THYRISTOR RECTIFIER HAVING A DEVICE FOR SELF-IGNITION OR RECOVERY PROTECTION

摘要

A thyristor rectifier for high voltage includes a number of series-connected thyristors with a control device for each thyristor and a control circuit for the whole rectifier connected to the control devices. There is a control pulse emitter in each control device which emits an indicating pulse when the voltage over the corresponding thyristor in the conducting direction amounts to a certain value. A protection device is provided which emits a signal for the whole rectifier through a control pulse transmitter if a voltage grows in the conducting direction of the rectifier at a time when only an insufficient number of thyristors have regained their blocking ability. This protection device includes a memory circuit and a counter to register the indicating pulses from the emitters of the control devices and an output circuit connected between the counter and the control pulse transmitter which emits a signal for ignition of the whole thyristor in dependence on a predetermined number of indicating pulses.