This paper discusses the problem of optimal placement and sizing of passive harmonic filters to mitigate harmonics in unbalanced distribution systems. The problem is formulated as a nonlinear multiobjective optimisation problem and solved using the multiobjective genetic algorithm. The performance of the proposed algorithm is tested on unbalanced IEEE 13- and 37-bus three-phase systems. The optimal solutions are obtained based on the following objective functions: 1) minimisation of total harmonic distortion in voltage, 2) minimisation of costs of filters, 3) minimisation of voltage unbalances, and 4) a simultaneous minimisation of total harmonic distortion in voltage, costs of filters, and voltage unbalances. Finally, an analysis of the influence of uncertainties of load powers and changes in system frequency and filter parameters on filter efficiency was performed.

The problem of optimising the thermal environment and design parameters of underground cable lines for cable crossings with the aim of increasing the ampacities of cables is considered in this paper. Particle swarm optimisation (PSO) algorithm, formulated as a continuous non‐linear optimisation problem with constraints, for solving this hot spot problem is applied. It is found, using the PSO algorithm, that there are a suitable size of cable bedding and an arrangement of cables within that bedding, which can eliminate or significantly mitigate the hot spot effect without the use of any additional cooling equipment. In this manner, the ampacities of both crossing cable lines increase by about 15% on average with respect to the case of a similar crossing with installation parameters commonly used. In addition, it is shown how the cross‐sectional areas of the conductors and metal screens and the metal screen bonding methods affect the optimal solution.

This paper presents a Taguchi-tuned Particle Swarm Optimization (PSO) approach for the optimal placement and sizing of shunt capacitor banks (CBs) in unbalanced distribution systems. The optimization aims to minimize the total operational cost by reducing power losses and improving voltage profile. A systematic parameter tuning was carried out using the Taguchi method based on an L25 orthogonal array, with five PSO parameters evaluated through Signal-to-Noise (SN) ratios and Analysis of Variance (ANOVA). The IEEE 13-bus test feeder was used as a benchmark. The results show that the installation of four optimally placed CBs reduces active power losses by 29.6% (from 133.16 kW to 93.71 kW), improves the minimum bus voltage from 0.942 p.u. to 1.014 p.u., and decreases operating costs by 6,144.55$ compared to the base case. Validation using DIgSILENT PowerFactory confirms the consistency of the proposed method. Moreover, the Taguchi-optimized PSO demonstrated superior performance over the classical PSO in terms of convergence speed, solution quality, and result consistency across multiple independent runs, confirming its effectiveness and robustness for practical distribution system optimization.