What is the secondary distribution grid and what elements comprise it?

Perhaps you’ve heard of the secondary distribution in the power grid, but do you know what it is and what elements are part of it?

Understanding how the world around us works makes us appreciate the complexity of many everyday things whose operation we take for granted. One of the main protagonists of our daily lives is electrical energy, which makes our lives much easier and whose operation is extremely interesting and necessary. Electrical energy travels a long way, from generation to reaching consumption points, through the distribution grid until it can be consumed, for which its transformation and distribution at each of the key nodes is indispensable to ensure supply and safety.

Thus, we can distinguish between two main phases when we talk about distribution: the primary distribution grid and the secondary distribution grid. Today we will focus on explaining what it is and what elements are part of the latter, which is the closest to consumption points. Let’s dive into it.

When we talk about the term electrical distribution grid, we refer to the existing infrastructure that enables energy to reach customers and end consumers from the large high-voltage transmission lines (between 220 kV and 400 kV) that we all recognize. As we mentioned, the treatment of electrical energy is tremendously complex in its different phases (generation, transmission, distribution, and consumption) and requires many elements of different complexities such as cables, electrical equipment, poles, towers, substations…

The location of each of these elements in the grid is not random but responds to technical requirements that guarantee stable and safe lighting in our homes, as well as ensuring that each kilowatt of renewable energy generated is used as efficiently as possible. When distinguishing the main phases of the distribution grid, we can divide it into two main groups:

• Primary distribution grid: This is the stage of electricity distribution where energy reaches substations to be transformed and distributed at medium voltage to the next phase of the grid for direct consumption by electro-intensive consumers such as industry.
• Secondary distribution grid: This is the stage of the electricity distribution system where the voltage values of the energy are adapted for safe and efficient delivery to consumption points such as our homes, offices, hospitals… It is based on the work of medium-voltage transformation centers, which adapt the energy voltage for its transition to low voltage and subsequent consumption by the end user.

The secondary distribution grid and its main elements:

If we focus on the secondary distribution grid, we can distinguish several elements that perform the main functions for its proper operation. Let’s see what they are:

• Feeder cables: These are the main transport arteries for electrical energy within the secondary distribution grid. Despite appearing to be simple cables, they are designed to withstand significant electrical currents, reducing losses and prioritizing safety. They are also protected by devices against overloads and short circuits, as well as connected with grid measurement and monitoring devices for proper management and monitoring.

• Transformation centers: These centers act as large controllers and distributors of energy in the vast grid. Located at the exits of substations to our electrical grids, the CTs distribute and allocate electrical energy to consumption zones thanks to sophisticated grid protection and automation systems. For this, they aggregate some of the key elements in the secondary distribution grid, such as the following:
  • Electrical transformer: This is the main component of the CT and is an electrical device that increases or decreases the voltage of an electrical circuit for its subsequent distribution.
  • Secondary distribution switchgear: The switchgear, which plays a key role in the complexity and technological development of the center, is used for different functions depending on its type, but it would be a major switch that cuts off or allows electrical energy to flow. For this, technological development is fundamental, achieving a solution that allows operating the grid at medium voltage values with total safety for the operator and the grid under the most adverse conditions.
  • Protection, control, and automation units: These elements are one of the main revolutions of the medium-voltage grid in recent years. Their functions, ranging from remote control of medium-voltage transformers, through reporting and diagnostics to automation, have allowed the grid to be equipped with intelligence; making them a key ally in the smartization of the grid.
  • Low-voltage board: Although technically this is an element that operates at low voltage, it is responsible for dividing the current to be transported, safely, directly to consumption points. In this way, the LV panel distributes and protects energy to our homes.

Ormazabal, expert in electrical solutions for secondary:

At Ormazabal, we work to transform the electrical grid into a future infrastructure: more reliable, resilient, and sustainable. Thus, we have more than 55 years of experience in the design and manufacture of electrical solutions for secondary distribution aimed at digitizing the electrical grid to integrate more renewable energy generation, enable more sustainable mobility, and ensure electricity supply to buildings and infrastructures with critical energy needs.

Within our route to zero, we have launched our innovative ranges of products free of fluorinated gases, based on insulation in natural industrial air, for the public distribution market up to 24 kV cgm.zero24. The most complete alternative solution to SF6 insulation on the market, guaranteeing zero changes, zero uncertainties, and a more sustainable electrical grid.

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