Identifying the voltage level

The voltage levels of transmission lines in Finland are 110, 220 and 400 kilovolts (kV). One kilovolt is 1,000 volts (V). The voltage level can be recognised by the length of the insulator string and the number of insulator elements.

Voltage level of a transmission line	Length of insulator string	Number of insulator discs
110 kV	approx. 1 metre	6–8
220 kV	approx. 2 metres	10–12
400 kV	approx. 4 metres	18–21