Extra-high voltage in the transmission system (level 1)
The transmission grid absorbs the electricity produced by the big power plants or in neighbouring countries. The electricity is transported at a voltage of 380 kV or 220 kV to the vicinity of the consumer. Here it is fed into the lower grid levels, the distribution grids. The Swiss transmission grid is the property of Swissgrid.
High voltage in the supra-regional distribution system (level 3)
In the high voltage level (> 36 kV - 150 kV) electricity is distributed for supra-regional supply to cantonal, regional and municipal distribution grid operators and to major industrial plants.
Medium voltage in the regional distribution system (level 5)
Medium voltage (1 kV - 36 kV) is used for the regional distribution of electricity. Local distribution grids supply individual suburbs or villages and small and medium-sized industrial enterprises.
Low voltage in the local distribution system (level 7)
The electricity arrives as low voltage (< 1 kV) in homes and agricultural and commercial businesses.
The substation connects two voltage levels. The core of a substation is the transformer, which converts the voltage from one voltage level to another: from extra-high voltage to high voltage and from high voltage to medium voltage.
Medium voltage is converted to the low voltages of 400 V required in homes and businesses in the transformer station.