repair and maintenance services of transformers./ work agreement tap changer revision./ 50hertz transmission gmbh currently operates its transmission network with around 80 substations and switchgear at the voltage levels of 110 kv, 150 kv, 220 kv and 380 kv. the scope of services of the tender covers the cyclic revision / maintenance of the on-load tap changer used at 50hertz transmission gmbh. furthermore, interference suppression on the on-load tap-changers and their drive system are covered by the work agreement to be concluded. the on-load tap-changer revision is d on the maintenance instructions of the tap-changer manufacturer. the internal technical specifications of 50hertz transmission gmbh once again refer to focal points or extend the manufacturer's regulations. most of the approximately 300 on-load tap-changers installed at 50hertz come from transformer factory oberschoeneweide (tro) or maschinenfabrik reinhausen gmbh (mr).