| 摘要 |
1334403 Protective arrangements ALLMANNA SVENSKA ELEKTRISKA AB 19 April 1971 [16 March 1970] 24025/71 Heading H2K An input circuit for a three-phase overcurrent relay comprises for each phase R, S, T a current transformer TR, TS, TT with a rectifier bridge LR, LS, LT connected to its secondary winding, the rectifier bridges being series-connected on the D.C. side to output terminals 4, 5. An inductance 1 and a series resistor 2 are connected across the output terminals and are so dimensioned that the sum of the voltage arising across the resistor due to the direct current output of the bridges and the voltage arising across the inductance and the resistor due to the alternating voltage component superimposed on the direct current is substantially the same for a single phase fault and a three-phase fault of the same magnitude. A further resistor 3 may be used to facilitate adjustment and high ohmic impedances RR, RS, RT may be connected across the secondary windings. |
