Patent ID: 9467070
Filing Date: 2016-10-11
CPC Classification: H02J,H02M,Y02E

Claim Text:
1. A method for monitoring a decentralized power generation plant for feeding into a three-phase grid comprising an inverter, which generates alternating currents which are phase-shifted with respect to one another from an input-side DC voltage, said alternating currents being fed into the grid, wherein the method comprises: a) generating a setpoint power value for each phase of an AC mains voltage, with the result that each generated alternating current is matched to an amplitude, frequency and phase angle of a respective phase of the AC mains voltage; b) changing the setpoint power value for a certain phase of the AC mains voltage by a predetermined first magnitude in a predetermined time period; c) changing, in the reverse direction, the setpoint power value for at least one of the other phases of the AC mains voltage by a predetermined second and/or third magnitude in the same predetermined time period, with the result that the sum of the second magnitude and the third magnitude is equal to the first magnitude; d) generating the alternating currents by means of the inverter on the basis of the changed setpoint power values; e) measuring the amplitude of at least the one certain phase of the AC mains voltage in the predetermined time period; and f) ascertaining if the measured amplitude of at least the one certain phase of the AC mains voltage changes by more than a maximum permissible quantity.