The transmission network uses three-phase high-voltage transmission (DHÜ) and is usually 230/400KV (maximum voltage level). It distributes the energy generated by power plants across the country, via coupling lines to the international network and via transformer stations to the distribution network. These networks are monitored and controlled by the TSOs (Transmission System Operator).
The distribution network is the high voltage level (60 - 110 KV). It is usually 110 KV. This roughly distributes the electrical energy to metropolitan areas, to large industrial companies and via transformers into the medium-voltage network, for example. Here the responsibility for controlling and monitoring lies with the DSOs (Distribution System Operator).
In the medium-voltage network (1 - 35 KV), the electrical energy is distributed regionally, to hospitals and substations, for example. This is done by the regional electricity providers.
The low voltage level (up to 1 KV) distributes the energy to private households, small industrial companies and administrations. Here the voltage is usually 230 or 400 V.