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

The low voltage grid 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 grids at different voltages, we find that the low voltage grid is the closest to the usual consumption points we deal with on a daily basis. However, something as everyday as this is sometimes a completely unknown phenomenon. That’s why today we want to explain how the LV grid works and what elements make it different from its siblings. Are you with us?

To understand what the low voltage (LV) grid is, we must first understand what we mean by electrical voltage and what types exist. Electrical voltage is a measure (a physical magnitude technically speaking) that allows us to calculate the difference in electrical potential between two points in a grid. This would be something like the flow – speaking in terms of rivers – that a wiring can support along its line; therefore, the more electrical potential (greater amount or electrical charge), the higher the voltage that the grid is capable of transporting and/or supporting in a controlled and efficient manner.

So, in the world of electrical engineering, three main types of voltage are distinguished: high voltage, medium voltage, and LV. We 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. Normally, the voltage is higher in the initial phases of energy transportation, where greater electrical potential is needed to increase the “flow” and try to reduce losses.

Subsequently, as we approach the consumption points, the voltage must be reduced for safety, to minimize the risk of accidents from handling, and to align with the ranges of use of the circuits and devices with which we interact in our daily lives. This is where our protagonist today comes into play.

The low voltage grid and its characteristics

In this way, we can define the LV as one that operates within voltage ranges of up to 1 kV in alternating current. These characteristics are present every time we use an appliance – usually they operate at voltages between 220 and 230 volts in alternating current – or turn on a switch in our homes. This is why it is the most common type of voltage for all of us, as it facilitates our daily lives.

So, we find different everyday uses of LV. Let’s see some examples:

• Residential use
  • Lighting
  • 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
  • Telecommunication networks
• Physical security
  • Perimeter surveillance systems

Which elements of the electrical switchgear work in LV?

For all this to work, there are a series of agents that work together at different points in the LV grid. Let’s take a look at the main ones:

• Transformer station: These stations act as large controllers and energy distributors in the complex grid. Located at the exits of substations to our electrical grids, the CTs – its abbreviation – distribute and deliver electrical energy to consumption zones thanks to sophisticated protection and automation systems in the grid. For this, they bring together some of the key elements in the LV grid, such as the following:
• Low voltage board: This is the main protagonist of the LV. Its function is to distribute and protect energy to our homes. Having transformed – reduced – the voltage value in the transformer, the current value increases, and this element allows distributing and protecting said current value in a certain number of outlets that will go to our homes.
• Electrical transformer: It is another prominent agent of the CT and is an electrical element that allows increasing or decreasing the voltage of an electrical circuit for its subsequent distribution. In this way, it allows the voltage to be subsequently reduced in the low voltage panel.
• Differential/fuse panel: When energy is distributed, it reaches the differential panel located outside our houses, which serves as protection for our grid; ensuring that in case of a possible alteration, all connected elements are protected by fuses, thus preventing damage.