Anordnung zum Dämpfen von Ferroresonanzschwingungen und asynchronen Untertonschwingungen eines Reihenkondensators

1,029,625. Protective arrangements for series capacitor circuits. ALLMANNA SVENSKA ELEKTRISKA A.B. Feb. 25, 1963 [Feb. 26, 1962], No. 7407/63. Heading H2H. To suppress ferro-magnetic and asynchronous sub-harmonic oscillations which may arise in a phase 12 of a power line due to the presence of a series capacitor 11, an inductive member 13, a damping resistor 14 and a transformer having primary and secondary windings 15, 16 are connected as shown in Fig. la, so that, by suitable choice of the turns ratio of the transformer and the inductance of member 13 in relation to the capacitor 11, the voltage across the resistor 14 is virtually zero at normal operating frequency but becomes considerable at substantial deviations from this frequency. The windings 15, 16 may be connected to produce an auto-transformer effect, Fig. lb (not shown). Fig. 2a shows another arrangement which may be modified by connecting the resistor 24 across the secondary winding 26 or the primary winding 25, Figs. 2b and 2c (not shown), or by providing the transformer with a third winding across which the resistor is connected, Fig. 3 (not shown). Where the circuit configuration allows, the damping resistor may be provided by forming the winding with which it is associated from wire of relatively high resistivity. In cases where the inductive member is parallelconnected to the secondary winding, these two members may be built together so that a combined transformer and inductive member is obtained, Figs. 4a, 4b and 4c (not shown).