GB836284A - Means for operating several cooperating constituent static current converters - Google Patents

Abstract

836,284. Converters. ALLMANNA SVENSKA ELEKTRISKA A.B. Jan. 29, 1958 [Feb. 1, 1957], No. 2936/58. Class 38 (2). In a converting arrangement wherein two converters 1, 2 are associated with transformers 3, 4 which each have first-line windings (23 and 24) and second line windings (18 and 20), the first windings 23, 24 being connected to a first A.C. network 5 and the second windings 18, 20 being connected to a second A.C. network 21 which is a synchronous machine providing reactive power, this connection being made through first compensating reactors 19 such as are disclosed in Specification 682,743 and which are effective in isolating a disturbance in one converter from the other, there are provided means whereby the voltages across the reactors 19 are not short-circuited by the series leakage reactances between the windings 18 and 23, and 20 and 24. As shown, these means comprise compensating reactors 27 which may be earthed. The reactors 19 and 27 may be on a common core. Each converter may be used independently by the provision of switches 25, 26 and by-pass valves 29, 30 (normally blocked). In an alternative arrangement (Fig. 3, not shown) the reactors 27 are replaced by transformers whose secondary windings are shunted across the reactors 19. In a further arrangement (Fig. 4, not shown), the windings 23, 24 are connected in series to earth and supplied through one switch 25 only. In an arrangement (Fig. 5, not shown) wherein a number of pairs of converters such as 1 and 2 are used, each pair of reactors 27 are connected by a further reactor joining their centre tappings. Each pair of these further reactors are similarly joined by yet another reactor and this continues until a stage when only one reactor is required. Fig. 6 shows a plurality of converters 42-49 (one phase only being shown) the first line windings including earthed reactors 82-89 each provided with a secondary winding which are connected in series. As shown, reactors 88, 89 may be transformers, several separate sources of reactive power may be replaced by a single common source.