Verfahren zur Überwachung eines Schutzgerätes

摘要

The invention concerns a method for operating a protective gear devices (1), in particular a remote protective gear for a power grid (Ln), whereby a voltage signal (Un) is derived from the power-supply voltage (Uln) and an intensity signal (In) is derived from the line current (ILn). In order to ensure a reliable detection of an error occurring in the measurement circuit (2) of the protective gear (1), a logic link is set up between a voltage drop (U < Us) and a sudden variation in intensity (dI/dt). A monitoring unit (9) provided therefor, combines a first signal for the voltage drop (Un < Us), derived from the voltage signal (Un), and a second identification signal (E2) for the sudden variation in intensity (dI/dt), derived from the current signal (In). The monitoring function is adapted both to uniphase networks and polyphase networks and enables to distinguish with certainty an error occurring in the network from a breakdown of the measurement circuit (2).