GB874306A - Improvements in or relating to electric current supply installations having parallel-connected synchronous generators - Google Patents

Abstract

874,306. Running generators in parallel. SIEMENS-SCHUCKERTWERKE A.G. Jan. 10, 1958 [May 22, 1957], No. 1072/58. Class 38 (4). In a system comprising parallel-connected self-excited synchronous generators of the type wherein the excitation current is derived from the terminal voltage and load current through a transformer and excitation rectifier, the exciters are also parallel connected, those requiring different voltages being connected to separate additional rectifiers giving equal voltages in order to provide a required distribution of load and reactive current. An alternator 1a is excited by a winding fed with the sum of components derived from the terminal voltage and load current through a transformer 3a and a rectifier 2a, the exciting winding being parallel connected to a similar winding on a second alternator 1b. A third alternator 1c requiring a different excitation voltage has an additional rectifier 7 fed from taps on its corresponding transformer 3c so that the voltages on rectifiers 2a, 2b, 7 are equal. Capacitors 5a, 5b, 5c provide self excitation of each alternator. In another arrangement the alternators are each provided with an additional rectifier fed from taps on its corresponding transformer, the excitation and additional rectifiers of like generators being connected in parallel and crossconnected with the excitation and additional rectifiers of generators requiring different voltages.