The works include reconstruction of one of the most important high voltage substations in central Tallinn as a turn-key project. Scope consists of design, renovation works of the substation building, delivery and installation of new high voltage equipment, relay protection and telecommunication devices, electrical works and commissioning. To ensure electrical supply in central Tallinn, works will be conducted in two stages. Due to lack of space, it is required to use 110kV insulated busbar for the first time in Estonian electrical system which will ensure safe high power transmission.