Switchgear, what is it and what elements compose it?

Centros de transformación y aparamenta eléctrica

Electrical switchgear, or switchgear, encompasses a wide range of essential devices to ensure the efficient operation of the grid

The multitude of devices that, unbeknownst to our eyes, act in our daily lives to ensure our electrical supply can be overwhelming when considered deeply. This set of elements is commonly referred to as electrical switchgear and constitutes a network of perfectly interconnected systems that are present in the journey of electrical energy from its generation, through its distribution, to its subsequent consumption at endpoints. However, despite its crucial role in making the miraculous mundane, we are not fully aware of what elements are part of this switchgear or how they interact with each other. Today, we aim to address this by explaining this and other aspects. Let’s dive into it.

As we were saying, the switchgear could be defined as the set of devices – with technological developments at different levels – that control, command, measure, protect, transform, and distribute electrical energy safely and efficiently. They ensure, through their specific roles, that our homes, workplaces, industries, critical infrastructures, transportation systems, or power generation plants can function normally. These unfamiliar elements, which can be installed either outdoors or indoors depending on their location and functions, are what ensure the electrification of society, further facilitating the integration of renewable energies in our fight against climate change. Behind every kilovolt powering our lights, operating our appliances, charging our electric vehicles, or preserving our food, lies a technological device making it possible.

A set of medium-voltage switchgears

These systems are spread far and wide across our landscapes: cables traversing our fields to carry energy to cities, substations dotting the outskirts of industries or towns, prefabricated concrete transformer stations above and below our sidewalks, low-voltage panels near our homes… In essence, an entire world of elements that collectively represent one of the greatest technological wonders of our time, enabling the second industrial revolution and shaping our current society.

How are the elements of the switchgear classified?

We can divide electrical switchgear according to the following classifications:

Type of function

  • Switching gear: devices for connection and disconnection (disconnectors, switches, contactors…).
  • Protective gear: systems ensuring the operation of other elements, preventing supply cuts (fuses, circuit breakers…).
  • Measurement gear: equipment calculating electrical consumption (meters).
  • Regulation gear: adapts electricity conditions to consumption requirements (low-voltage panels).
  • Control gear: manual, automatic, or remote manipulation systems (relays).
  • Reactance coils and capacitors.

According to voltage level

  • Low voltage (LV): ≤ 1,000 V AC, ≤ 1,500 V DC.
  • Medium voltage (MV): 1 to 36 kV (can reach 45 kV).
  • High voltage (HV): 45 to 220 kV.
  • Extra High Voltage (EHV): >220 kV.

According to location

  • Indoor installations: elements located within a sheltered place (a building, a prefabricated structure made of concrete and/or metal sheeting…), protected from external environmental factors like water, cold, heat…
  • Outdoor installations: installation occurs outdoors, and the devices are designed to be exposed to climatic factors. Examples include cables, transmission towers, or pole transformers.

According to protection

  • Unprotected or open: devices lacking a protective covering.
  • Protected with metallic enclosures: have a covering to ensure their lifespan.
The switchgear is an essential part of the integration of renewable energy into our society.

Uses of switchgear

  • Domestic installations: lighting systems, power outlets, appliances, security systems, among others.
  • Industrial installations: Used to control machinery, automation systems, power distribution to large equipment, circuit protection, among other industrial applications.
  • Public installations: Employed in public lighting, transportation systems, supplying power to public buildings, among others.
  • Electrical grids: Their functions include supporting the generation, production, storage, distribution, control, or transformation of electrical energy.
A very relevant portion of switchgear elements can be unified into a joint solution, ready to meet the new requirements of the grid, such as Ormazabal’s Digital Transformation Station.

What elements compose electric switchgear?

Electric switchgear comprises an extensive variety of elements such as low-voltage panels, transformers, wiring, energy meters…

Let’s examine some of the most important ones:

  • Wiring: The primary electricity conductor found in underground lines or visible between towers and poles.
  • Electrical transformers: Used to adjust electricity values based on consumption needs.
  • Switchgears or breakers: Serve as line switches, protective devices, and/or meters.
  • Low-voltage boards: Adapt electricity for the specific uses of final consumption points.
  • Transformer stations: Bring together various elements such as those mentioned earlier under a concrete prefabricated or metallic enclosure, offering an integrated solution.
  • Meters: Crucial for measuring the consumption level of end electricity users.
  • Control and protection elements: Serve as the brain of the electrical network, in communion with other elements, allowing automation and remote management of the network.
The STAR project by Iberdrola enabled the installation of 11 million smart meters for their remote management, monitoring, and automation, thanks to the adaptation of over 90,000 transformer stations.

Therefore, the design of the elements themselves and the configuration of the electric switchgear as a whole ensure reliable power supply.

Digitization and automation as guarantees for the future of the grid

In this regard, the present and future of switchgear revolve around ensuring its digitization and automation. Jose María Torres, director of Ormazabal’s Smart Grids division, defines this concept as “a primary objective to achieve the decarbonization goals set by the European Union.” Torres maintains that current geopolitical and exogenous factors “have accelerated the transformation of the electrical industry towards a world with greater integration of renewable generation and more sustainability.” This is an area where “the European Commission and the Spanish government, through the PNIEC, are aligned in seeking a global shift towards sustainability; an objective shared by companies in the electrical sector.”