Monitoring system for high-voltage switches

A method and an apparatus are disclosed for measuring contact erosion in an electrical switching device by a dynamic resistance measurement (DRM). To determine an overlap time and a contact erosion in an exemplary switching device, a change in current across the switching device can be measured indirectly by a measurement current being passed across the switching device and a parallel conductor, the change in current in the parallel conductor being measured. Exemplary embodiments relate, to the following: detection of a differential current measurement signal in the parallel conductor with the aid of a Rogowski coil; and selection of a parallel conductor resistance on an order of the switch resistance.