GB867056A - Automatic control device for synchronous generators - Google Patents

Abstract

867,056. Automatic voltage control systems. ALLMANNA SVENSKA ELEKTRISKA A.B. April 29, 1959 [May 9, 1958], No. 14593/59. Class 38 (4). In an automatic voltage control system for a synchronous generator 1 connected to a supply network RST, a field 2 of the generator is energized by an exciter 3 having a series field 4 and an opposing regulating field 5 fed through a transductor 7 from a secondary of a transformer 8 connected to the network. The impedance of the transductor 7 is varied by opposing control windings 9, 10, energized via a saturable reactor 13 and a reactor 15 respectively, from a tapping on the primary of the transformer 8. With an increase in the output voltage of the generator above a desired value the current through the winding 9 becomes greater than that through the winding 10 so that the impedance of the transductor 7 is reduced and the current through the opposing field 5 increased to reduce the excitation voltage of the generator 1 and so tend to maintain the output voltage constant. A third control winding 11 on the transductor 7 is fed through a transductor 17 from a tapping on the secondary of the transformer 8. The transductor 17 has a control winding 19 energized from the secondary of the transformer 8 and a control winding 18 energized via a resistor 21 by the voltage across the generator field 2 so that a current passes through the control winding 11 of the transductor 7 tending to limit the reduction in the excitation voltage with a large increase in network voltage.