medium voltage network (smart grid) (MVN)
Electricity networks are classified according to their voltage values. Low-voltage networks have the lowest voltages. These range up to voltages of 1 kV( AC) and 1.5 kV( DC). Medium voltage networks have the next highest voltage level.
Medium voltage networks are power networks for voltages of 10 kV, 20 kV and 30 kV. It should be noted, however, that the limit values for the voltages are fluid. Thus, values between 1 kV and 52 kV may well be specified in other documentation. Medium-voltage networks are three-phase current with a frequency of 50 Hz. They are mainly used in localities and urban areas. Their extension may well be 100 km in rural areas. In rural areas, transmission is via overhead lines, in urban areas via underground cables. Medium-voltage networks are usually constructed in a star configuration and connected to low-voltage networks via transformers.
The next higher voltage level above the medium-voltage networks are the high-voltage networks with 60 kV up to 150 kV, above which are the extra-high voltage networks with 220 kV and 380 kV. Higher voltages of 1.15 MV were previously realized with high-voltage direct-current transmissions.