This article develops a digital mathematical model in symmetrical components to handle multi-pulse converters power system equipped with correction power factor capacitors or shunt passive harmonic filters. The model simulates AC/DC interaction system in both AC and DC sides with balanced and unbalanced AC system voltages and is adapted for general representation of converter transformers to meet Y/, Y/Y, and Y/Z connections. Comparison results with previous works are given with correction power factor capacitors or shunt passive harmonic filters. The results also included the interaction of AC/DC systems resonating with shunt capacitors at one or more of harmonic power-frequency and the resulting zero sequence harmonics due to AC unbalanced voltage.

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Economic load dispatch (ELD) became recently a mandatory tool for reliable and economic power system operation. ELD improves the security of the power supply while minimizing the generation costs. Daily load curve imposes conflicting requirements on ELD scheme, such as fulfilling demand during peak periods while limiting the cost. Demand response (DR) is an intelligent approach that ensures load demand fulfillment without introducing additional costs. DR allows shifting the electricity consumption to the non‐peak periods. Therefore, DR could be considered as a virtual power plant. ELD is usually solved as nonlinear constraint optimization problem. Three simple, fertile, and robust meta‐heuristic optimizations are competing in this article for solving ELD incorporating DR as virtual power plant. These are ant lion optimizer (ALO), particle swarm optimization (PSO), and artificial immune system (AIS). The objectives are minimizing the overall cost, system losses, and emission levels. Variety of distinctive study systems are considered to test the functionality and feasibility of the proposed algorithms; they are 6‐bus, 30‐bus, and 118‐bus IEEE systems. MATLAB environment is used for coding ALO, PSO, AIS, and the systems under concern. The comprehensive results show that incorporating DR in ELD reduces the costs/losses/emissions without affecting the power system security and reliability. The comparative results verify the robustness and reliability of ALO in minimizing the overall operating cost and emission levels of the power systems under concern while confining with the constraints. Moreover, they show that ALO has the highest accuracy and convergence efficiency while enjoying the reduced computation storage and execution time.

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This study is devoted to understand the mechanisms of mineral fillers in asphalt at the mixture and mastic scales. To do so, the physical properties of asphalt mixtures and mastics were evaluated; in addition, a chemical investigation was presented on the mastic scale for the sake of providing insight behind the possible mechanisms between asphalt binder and mineral filler. Three mineral fillers namely hydrated lime (HL), limestone (LS), and cement bypass dust (CD) were incorporated into an asphalt binder at different filler-to-binder (F/B) ratios. For the mechanistic evaluation of the mixtures, the indirect tensile strength (ITS), moisture damage evaluation, resilient modulus, and static creep-recovery tests were carried out. The fracture energies also were quantified for all the studied mixtures. The results of penetration and softening point tests, as well as their pertinent penetration index (PI), were discussed to elucidate some physical properties of the mastics. The nuclear magnetic resonance (NMR) spectroscopy was performed on the mastics to obtain information on molecular structures of the formed composites. The findings of this study emphasize that the physical properties of mixtures and mastics are highly dependent on type and concentration of mineral filler. The 1H-NMR and 13C-NMR results proved that the inclusion of the studied fillers did not change the molecular structure of the base asphalt binder; hereby the physical mechanisms stand behind the attained properties. It is believed that the findings of this work would contribute to growing knowledge of the mechanisms of mineral fillers in asphalt mixtures.