, ABB, who have completed the electrical installation on all of the GIS substations up to now. Both parties have also worked very hard to ensure that the highest safety standards are met on each of the projects.

The ESBI GIS Team has played a major role in the design process and engagement with both the civil contractor and ABB on day-to-day issues.

Network Projects East Transmission in Inchicore has also played a key role in delivering the 110kV loop-in cables and connections on time, sometimes in very challenging circumstances. They have also been key to the provision of remote end works and final handover of the substation from ABB.

A significant amount of engagement is also required with the Northern Distribution Control Centre (NDCC) in Leopardstown and ESB Telecoms on the planning and management of network outages, coordination of substation switch-in and the provision of SCADA communications and Fibre Optic Connectivity.

Also, a new feature of the management of these projects has been the coordination of the supply offloading and MV connections from the substation. This involved engagement of the project team with Asset Management and the local MV Operations and Network Services staff in Dublin Central and Dublin South to ensure a smooth handover and connection process.

What are the challenges ahead over the coming years?
Looking ahead, there doesn't appear to be any let-up in the demand for additional 110kV/ MV capacity in the Dublin area. Civil works are already underway for GIS substations at Pelletstown, Leopardstown and Poppintree, the latter to facilitate the proposed Ikea Development.

Construction is planned to commence on further substations near Trinity College and Heuston Station later in 2007.

Outside Dublin, GIS technology is the preferred choice for the new Ballyadam project in East Cork, which will supply the major new Amgen Pharmaceutical facility and for the Baroda project, Newbridge to cater for the increased load at the Wyeth plant. In Limerick, construction work will begin in May 2007 on a new 110kV/MV GIS substation at Singland to facilitate a major commercial / residential development.

Looking ahead, with ESB Networks planning to introduce additional technologies, including Mixed Technology Switchgear (MTS), there should be a broad range of suitable substation switchgear options available to meet the needs of major 110kV /MV developments nationwide well into the future. EM