Abstract
Power system faults can cause voltage sags that, if
they are less than voltage sensitivity threshold of
equipment, can lead to interruption of supply and
lead to incurring of financial losses. The impact of
distributed generation (DG) on these financial losses
is investigated in this work. Using the method of
fault positions, a stochastic approach to determine
voltage sag performance, profiles of magnitudes of
remaining voltages at a monitoring point for faults
occurring along lines in the network is developed. It
follows that an expected number of critical voltage
sags at a monitoring point is calculated and the
expected cost of these sags is derived for various
voltage sensitivity threshold limits. An illustrative
study is carried out comparing the expected costs of
voltage sags for a network without DG with a DG
case, for various mixes of customers. It is shown that
in the presence of DG, the expected costs of voltage
sags are lesser for all voltage sensitivity criteria
assumed and for all customer mixes. The study
demonstrates that the impact of incorporating DG
sources results in a reduction in the expected cost of
voltage sags.