Further technical development of the mercury arc valve as well as other components in the converter stations and transmission equipment such as transformers, reactors, switchgear, and protection and control equipment resulted in a completely new approach that was implemented by ASEA in the 1954 HVDC link to the island of Gotland 2. This 20 MW 200A 100kV line marked the beginning of the modernera of HVDC and the concept was so successful that has remained basically unchanged since.