GB1085465A - Arrangement for limiting exess currents - Google Patents

Abstract

1,085,465. Transmission and distribution networks. LICENTIA PATENT VERWALTUNGS G.m.b.H. Jan. 1, 1965 [Jan. 4, 1964; Feb. 28, 1964], No. 53/65. Heading H2H. A circuit for preventing excess current in the connecting link between two inter-connected A.C. power networks I and II includes two reactors, such as a capacitor C and an inductor L, which have reactances of opposite sign and of the same magnitude and which form a series resonant circuit of low impedance under normal conditions; one of the reactors is currentdependent, e.g. the inductor L may be saturable, so that when an excess current flows in the link the resonant circuit is de-tuned, whereby the total impedance increases considerably to limit the current to a predetermined value. The odd harmonics which arise during operation of the circuit may be suppressed by providing tuned circuits l, C 3 , C 2 , C 1 associated as shown with the inductor L. The reactors may be connected to the secondary winding of a transformer having its primary winding in the connecting link (Fig. 4, not shown). A shunt impedance may be connected in parallel with the resonant circuit to provide a path taking part of the current flow (Fig. 7, not shown). In another embodiment (Fig. 6, not shown), the capacitive reactance is made current-dependent by connecting a saturable reactor together with a resistor in parallel with the capacitor C.