CURRENT CONVERTER INSTALLATION WITH AT LEAST TWO BRIDGE CIRCUIT, CONTROLLABLE COMPONENT CONVERTERS CONNECTED IN SERIES AT THE DIRECT-CURRENT SIDE

摘要

1,270,280. HVDC converters. LICENTIA PATENT - VERWALTUNGS G.m.b.H. 30 July, 1969 [31 July, 1968], No. 38326/69. Heading H2F. In an HVDC converter installation comprising a plurality of bridge type constituent converters connected in series on their D.C. side, in order to remove an individual converter from service with uninterrupted operation of the remaining converters, the turn ON pulses to the rectifiers in one half of the bridge e.g. rectifiers 31, 33, 35 (Fig. 1) are blocked at times t 1 (Fig. 2c) by a control arrangement (not described) and then only 180 electrical degrees later at time t 2 the (Fig. 2d) turn-ON pulses to the rectifiers 32, 34, 36 in the other half of the bridge are blocked. As shown, Fig. 2b, valve 31 has received a control pulse and is maintained conducting by a smoothing inductance (not shown) on the D.C. output side and valves 32, 36 on the lower half of the bridge receive turn ON pulses. Valve 32 is likewise maintained conducting by the smoothing inductor (not shown). Thus valves 31, 32 conduct simultaneously and act as a shunt valve so that by-pass switch 7 can be closed and the converter 30 can then be withdrawn on both the A.C. and D.C. sides, for testing. Depending upon the moment within the A.C. cycle at which blocking is effected, either the valves 31, 32 or 33, 34, or 35, 36 act as shunt valve. Preferably it is arranged for blocking to be applied at a predetermined instant in a cycle so that the same two valves always act as shunt valve and as such are selected to have a higher rating than the others.