GB785664A - Improvements in or relating to means for operating self-regulating synchronous generators in parallel - Google Patents

Abstract

785,664. Running generators in parallel. SIEMENS - SCHUCKERTWERKE AKT. - GES. Oct. 28,1955,No. 30929/55. Class 38 (4). In order to maintain a desired distribution of wattless current between two or more parallel-operating alternators each having its excitation current obtained, in part, from a current transformer in its output circuit, an equalizing connection is made between the excitation circuits of the several machines at points nominally at the same potential. In the arrangement shown in Fig. 1, parallel-working alternators 1, 100, have individual transformers 4, 400 feeding the D.C. excitation circuits 10, 1000 over rectifiers 3, 300, respectively. The two excitation circuits are connected in parallel by auxiliary contacts 11 of the main paralleling switch 9 and the division of the wattless load on the machines is preset by variable resistors 12, 120 in the excitation circuits. Each transformer has two primary windings, one voltagefed and the other current-fed. In another arrangement, Fig. 2, the D.C. excitation circuits of the two machines are isolated from one another, but equalizing connections 27 are provided between chokes 24a, 24b through which the voltage-fed windings of the two transformers are supplied.