Arrangement for the testing of high voltage direct current switches

In a circuit for the synthetic testing of a high voltage direct current switch, which arrangement includes a first direct voltage source having a high current and low voltage output, a first auxiliary switch and a first inductance both connected in series with the source, with the series arrangement of the source, first auxiliary switch and inductance being arranged for connection in series with the switch to be tested, an auxiliary voltage source having a low current and high voltage output arranged to be connected to the switch for stressing the switch to be tested to its voltage breakdown level, the improvement comprising:

• a second inductance connected to said auxiliary voltage source and arranged to be connected in series between said auxiliary source and the switch to be tested;
• a second auxiliary switch connected in series with said auxiliary voltage source and arranged for operatively connecting said auxiliary voltage source across the switch to be tested;
• and control means connected to said second auxiliary switch and arranged for connection to the switch to be tested for closing said second auxiliary switch in order to connect said auxiliary voltage source across the switch to be tested at a time after the opening of such switch and before the current through such switch, supplied by the first voltage source, drops to zero.