Tell us about the early design brief
Kings Yard Primary Sub-station was developed as part of the Olympic Park. A number of structures were required to house infrastructure for a period during the Games and in legacy mode after the Games. The outline planning applications stated that they were “to be designed with attention to the aesthetic consideration as well as to achieve value, bearing in mind environmental impact, maintenance and whole cycle cost.” The electricity substation was the first utility building to come forward for detailed planning permission and the design that was developed would influence other local utility buildings.
What challenges did you face along the way?
One of the first design issues to overcome was geometry. At that time the site was extremely tight and boundaries were being determined as design and construction was underway. There was a sight line towards the Hertford Union (Duckett’s Canal) that needed careful consideration as every time the building moved the elevations had to change.
Delivery of plant was a key consideration both during the initial installation and for the future. Transformers came on a large low loader – the trailer unit by itself had 24 wheels on six axles and was pulled by a four-axle tractor unit weighing 40 tonnes.
There had to be room for these vehicles into the site and for emergency services to be able to get past the vehicle in the unlikely event of an accident on site. Similarly, the more common vehicles bringing in equipment and servicing had to be able to drive in and turn around within the site confines.
Cabling a sub-station is an art all by itself. There had to be a certain separation between the cables. For example, the 132kV cables needed a large bending radius (2.5m), while the 11kV cables could be bent tighter but their sheer number meant that heating issues had to be carefully considered. In a fault scenario it was possible, particularly in the 132kV network, that extremely large currents could flow through the cables leading to a magnetic effect which would result in loads on cleats and supporting steelwork equivalent to 600kg.
What about specific design challenges?
Designing a cabling solution was a major exercise, with many of the cables which ran into the sub-station having to be placed in a specially installed under-railway-track crossing (UTX) consisting of seven thrust bored steel tubes to house 11kV and 132kV cables.
How did it feel to be involved in such an important British project?
Utility buildings are vital to society but rarely get recognition. We hope that these projects will encourage all utilities service providers to promote innovative design and best practice in the future. Andrews Associates were delighted to work as part of the team putting this project together.