Electrical current can be transported with different voltages. Theoretically, the same amount of electrical energy can either be transmitted with high voltage and low current or low voltage and high current. However, in practice the ratio between voltage and current is relevant. The energy loss caused by conductor resistance can be reduced by lower current.
Extra-high voltage systems with voltages of 220 kV and 380 kV are used for transport and distribution of electrical energy over great distances. Alternating current voltage of up to 380 kV is generated to reduce energy loss. HVDC power lines could be used in the future. In Germany all highest voltage networks of the energy suppliers to form the German interconnected system. The German transmission has been incorporated into the European extra-high-voltage system which provides electrical power supply between neighbouring countries in Europe.
High voltage systems with voltages of 110 kV transmit electrical current of highest voltage substations to regions of high power consumption, for example factories, metropolitan areas and the rail traffic.
Medium voltage systems with voltages of 10 kV to 50 kV provide further distribution mainly in the rural areas to supply power to the communities and local trades.
Low voltage systems with voltages of 230 Volt and 400 Volt transmit electrical current to private households and factories. Mainly underground cables are used in these networks.
Typical measurement values are available in the database of exposure sources.