Optimal sitting and sizing of capacitors for voltage enhancement of distribution systems

This paper presents an optimal sizing and placement procedure for allocation the capacitors to enhance the operation of distribution systems. The choice of critical nodes that are necessary to install capacitors is dependent on loss sensitivity analysis. The sensitivity factors measure the variation of the system power losses in terms of the level of reactive power at variant nodes. The outcome of the suggested sensitivity index leads to determine the most suitable points for the installation of capacitors. Then, the ant colony optimization (ACO) algorithm is used to obtain the optimal sitting and sizing of fixed capacitors to enhance the economical and technical benefits of the distribution systems at lowest costs and improved voltage profile compared to the uncompensated systems. The load flow calculations are carried out using the backward/forward sweep (BFS) algorithm. Numerical applications are applied to standard test systems as 15-bus and 34-bus radial distribution systems. The obtained results prove the capability of the proposed placement strategy to allocate fixed capacitors with reduction of the system losses compared to the uncompensated one. Also, more economical solutions with saving in the operating generation costs are achieved. Moreover, comparative studies are introduced to prove the capability and competitive performance of the proposed method with those reported in the literature.