Abstract:
This thesis aimed to investigate the impact of the grid-connected solar roof-top system on
low voltage distribution system for the hospitals with different load profile, buses and locations. The
DIgSILENT PowerFactory program was selected to simulate and analyze power flow, voltage profile,
energy losses and power factor that affected low voltage distribution system for existing PV
installation or the future project.
In order to analyze the impact of the grid-connected solar roof-top system for the hospital
load in the PEAs distribution network, this thesis was designed to install the grid-connected solar
roof-top system capacity as 5%, 10%, 15%, 20% and 27% of 1500 kVA 22/0.4 kV transformer. The
study considered the different load profiles, buses and locations. It showed that the installation 15%
of capacity on every bus yields the voltage profile at the end of bus (350 meter), which was raised
from 0.939 to 0.956 per unit. The results of the 7 installation patterns showed that the transformer
loading of the system had decreased from 79.91% to 75.56%, 71.32%, 67.36%, 67.11%, 63.07% and
57.85% respectively, but the effect of power factor had decreased from 0.88 to 0.86, 0.85, 0.83, 0.83,
0.80 and 0.76 respectively. The Inverters power factor setting on the solar roof-top system from 1.0
to 0.9 affected the power factor of grid system, which increased from 0.83 to 0.88.
The analysis results showed that the optimized installation of the solar rooftop on every
bus at 15% of transformer improved the voltage level at the far-end bus and it also reduced power
losses of the system. The optimized inverters power factor setting improved the power factor to meet
the requirements of the Electricity Authority. The improved power quality resulted in direct and
indirect energy saving.