Electricity substations explained with Lego

One of the transmission grid’s key assets: a Terna engineer set about building it with toy bricks.

You can build anything with Lego bricks. From the simplest figures to the most ambitious projects; over the years this Danish toy has been part of everyone's childhood and has covered a wide range of themes. Entire cities, racing cars, life-size human figures, a faithful replica of the Titanic, a cherry tree and even part of a Terna electricity substation have been built with Lego.

The model was assembled by Giuseppe Pelliccione, who works in the Technology and Plant Development (RIT) department of the national transmission grid operator. Electrical engineer Giuseppe is familiar with electricity substation technology and components through his job, so he had no problem replicating them in a model made with the iconic bricks: a fun but effective way to give a “bite-size” explanation of how a substation works in the real world.

The 150 kV section of a transformer bay. On the left, part of the 150 kV busbar system; on the right the 150/380 kV transformer. In the middle, the switching equipment, instrument transformers and kiosk (photo by Terna)

Not everyone is familiar with what goes on in these installations or knows how important they are in the electricity supply chain.

Domestically, Terna manages the electricity transmission grid, which consists of numerous high voltage lines: the substations are the very nerve centre of this network. The lines carrying the electricity reach the substations and from there it is redistributed to other lines and in some cases transformed.

There are switching, conversion and transformation substations, inside of which the various high-voltage components perform a series of diverse operations. The substations are all modular in structure with several sections, which are in turn made up of a busbar system and a set of associated components called uprights or bays. The busbars are the core of the substation and consist of a trio of conductors, which connect to the bays by means of bar sectioners. The bays are made up of switching equipment (circuit breakers and disconnectors) and instrument transformers for voltage and current.

- switching substations connect power lines of the same voltage level and distribute the electrical energy between them;

- conversion substations convert voltage from alternating to direct current, and vice versa;

- transformer substations (the template for Pelliccione’s Lego version) “convert” the electricity, i.e. they bring it from one voltage level to another by using high-voltage transformers that connect together via busbar systems at different voltage levels.

A high-voltage transformer being filled with mineral or vegetable oil. High-voltage transformers use mineral or vegetable oil internally to ensure that the live parts are electrically insulated (photo by Terna)

High-voltage transformers are electrical devices that convert electricity from transmission level (for long-distance transport) to sub-transmission level (for switching to load centres or for the withdrawal of electricity from production centres); for example, in Italy it means going from 420 kV to 150 kV, and vice versa. This allows electricity to be transported as efficiently as possible, because (for the same amount of power transmitted) the higher the voltage, the lower the grid losses are along the power lines. Each transformer needs a series of auxiliary devices in order to function and is immersed in a large quantity of mineral or vegetable oil, which is periodically withdrawn, processed and pumped into the machinery; as the image shows, the operation involves a tanker truck, oil treatment units and Terna technicians.

Technical personnel are essential for all equipment maintenance and replacement in the electricity substation. Although it is an independently functioning unit, it needs constant and regular monitoring. In addition to busbars, bays and high-voltage transformers, there is a set of switching equipment and instrument transformers that send the electricity on its way to the primary distribution cabins.

A substation also consists of line sectioners and busbars, which create reliable insulation and ensure continuity of current in the “closed” position, and high-voltage breakers which open and close the power circuits. The voltage and current transformers (shown being replaced in the model) respectively transfer the system voltage and current amplitude to the measurement and protection circuits.

A current transformer being replaced by an increased reliability unit, insulated with SF6 gas. On the left, the high-voltage circuit breakers. Current transformers and high-voltage circuit breakers use SF6 gas internally to ensure that the live parts are electrically insulated (photo by Terna)

This equipment is all remotely connected to Terna control centres, giving technicians an overview of what is happening even though they are not physically on-site: if something is not functioning properly, they get immediate notification.

The kiosks are pre-fabricated reinforced concrete structures where these control functions necessarily take place. They contain all the automation system peripheral components and devices such as computers and routers.

Information systems allow the operators in charge of the substations to remotely check for faults or anomalies, monitor the status of assets and also to plan routine inspection and maintenance work.

The former controls allow staff to monitor the condition of the substation components to make sure there are no signs of wear or malfunction that could affect their normal operation. The latter controls serve to keep the equipment in good working order. They are performed periodically or following a fault or a post-control report from the technicians – who themselves are faithfully reproduced in the Lego version along with all the other components.

Control operations in the transformer bay kiosk. For control and maintenance work, Terna personnel can switch equipment controls on-site and perform operations on the circuit breakers and disconnectors of a bay (photo by Terna)

BEHIND THE SCENES. Giuseppe Pelliccione is an electrical engineer, but outside of work he has two great passions: modelling and his nephews. He has been an avid modeller, working with paints and glue for years as a way of keeping his hand in with the creative vocation he nurtured before embarking on his engineering studies: classical high school, conservatory and drawing and painting courses in the studio of his uncle Augusto Pelliccione – a famous Abruzzo painter and sculptor, recently deceased. The nephews came along later, along with his love for his wife and family, originally from Poland. It was there that Giuseppe met Julek and Miriam. He quickly became their favourite uncle, despite the difficulties caused by the language barrier. To win them over, he used toys and above all, Lego. Miriam, herself a huge Lego fan, became increasingly curious and started asking her mother what her uncle did for a living. But how could she explain to a Polish second-year primary school child with a passion for building bricks what goes on in electricity substations? Lego was the only way to do it.

To find a way forward, Giuseppe decided to do some research online. He soon discovered that Lego is no longer just a kids’ toy, but something that thousands of adults are passionate about. The company itself identifies them as AFOL ("adult fans of Lego"), and they do in fact constitute an important market sector, given their extended financial scope. The home base for all fans is Bricklink.com, a site created as a secondary market where you can buy individual parts of any kind and where you can also design your own builds on the computer, using the free Studio software. It is a blank canvas where you can create a blueprint for any object – with no limit on the number of bricks. The programme then generates the “shopping list” and instructions for the design.

Giuseppe started from there and it took him a month to obtain a perfect model, designed for play and to help explain to his grandchildren what his work at the substation involved. Finally, he bought all the parts and assembled the whole thing so that he could take some pictures; the health emergency was in full swing and his grandchildren were unable to come to Italy. The grandchildren really loved it – as did his Terna colleagues, who were able to show the pictures also to their children. The work also garnered some success on the website: his Lego transformer was selected for the “Staff Pick” award of the week in September 2020, and his model of an Austrian castle received the same award in February 2021.

Giuseppe's engineering precision is evident in the details, which are realistically reconstructed using existing Lego pieces; he sifted through old sets, selecting and combining specific components to be as true to reality as possible. This was surely proof that, along with electricity, the artist's creativity runs in his veins.

Inspection and maintenance work on the Buchholtz relay of a high voltage transformer. The Buchholtz relay is a primary protection device in transformers equipped with an oil conservator. On the left are the transformer bushings, which connect to the electrical conductors; on the right is the oil conservator (photo by Terna)