 In contrast to most other HVDC plants, its converters do not allow bidirectional energy to transfer, but only from Russia to the power grid of Finland.Each pole consists of a single Twelve-pulse bridge at each end and was built using thyristors from the outset.The first three poles were originally built using small (60mm) diameter thyristors with three in parallel at each level, but these were later replaced by larger 80mm thyristors which did not require parallel connection.