GB985190A - Improvements in automatic control systems - Google Patents

Abstract

985,190. Automatic power control systems. REGULATEURS EUROPA Ltd. Sept. 11,1963 [Sept. 11,1962],No. 34677/62. Heading G3R. In an arrangement in which a load is supplied by two or more "local" alternators A, B augmented by the public electricity supply E, the output of the master alternator A is varied automatically with the load demand so that the load taken from the public supply does not exceed a predetermined value. This value is represented by a preset adjustable load reference H which forms one input to a comparator G whose other input is from a load-measuring circuit F connected to the public supply E,the resultant signal from comparator G being fed to a three-position switch I for the speedsetting motor (not shown) on the governor of the master alternator A. To ensure that alternators A, B maintain their correct proportion of the total demand (less that provided by the public supply), further load measuring circuits J, K are connected respectively to these alternators and to another comparator L whose output signal is fed to a threeposition switch M controlling the governor of alternator B. If provided,a third alternator C is similarly controlled by comparing its output with that of A through circuit elements N, L,O. If the load demand falls to that provided by the public electricity supply, the measuring circuits F, J, K, N, may be used to indicate total demand in a circuit arranged to initiate appropriate switching-off of either the public supply or the local alternator sets,which may be started up again for a rising demand in a similar way. Elements F,J,K,N may comprise conventional static circuits, and switches I,M,O may be either polarised relays or known static circuitry.