Method and device for preventing the occurrence of a possible fire under interference in electrical networks and electrical installations

摘要

Method for preventing the occurrence of a fire under interference in electrical networks (IN) or electrical installations (EI) with: - a measurement of the current (6) in a controlled area, - generating a signal ( 15) of the second harmonic and / or harmonic superior from the spectrum of the signal of the measured current, - a determination of the magnitude of current sparks, wherein for determining the current chip: - the magnitude of pulse width (31) of the training phase and / or extinguishing a cycle "Appearance - extinction of the spark" is measured and - in the training phase of the cycle number of the pulses is measured ( 32), whose amplitudes exceed a predetermined value, characterized in that measurements are made - of the short circuit current (26) and / or - of the overload current (25) and / or - of the discharge current and / or - voltage mains, in which - measured the short circuit current and / or the overload current through the separation of a signal of the first harmonic (23) from the measured current in a controlled area, - measuring (26) the discharge current is performed and / or stress (27) of the grid by: - ​​connecting a sensor bias current and / or - the voltage supply from the mains or power to corresponding protective device installation, and wherein - there is provided an amplification (16) and rectification (17) of the signal generated from the second harmonic and / or a harmonic above, in which the amplified and rectified signal is used for determining the magnitude stream of sparks.