Future AC and DC power systems at Culham

Culham ac and dc power supplies are being re-arranged and improved to meet the future experimental requirements of the Laboratory. At present all Culham supplies come from a 132/11kV feeder having a capacity which is insufficient for the future. A new 33kV feeder has been installed taking power on a shared basis from one of the JET 33kV busbars. This has necessitated the building of a 33kV sub-station with facilities for feeding future experimental loads. The new supplies include a 176kV, 100 amp dc supply from four transformer rectifier units. These will be configured via a dc switchyard, using commercially available switchgear, so that the future experimental requirements of ECRH and Neutral Injection can be met. A low voltage dc supply is also planned. This will consist of 2 x 46kA units with thyristor control which can be used independently or in series or parallel. The aim is to have a flexible power source capable of energising future Tokamak toroidal field systems. Flexibility and safety have been essential considerations in the design and layout of these supplies and the paper describes how these have been achieved. It may be necessary in future to consider the loading on the existing 132kV grid supply and this is also discussed