Good reasons behind growing popularity of modular substations

Modular substations are fast becoming the format of choice in many applications from industrial sites to data centres to mining and the oil and gas sector, delivering benefits such as quick deployment, lower installation costs and more flexibility.

"The trend towards modular substations is now well established in many sectors – and for good reason," says Trafo Power Solutions Managing Director David Claassen. "There are many different options and designs, from shipping containers to larger or more purpose-designed E-houses."

Standard shipping containers – in either 20 foot or 40 foot configurations – provide an economical and compliant format for substations that must be transported via land or by sea, he notes.

The dimensions facilitate cost effective logistics, and generally ensure quicker availability of on-board space when arranging shipping on container vessels. Indeed, the containerised concept was where the modular idea originated, as it could be moved around easily.

"More recently, though, we have seen the concept develop into much larger substation sizes – but the benefits remain," he says.

"These can generally be constructed quite simply with structural steel with fire-rated insulation to enhance the safety rating of the installation."

When compared to constructing a normal building on site, with all the related civils work, the modular option quickly shows a range of benefits. Especially in remote locations, any building work can become complex, costly and time consuming. These costs include transporting various building materials to site over long distances, as well as finding and employing scarce skills and supervision.

"This traditional route also involves taking all the electrical components to site – and then installing, testing and commissioning them in conditions that are often less than ideal," he explains.

"By contrast, a modular substation can be constructed for the most part in a fully-equipped factory, which is more conducive to quality and speed."

Once shipped to site, there is minimal work to be done before the modular substation can be commissioned and put to work.

Modular substations can also be designed with state-of-the-art technology for improved reliability, easier maintenance and reduced running costs.

He highlights that dry-type transformers add considerable value to the modular substation concept, as these can be installed inside a container or e-house. Claassen explains that the safety levels intrinsic to dry-type transformers mean that they do not need a separate enclosure outside the modular structure.

"Effectively, the dry-type transformer is just another aspect of the electrical arrangement in a substation that can be readily modularised," he says. "For safety and other reasons, an oil-filled transformer would still need its own infrastructure due to the risk of fire, explosion or oil spills."

He highlights that this is counter-productive to the modular philosophy which makes this format of substation so popular. By using a dry-type transformer instead, the installation can avoid having a separate transformer bay, fire protection and suppression facilities, and outside cabling. With a dry-type transformer inside the substation, there is also a reduction in the overall footprint size.