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 lineLength of insulator string​Number of insulator discs

110 kV

approx. 1 metre​


220 kV​

​approx. 2 metres


400 kV

approx. 4 metres