Optimal Placement and Sizing of Distributed Generation (DG) Units in Electrical Power Distribution Networks
Authors: Moses Irekefe A. , Kiprono Letting L. , Talai Stephen M. 
Published: June 2023

Researchers' attention has recently been on the best ways to integrate Distributed Generation (DG) into the conventional centralized electrical power distribution systems, particularly in the context of the smart grid idea due to its reputation as a viable remedy for the lack of electric power supply. To optimize the environmental, financial, and technological advantages of DG units’ integration for distribution network operators, it is crucial to determine their ideal position and size. The main objective of this study was to develop and simulate an optimization system for the placement and sizing of distributed generation units in electrical power distribution networks for power losses reduction and voltage profile improvement. The specific objectives were to model and develop the load flow algorithm and codes; develop a meta-heuristic optimization algorithm and codes that selects the best location and size of the DG unit; simulate the nested load flow and optimization algorithms and codes on MATLAB and analyze the effectiveness of the developed algorithm via testing on the standard IEEE 33-bus radial electrical power distribution benchmark network. The Backward-Forward Sweep (BFS) technique was employed in the load flow modelling owing to its maximization of the radial structure of distribution systems. The optimization algorithm was developed based on the Multi-objective Particle swamp optimization (PSO) meta-heuristic technique due to its effective global searching characteristic. The line and load data for the IEEE 33-bus test network being a cutting-edge benchmark for contemporary power distribution networks; were obtained from the Power Systems Test Case Archive- a secondary data source. For this network fed by a synchronous generator, the chosen base MVA (Mega Volt Amp) was 10MVA and the base voltage was 12.66kV. The total active and reactive power demand were 3.715MW and 2.3Mvar respectively. The simulation was done on R2021a version of MATLAB/Simulink. The total real and reactive power losses obtained from base case simulation without the placement of any DG unit in the network were obtained as 201.8925kW and 134.6413kvar respectively while the per unit (p.u) average bus voltage was 0.948594 p.u. After the optimal allocation of one, two, three and four DG units, the total real power loss (in kW) in the network reduced by 140.89, 173.89, 189.89 and 195.89 respectively while the total reactive power loss (in kvar) reduced by 86.64, 114.64, 124,64 and 128.64 respectively. Likewise, the per unit average bus voltage improved by 0.0376p. u, 0.0458p.u, 0.0480p.u and 0.0498p.u respectively. Also, the decrease in the total real and reactive power losses and the improvement in bus voltage profiles varies proportionally with the number of DG units optimally placed. In conclusion, the results shows that the total real power loss and the total reactive power loss of the network, were significantly decreased; and the voltage profile of the system was drastically enhanced by incorporating DG units at predetermined buses. The developed algorithm is recommended for application in a real electrical power distribution network for more efficient integration of new distributed generation units in the current electrical power distribution networks.