ABSTRACT
Optimal siting and sizing of Distribution Flexible AC Transmission Systems (D-FACTS) devices in power distribution networks maximizes loadability, compensates reactive power, minimizes power loss and enhances voltage profile. The search for optimal size and locations of these devices in radial distribution networks is challenging and requires robust scheduling. This dissertation presents the application of improved bacterial foraging algorithm (IBFA) to the optimal siting and sizing of Distribution Static Compensator (D-STATCOM) in radial distribution networks for power loss minimization and voltage profile enhancement. Radial distribution network power flow model and algorithm was developed based on the Bus Injected to Branch Current matrix (BIBC) technique. The IBFA was modelled with three adaptive run-length units (linear, quadratic and exponential) and the cell-to-cell signalling mechanism was eliminated. A multi-objective function comprising of total active power loss and network bus voltage deviation was formulated for use in the IBFA. The effectiveness and applicability of the approach was demonstrated on standard IEEE 33-bus radial distribution network and the 50-bus Canteen Feeder in Zaria distribution network for steady-state constant load model. The results obtained are compared with those of the conventional BFA; and with Analytical and Bat Algorithm (BA) approaches reported in literature. For the standard IEEE 33-bus test network, the optimal location and size of D-STATCOM were determined respectively as bus 30 and 2577 kVar by the BFA method, while the IBFA approach obtained the optimal site and size of the D-STATCOM in the network to be bus 26 and 3351 kVar respectively. The BFA approach produced a 5.87 % reduction in overall network power losses and an 82.88 % improvement in voltage profile when compared with the base-case scenario. Similarly, the IBFA approach resulted in 5.83 % drop in total power losses of the network and 87.96 % improvement of the voltage profile. An average computational time of 7.2 seconds and 4.9 seconds were obtained for the BFA and IBFA approaches respectively. The results obtained using the IBFA approach showed a 28.5 % and 1.1 % reduction in active power loss and size of D-STATCOM respectively when compared with those of analytical approach. Also, when compared with the BA results, the IBFA approach showed a 50 % improvement in the overall network voltage profile. For the 50-bus Canteen Feeder, bus 41 and 227.8 kVar were found as the optimal site and size of D-STATCOM using BFA method, while for IBFA approach, the optimal site and size of the D-STATCOM in the network were determined as bus 22 and 138 kVar respectively. The overall network power loss was reduced by 22.8 % and the voltage profile improved by 6.10 % using the BFA approach while for the IBFA approach, a 26.53 % reduction in total power loss and a 6.21 % improvement in voltage profile were achieved as compared with the base-case results