Figure 1.5 Voltage profile of the 33-bus distribution network before and after placement of DGs for 15^th load hour.

      1.5.2 Optimum Placement of RDGs and Shunt Capacitors to 69-Bus Distribution Network

As mentioned earlier, using mixed discrete SPBO the sizes and locations of biomass DG, solar PV, and shunt capacitors have been optimized. The size of solar PV and the locations of the RDGs and shunt capacitors have been optimized considering 15^th load hour of the day. The optimum locations of biomass DG, solar PV, and shunt capacitors are found to be bus numbers 61, 21, and 17, respectively. Table 1.7 presents the optimum sizes and locations of biomass DG, solar PV, and shunt capacitors obtained using the mixed discrete SPBO algorithm, with an objective to minimize the J for different load hours. Figure 1.6 presents the graphical representation of a comparative study of active power loss before and after placement of RDGs and shunt capacitors to 69-bus distribution networks. From Table 1.7 and Figure 1.6, it may be clearly noticed that, after the placement of RDGs and shunt capacitors to the distribution network, the active power loss reduces significantly for all the load hours of the day considered in this study. At the 15^th load hour, the active power loss reduces from 224.96 kW to 11.2002 kW. Even in the absence of solar power injection, the active power loss reduction after the placement of RDGs and shunt capacitors is found to be quite significant for different load hours. Figure 1.7 shows the reduction VDI, after the placement of RDGs and shunt capacitors for all the load hours of the considered day. From Figure 1.7 and Table 1.7, it may be noticed that the reduction of VDI is quite significant for all the load hours, which implies a significant improvement of voltage profile after the placement of DGs to the distribution network corresponding to each load hours. Figure 1.8 shows the improvement of voltage profile after the placement of DGs to the distribution network for the 15^th hour, using mixed discrete SPBO.

      From the study, it is worth noting that after the placement of biomass DG, solar PV and shunt capacitors to the distribution networks, the active power loss, and VDI reduces quite significantly for both the considered distribution networks and for all the load hours of the considered day. The effective annual installation cost is also found to be less for both the considered distribution networks. It may also be said that the mixed discrete SPBO is quite capable to optimize the sizes and locations of the DGs, in order to achieve the desired objectives.

Table 1.7 Optimum placement of RDGs and shunt capacitors to the 69-bus distribution network.