VolkerStevin is one of three companies on National Grid's Substation Flood Defence Framework which provides flood defences to over 38 sites across the UK. This four year, £80 million framework sees VolkerStevin protect National Grid assets such as Substations and power distribution centres which are located in flood risk areas and local flood plains.
The purpose of the works is to ensure that National Grid sites remain safe and operational during flood events with no loss of supply or risk to system stability. The individual design and build projects are issued on an Early Contractor Involvement basis and VolkerStevin works with its Designer to determine the most appropriate method of defence.
The sites are live substations and elements of the work require working near to live overhead conductors and high voltage plant. We have fully trained site teams with TP144 trained Site Managers. Key staff and operatives are Competent Person trained to hold National Grid safety documents to ensure works align to National Grid's Policies and Procedures.
A number of projects are currently underway on the Framework; an example includes the design and construction of new flood boundaries at Stella South Substation, which is a live, operational 132kV Substation located adjacent to the River Tyne in Newburn. Works comprise the design and construction of both a hard flood barrier and a soft defence earth bund to protect the full high voltage yard and to ensure that safe access and continuity of supply can be maintained at the Substation for a 1 in 1000 flood event. To reduce our ecological impact and disturbance to the local community we are using site won material in the flood bund to reduce the amount of waste materials being sent off site and to minimise vehicle movements.
Similiar works are being undertaken at Aberthaw Substation where we are leading the design and construction of a 2.4m high piled foundation concrete flood wall to protect the 132kV Substation bulding, high voltage yard and back up diesel generator yard. We are also constructing a 1.4m high concrete flood wall to protect the 275kV Substation. Works comprise the design, construction and installation of floor doors, gates, drainage and pumping stations.