This factsheet describes overhead high voltage alternate current (HVAC) lines as a part of the high voltage network. These networks transmit large blocks of electricity over long distances. Long-distance transmission is possible due to the high voltage at which HVAC lines operate, usually ranging from 110KV to 400kV. Electricity in high voltage networks goes from power plants to substations close to end-consumers . Power transformers step-up/down voltages between different areas of the transmission network, producers and distribution networks.
HVAC overhead lines typically transport electricity in the transmission network. Only in Europe, there are over 474 thousand kilometres of HVAC lines . Underground cables also carry electricity at high voltages. Nevertheless, the initial cost of the underground transmission system is higher compared to the overhead lines since it requires digging and trenching. HVAC lines also interconnect different areas or countries, increasing the security of supply and improving the reliability of the electricity system. Europe counts with more than 390 cross-frontier lines .