The load current waveform is almost
square in nature, which confirms non-linear load. The VSC current
consists of harmonics current, demanded by load and real power
component, required to feed all incoming power at the DC link
from the PV array. The harmonics spectra of grid, load and VSC
currents are shown in Figs. 6d–f. The load current THD (Fig. 6e)
is of the order of 29% whereas, grid current THD (Fig. 6d) is
below 5% (under IEEE-519 standard). The VSC current THD
(Fig. 6f ) has found about 13% as VSC current consists of
harmonics supplied to the load as well as fundamental active
power component of the current. The –ve sign of power in grid
power (Fig. 6g) shows that the power is being fed into the grid
and DPF of order of −1 confirms the UPF operation with respect
to the grid. The grid power, load power and PV array power are
shown in Figs. 6h − i, respectively.