What is the low-voltage grid and how does it work?

The low voltage network is part of one of the three ranges of electrical voltage and has its own technical characteristics

If we understand the electrical grid as a large set of interconnected networks at different voltages, we will find that the low-voltage network is the closest to the usual consumption points that we deal with on a daily basis. However, something as everyday as this is sometimes a completely unknown phenomenon. Therefore, today we want to explain how the low-voltage network works and what elements make it different from its sister networks. Will you join us?

To understand what the low-voltage network is, we must first understand what we mean by electrical voltage and what types exist. Electrical voltage is a measurement (a physical magnitude, technically speaking) that allows us to calculate the difference in electrical potential between two points in a network. This would be something like the flow – speaking in river terms – that a cable can support through its line; then the greater the electrical potential (greater quantity or electrical charge), the greater the voltage that the network is capable of transporting and/or supporting in a controlled and efficient manner.

Thus, in the world of electrical engineering, three main types of voltage are distinguished: high voltage, medium voltage, and low voltage. We will differentiate them according to the amount of electricity they are capable of displacing and how close or far each of them is from the consumption points. Typically, voltage is higher in the early stages of energy transport, where greater electrical potential is needed to increase the “flow” and try to reduce losses.

Later, as we approach the consumption points, the voltage must be reduced for safety, to minimize the risk of accidents due to handling, and to get closer to the usage ranges of the circuits and devices with which we interact in our daily lives. This is where our protagonist of today appears.

The low voltage network and its characteristics

In this way, we can define a low-voltage network as one that operates in reception ranges of 1 kV, maximum, in alternating current. These characteristics are found every time we use an appliance – normally these work at voltages between 220 and 230 volts in alternating current – or flip a switch in our homes. This is why it is the most common type of voltage for all of us, since it is the one that makes our daily lives easier.

Thus, we find different everyday uses for low voltage. Let’s look at some of these examples:

• Residential use

  • Lighting
  • Household appliances and leisure
  • Heating and ventilation

• Commercial use

  • Heating and ventilation
  • Lighting
  • Equipment

• Industrial use

  • Machinery and manufacturing processes
  • Control points
  • Communications
  • Computer equipment
  • Security

• Public lighting

  • Road and street lighting
  • Exterior lighting of buildings and common areas

• Telecommunications

  • Telephony and communication equipment
  • Telecommunications networks

• Physical security

  • Perimeter surveillance systems

What elements of electrical switchgear work on low?

For all this to work, there are a series of agents that work in a coordinated manner at different points in the low-voltage network. Let’s take a look at the main ones:

• Transformation center: These centers would act as large controllers and energy distributors in the great tangle that is the network. Located at the exits of the substations towards our electrical networks, the CTs (their abbreviation) distribute and allocate electrical energy to consumption areas thanks to sophisticated network protection and automation systems. To do this, they bring together some of the key elements in the low-voltage network, such as the following:
• Low-voltage panel: This is the main protagonist of the low-voltage network. Its function is to distribute and protect energy to our homes. By having transformed – reduced – the voltage value in the transformer, the current value increases and this element allows to distribute and protect said current value in a certain number of outputs that will stop at our homes.
• Electrical transformer: It is another of the outstanding agents of the CT and it is an electrical element that allows to increase or decrease the voltage of an electrical circuit for its subsequent distribution. In this way, it allows the voltage to be subsequently reduced in the low panel.
• Differential/fuse panel: When the energy is distributed, it reaches the differential panel located outside our homes and which serves as protection for our network; guaranteeing that in the event of a possible alteration all the connected elements are protected by the fuses, thus preventing them from deteriorating.