  An increasing number of renewable energy-based distribution generation (DG)
units are being deployed in electric distribution systems. Therefore, it is of
paramount importance to optimize the installation locations as well as the
power supply of these DGs. The placement of DGs in the grid can decrease the
total distance that power is transmitted and thus reduce power losses.
Additionally, the reactive power supply from the DGs can further reduce power
losses in the distribution grid and improve power transmission efficiency. This
paper presents a two-stage optimization strategy to minimize power losses. In
the first stage, the DG locations and active power supply that minimize the
power losses are determined. The second optimization stage identifies the
optimal reactive power output of the DGs according to different load demands.
The proposed approach is tested on the IEEE 15-bus and the IEEE 33-bus systems
using DIgSILENT PowerFactory. The results show that the optimized power losses
can be reduced from 58.77 kW to 3.6 kW in the 15-bus system, and from 179.46 kW
to around 5 kW in the 33-bus system. Moreover, with the proposed optimization
strategy, voltage profiles can be maintained at nominal values enabling the
distribution grid to support higher load demand.
