| 摘要 |
An apparatus for detecting specific conditions in a current transformer during the establishment of a short circuit current and anticipating saturation to prevent the connection of the transformer output to a utilization device. The apparatus include a voltage divider connected to the secondary winding and an integrater connected to integrate a portion of the voltage developed across the divider. The result of the integration is monitored as to direction and magnitude and an output signal is generated which is indicative of both direction and whether or not the magnitude has exceeded a predetermined threshold. This value is used as being representative of the generation of flux in the magnetic circuit. Simultaneously, the sign of the derivative of the current is determined. The signals thus generated are coupled to a circuit which performs the logical decision S = A .B + A . C. A signal resulting from this decision inhibits connection of the transformer to the utilization device. |
