Computation of periodic steady state with reduced frequency order

This paper presents a heuristic method for determining the number of frequencies to be included in a harmonic/interharmonic network solution. It is assumed here that the network includes nonlinear reactors and electronic devices. On one hand, the linear part of the network is represented by its Thévenin equivalent. On the other hand, voltages of different frequencies are used to calculate the current drawn by nonlinear loads. The resultant nonlinear current is then coupled, for each considered voltage, to the Thévenin network´s equivalent. This permits a scenario to determine the most contributing frequencies at the interface which will propagate into the linear part of the network. The reasoning that originates the proposed method is that nonlinear loads (and electronic devices) are the main frequency conversion devices in electrical networks. To validate this reasoning, an extension of the harmonic domain is used and applied to an example.