6.5.1.2 Results and
Discussion All the buses experienced voltage changes, V, because of wind integration; the weaker
system experienced higher changes in voltage. The buses closest to the PCC experienced the highest
change in voltage levels; the capacity of a grid to absorb wind power is usually determined at the PCC.
When reactive power was introduced into the system there was a reduction in voltage change. 6.5.1.3
Determination of the Grid Type The type of grid can be determined from the simulation results as
follows. The equation, ΔV = Sw/Sk cos (ψ – φ) given in (2.76) shows that a higher the voltage deviation
(V) at the PCC indicates a lower short circuit capacity, Sk, and therefore the lower the ability of a grid
to absorb wind energy. The grid, seen from the PCC, can be modelled as a stiff voltage source in series
with an impedance
Z