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Electrical substation

Découvrez le secteur des postes électriques HT/BT


In France, the transformation and transport of energy is ensured by the RTE company, whose mission is to provide everyone with an economical, clean and safe power supply.

MALTEP is one of the few companies in France to be approved by RTE. And therefore to be able to supply the grounding material of electrical substations.

Transformer substations

Initial power up

A first transformer station is placed directly at the exit of the main power plants to raise the voltage to 400kV. This makes it possible to transport electricity over long distances with numerous interconnections. 

During transportation

Several other transformer stations are distributed along the transmission network, they allow to reduce and redistribute the current to the consumers and to supply the source stations on the distribution network.
Thus, the electrical voltage differs between the input and output of the substation. If we take the example of a 225kV/90kV substation, we will have 225kV at the input and 90kV at the output.

These installations are composed of 3 types of devices:

  • Transformers to reduce voltage
  • Circuit breakers to cut power instantly in case of emergency
  • Disconnectors to switch, establish or interrupt the electrical circuit

Sources: EDF.

The distribution network


This network allows the transport of energy at the local level, from the centers to the consumers (companies, cities, supermarkets, individuals etc...).

In addition to the main power plants, local sources of electricity (wind turbines, micro power-plants, photovoltaic parks...)inject electricity into the grid. If needed, this electricity can be transformed from HV (63 kV - 90kV) to medium (20 kV) or low voltage (230V - 400V).

Medium voltage (MV) and low voltage (LV)

The MV network is mainly located in rural areas, and despite the progressive development of underground lines, it is still mainly composed of overhead lines. It supplies more than 760,000 distribution substations and is equipped with automatic systems to facilitate operation and restoration in case of failure.

At the exit of the transformer stations, these lines run on poles, facades or underground. This network is protected by fuses at the transformer outlet and a circuit breaker on the user's side.

Sources: EDF.