Abstract:
Distribution system expansion planning (DSEP) is an important task of electric distribution
companies in order to appropriately supply their customers. The integration of distributed
generator (DG) in distribution network has affected the planning and overloaded problem
additionally, reduction in losses, improving voltage profile and reduction line loading are its
economic and technical benefits. This thesis is mainly investigated Performance Assessment of
Dire-Dawa Distribution Network with DG. Firstly, forecasting peak load for coming ten years by
list square extrapolation techniques. To fulfill the predict peak load demand distribution generator
is integrated to distribution system by sensitivity index method. After ten years dire dawa
substation peak load is become 75.4MW by 5.35% growth rate. After two years substation is
overloaded and to overcome this problem two DG with 12.4MW capacity, for each are integrated
into the distribution system at 15kv main bus. Reliability of distribution system for past three
years was analyzed, from the analyzed expected energy not supplied (EENS) of the system due
to the failures is 8879.83MWh and expected interruption cost (EIC) of the system is 13.3
million$/yr during 2018, the expected energy not supplied (EENS) of the system due to the
failures is 7780.8MWh and expected interruption cost of the system is 11.67 million$/yr during
2019 and the expected energy not supplied (EENS) of the system due to the failures is
8217.6MWh and expected interruption cost of the system is 12.32million$/yr during 2020.
Finally, voltage profiles and power losses before and after DG integration were compared. The
results showed a voltage profile within limit of 0.89 - 1.05 p.u and active power loss reduction of
28.46% as well as reactive power loss reduction of 45.2%. So, this result shown that even if load
demand increases 5.3% each year, then the proposed DG units are able to meet the demand
requirements until ten years (2030 G.C).
