Mixed generator-rectifier power for JET (A manufacturers view)

JET needs Peak Power approaching 700MW d.c. probably from a mixture of Flywheel-Generators and a Power System. Generators can be High-Speed type with separate flywheels or Low Speed, vertical shaft, water-wheel type. The Toroidal Field requires a Generator, and diode rectifiers, in series with a diode-thyristor unit supplied from the a.c. System. The Poloidal Field can be supplied from a Generator via Thyristor rectifiers with current reversal by circuit-breakers or anti-parallel thyristors. Low Speed Generators are preferable. They operate below any critical speed, and can be shut down quickly. Main Power Rectifiers are liquid-cooled, similar to those used by industry. The effect of the pulse load on a national electricity supply system is looked at with respect to voltage fluctuations and harmonic current injection. Reactive power compensation is discussed and one type of compensator is described. Power Supply will be chosen for lowest total cost over the life of the experiment. This requires low first cost, high all-day efficiency, and minimum supervision with proven reliability