Long-Term Forecasting of Electrical Loads in Kuwait Using Prophet and Holt–Winters Models

The rapidly increasing population growth and expansion of urban development are undoubtedly two of the main reasons for increasing global energy consumption. Accurate long-term forecasting of peak load is essential for saving time and money for countries’ power generation utilities. This paper introduces the first investigation into the performance of the Prophet model in the long-term peak load forecasting of Kuwait. The Prophet model is compared with the well-established Holt–Winters model to assess its feasibility and accuracy in forecasting long-term peak loads. Real data of electric load peaks from Kuwait powerplants from 2010 to 2020 were used for the electric load peaks, forecasting the peak load between 2020 and 2030. The Prophet model has shown more accurate predictions than the Holt–Winters model in five statistical performance metrics. Besides, the robustness of the two models was investigated by adding Gaussian white noise of different intensities. The Prophet model has proven to be more robust to noise than the Holt–Winters model. Furthermore, the generalizability test of the two models has shown that the Prophet model outperforms the Holt–Winters model. The reported results suggest that the forecasted maximum peak load is expected to reach 18,550 and 19,588 MW for the Prophet and Holt–Winters models by 2030 in Kuwait. The study suggests that the best months for scheduling the preventive maintenance for the year 2020 and 2021 are from November 2020 until March 2021 for both models

Microstructure and microhardness of OFHC copper processed by high-pressure torsion

An ultra-high purity oxygen free high conductivity (OFHC) Cu was investigated to determine the evolution of microstructure and microhardness during processing by high-pressure torsion (HPT). Disks were processed at ambient temperature, the microstructures were observed at the center, mid-radius and near-edge positions and the Vickers microhardness was recorded along radial directions. At low strains, ?3 twin boundaries are formed due to dynamic recrystallization before microstructural refinement and ultimately a stabilized ultrafine grain structure is formed in the near-edge position with an average grain size of ~280 nm after 10 turns. Measurements show the microhardness initially increases to ~150 Hv at an equivalent strain of ~2, then falls to about ~80 Hv during dynamic recrystallization up to a strain of ~8 and thereafter increases again to a saturated value of ~150 Hv at strains above ~22. The delay in microstructure and microhardness homogeneity by dynamic recrystallization is attributed to the high purity of Cu that enhances dislocation mobility and causes dynamic softening during the early stages of straining

Effect of initial annealing temperature on microstructural development and microhardness in high-purity copper processed by high-pressure torsion

The effect of the initial annealing temperature on the evolution of microstructure and microhardness in high purity OFHC Cu was investigated after processing by HPT. Disks of Cu were annealed for one hour at two different annealing temperatures, 400 and 800°C, and then processed by HPT at room temperature under a pressure of 6.0 GPa for 1/4, 1/2, 1, 5 and 10 turns. Samples were stored for 6 months after HPT processing to examine the self-annealing effects. Electron backscattered diffraction (EBSD) measurements were recorded for each disk at three positions: center, mid-radius and near edge. Microhardness measurements were also recorded along the diameters of each disk. Both alloys showed rapid hardening and then strain softening in the very early stages of straining due to self-annealing with a clear delay in the onset of softening in the alloy initially annealed at 800°C. This delay was due to the relatively larger initial grain size compared to the alloy initially annealed at 400°C. The final microstructures consisted of homogeneous fine grain sizes having average sizes of ~0.28 and ~0.34 μm for the alloys initially annealed at 400 and 800°C, respectively. A new model is proposed to describe the behavior of the hardness evolution by HPT in high purity OFHC Cu

Microstructure and microhardness of an Al-6061 metal matrix composite processed by high-pressure torsion

Disks of an Al-6061 metal matrix composite, reinforced with 10 vol.% Al2O3 particles, were processed by high-pressure torsion (HPT) at room temperature for 1/4, 1/2, 1, 5 and 10 turns under an applied pressure of 6.0 GPa. The evolution of microstructure was investigated using optical microscopy and scanning electron microscopy. During HPT processing the average grain size within the aluminum matrix decreased from ? 35 ?m in the unprocessed condition to ? 170 nm after processing through 10 turns but there was no significant effect on the size and distribution of the alumina particulate clusters. The values of the Vickers microhardness were recorded across the surface of each disk and then plotted as two-dimensional and three-dimensional color-coded contour maps. The results show the hardness increases from ? 56 Hv in the initial condition to ? 165 Hv after HPT for 10 turns. The results demonstrate that, as in many unreinforced metallic alloys, the evolution of hardness with strain exhibits strain hardening without any significant recovery

The significance of self-annealing at room temperature in high purity copper processed by high-pressure torsion

High purity copper was processed by high-pressure torsion (HPT) at room temperature and then stored at room temperature for periods of up to 6 weeks to investigate the effect of self-annealing. Hardness measurements were recorded both at 48 h after HPT processing and after various storage times. The results show the occurrence of recovery near the edges of the discs after processing through 1/2 and 1 turn and this leads to a significant drop in the measured hardness values which is accompanied by microstructural evidence for abnormal grain growth. Conversely, there was no recovery, and therefore no hardness drops, after processing through 5 and 10 turns. X-ray line profile analysis was used to determine the crystallite sizes and dislocation densities at 1 h after HPT and after storage for different times. The results show a good thermal stability in high purity Cu after processing through more than 1 turn of HPT but care must be exercised in recording hardness measurements when processing through only fractional or very small numbers of turns

Microstructure and microhardness of an Al-6061 metal matrix composite processed by high-pressure torsion

Disks of an Al-6061 metal matrix composite, reinforced with 10 vol.% Al2O3 particles, were processed by high-pressure torsion (HPT) at room temperature for 1/4, 1/2, 1, 5 and 10 turns under an applied pressure of 6.0 GPa. The evolution of microstructure was investigated using optical microscopy and scanning electron microscopy. During HPT processing the average grain size within the aluminum matrix decreased from ? 35 ?m in the unprocessed condition to ? 170 nm after processing through 10 turns but there was no significant effect on the size and distribution of the alumina particulate clusters. The values of the Vickers microhardness were recorded across the surface of each disk and then plotted as two-dimensional and three-dimensional color-coded contour maps. The results show the hardness increases from ? 56 Hv in the initial condition to ? 165 Hv after HPT for 10 turns. The results demonstrate that, as in many unreinforced metallic alloys, the evolution of hardness with strain exhibits strain hardening without any significant recovery