UPGRADING THE POWER SUPPLIES OF TEXTOR FOR THREE TESLA OPERATION
The toroidal magnetic system of TEXTOR can tolerate a magnetic field load of up to 2.6 Tesla routinely at full plasma current, and of up to 3 Tesla under certain boundary conditions and for a restricted number of discharges. The original power supply which can generate a toroidal magnetic field of 2 Tesla has been upgraded to operate at a field strength of 3 Tesla, by adding a new, controlled rectifier, with its own independent control, connected in parallel with the first. Studies were undertaken to determine its behaviour where control is lost, such as when a circuit breaker trips or in "freewheel" operation. This paper analyzes this asymmetrical arrangement and discusses the danger of damaging the smaller unit by commutating a large current into it. Moreover, in order to improve the availability of TEXTOR, the new controlled rectifier is redundant to two other units that control the vertical field and the ohmic heating coil currents. For this purpose the two bridges of this 12-pulse system are to be changed from a parallel to a series connection, the freewheeling diodes are disconnected and redeployed to block the large voltage pulses that are induced at plasma initiation, and 3-phase "freewheeling" thyristors are added that serve to reduce reactive power consumption.
Bibliographic Reference: 11TH SYMPOSIUM ON FUSION ENGINEERING, AUSTIN, TEXAS (USA), NOV. 18-22, 1985 VOL. I, 1986, PP. 675-678 - TEXT NOT AVAILABLE
Record Number: 1989125051700 / Last updated on: 1987-11-01
Available languages: en