Sine-Cosine Algorithm for Optimal Capacitor Allocation in Distribution Systems Operating Under Non-Sinusoidal Conditions

The rapid increase in the use of nonlinear loads that inject harmonics into electrical distribution systems causes many power quality problems. A practical method to mitigate harmonic distortion and improve the system's technical performance is optimal capacitor allocation. This method aims to get the best value of installed shunt capacitors and also the best location of them while putting the financial aspect into consideration. To accurately optimize these shunt capacitors' size and location, achieving the minimum annual cost and considering IEEE Std. 519™-2014 constraints in distorted systems, optimization problem formulation, is needed. In the literature, many studies discussed this problem. However, most of them formulated their optimization technique based on the fundamental load flow while assuming that the distribution system's loads are operating at sinusoidal conditions, leading to inaccurate analysis of the system and erroneous actions. In this paper, the decoupled harmonic power flow approach (DHPF) is considered the base of the optimization problem, in which the so-called sine-cosine algorithm (SCA) is employed in this work on an 18-bus system working at non-sinusoidal conditions. The results obtained have been compared to obtained results by other optimization techniques to verify the algorithm's effectiveness.