Device for detecting the open or closed state of a switch and associated transformer protection relay monitoring device

摘要

The device has a current clamping circuit (2) and a voltage clamping circuit (3) arranged in series. An input of the current clamping circuit is connected on a terminal of a switch, where another terminal of the switch is connected to a mass of the device. A comparator (4) comprises an input unit that is connected to an output unit of the voltage clamping circuit. A load regulating circuit (1) is arranged between an output of a low-pass filter (5) and the input unit of the current clamping circuit.