This paper presents an experimental comparative analysis of electromechanical, static, and microprocessor-based protective relays using the secondary injection testing method. The study evaluates key performance indicators, including pickup current, dropout current, and operating time, under controlled laboratory conditions. The results show that electromechanical relays exhibit pickup current deviations below 5\%, accompanied by relatively high variability in operating time (up to 0.2 s), mainly due to inherent mechanical limitations. Static relays demonstrate improved performance, with enhanced stability, reduced deviations, and limited time variation within ±0.1 s. Microprocessor-based r... More >

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),... More >