A substation platform (10) for use in offshore power transmission comprises a primary floor (12) including at least one opening, at least one transformer assembly (14) including one or more transformers (24) for connection in use to one or more electrical networks, the or each transformer assembly (14) being releasably connected to the primary floor (12), and at least one strand jack (16) including one or more cables (28), the or each cable (28) being operable to releasably connect to a respective transformer assembly (14) and the or each strand jack (16) being operable to lower or lift the respective transformer (24) through the respective opening of the primary floor (12).
