To facilitate the connection of the new Beauly Denny overhead line (OHL) to the existing network a new 275/400kV substation is being constructed at a site near Dunipace, Denny.
The substation is in an area where a number of existing overhead transmission lines converge and therefore forms a key hub in the existing electrical network.
Substations are required on the electrical network to serve two key purposes. They transform electricity to the lower voltages which can supply homes and local businesses and they can switch electricity flow over different routes to supply different areas of the country or provide backup in the event of a fault. Substations generally consist of a control building and a fenced compound containing electrical apparatus, including transformers, switchgear and terminal towers.
Construction of the new Denny substation commenced in late 2012 with the upgrading of a 2km stretch of the (C64) unclassified road from the main junction onto the A782, west of Dunipace up to the substation site. The road was widened and passing places installed to minimise disruption to road users by any additional traffic caused by the project. Use of this and surrounding roads has and will be managed via an approved traffic management plan and will continue to be monitored and implemented in consultation with the Local Roads Authority.
The land at Denny forms part of an existing habitat of raised peat bogs. As part of the project SP Energy Networks (SPEN) undertook an innovative process of peat deposition to ensure that peat removed from the site, to facilitate the substation would be used to improve habitat and deliver an overall ecological benefit on the remaining area of mire. This process of habitat creation has been largely completed on site and will continue to be monitored and managed, in accordance with an approved habitat plan by the SPEN environmental team in consultation with SEPA and SNH.
Work on the physical concrete platform which provides the base for the substation is also complete, this allowed mechanical and electrical infrastructure to be installed on the site and this work will continue over the coming year. In addition to the substation works, foundations for overhead line towers has started. The creation of the concrete foundations/tower bases, together with the erection of OHL towers themselves will progress through to October 2014.
What will be happening at Denny substation in 2014?
- The environmental team will continue work on the management of the peatland habitat at Torwood Mire, adjacent to the substation site. This will involve small teams of environmental professionals on site conducting visual surveys and non-invasive testing.
- SPEN contractors will be on-site installing electrical and mechanical infrastructure on the existing concrete platform. Electrical apparatus will be arriving on site through the spring and summer of 2014, sometimes on large, specially adapted transporters under agreed traffic management. This apparatus will be unloaded and assembled at the platform with the process being completed by the end of 2014.
- The formation of OHL towers will see concrete foundations being laid, these involve deep foundation concrete piles being delivered to the site in late 2013 through to the first half of 2014 and once installed steel lattice towers will be erected in sections. It is intended that this phase of construction will be completed by late 2014.