Processing unit e.g. programmable logic controller, for e.g. power switch of energy distributor, has electric circuit in which spectral portion of fundamental frequency of measurement variable is calucated by Goertzel algorithm

摘要

The processing unit (2) has an electric circuit (1) in which spectral portion of fundamental frequency of a measurement variable is calucated by Goertzel algorithm, where the measurement variable is current and voltage of the electric circuit. The spectral portion is calculated parallel to other spectral portions. Harmonic content of the electric circuit is analyzed by a power switch (3) of an energy distributor and a power monitoring device. The processing unit tests quality of the electric circuit. Independent claims are also included for the following: (1) a method for determining harmonic content of an electric circuit (2) a computer program product comprising a program code for executing a method for determining harmonic content of an electric circuit.