icubed consulting designs the civil works, structural foundations and steel-work for wind farm and solar farm substations. A critical component of a substation is the transformer (no, not the Autobot kind!).
Transformers are everywhere and form part of an electrical circuit. A transformer’s primary role is to either step-up (increase) or step-down (decrease) circuit voltage. For instance, charging your phone from a 240 V power socket requires a small transformer built into the plug to decrease the voltage to around 5-12 V.
Transformers are also found in most appliances, power plugs, on street poles, in industrial buildings and as mentioned; in substations – usually featured at the centre of the substation.
As a transformer alters the electrical load conditions, it gets hot – very hot. Larger transformers (like the one below) use oil for cooling.
icubed’s Ettienne Bruwer, Sione Manu and Brett Rieker are currently working on civil and structural design for the Dundonnell substation comprising of 2 large transformers. The larger transformer weighs 210 tonnes and has an oil capacity of 68,200 litres.
As with most substations with more than one transformer, a firewall is required between them. The firewall Ettienne and Sione are designing for the Dundonnell wind farm substation will be a steel reinforced concrete wall at 9.0 m high x 0.35 m thick.
icubed also designed the footing, plinth and bund system to host the transformer. Interestingly the footing design is governed by the loads imposed during the delivery of the transformer – not the operational forces. The footing can be expected to take up to a 100 tonne point load over an area of 0.25 m² during the installation process. The plinths need to be ‘super-flat’ meaning deviations not greater than ±1 mm to ensure the integrity of the transformer.
Bunding calculations are a balancing act. Designs need to; consider the timely discharge of rain captured during large storm events, ensure retention of any oil spillage and provide safe egress out of the bund.
The following images are of a smaller transformer delivery and the 7.0m firewall icubed designed for the Ararat wind farm substation nearly 4 years ago.