Search Results (873)

In response to the decline in the inertia level of the power system caused by the large-scale integration of new energy, this paper proposes a grid-side pumped storage configuration strategy considering inertia constraints. The general pumped storage configuration ignores the duration of pumped storage and selects only single-duration units for capacity and power configuration. A single unit cannot balance rapid frequency response and long-term energy transfer, forcing thermal power to operate at high costs continuously to provide inertia support, while also causing a sharp increase in wind and solar power curtailment. This paper breaks through the limitations of the traditional single-duration pumped storage configuration and proposes a configuration-operation collaborative optimization strategy that combines inertia constraints and pumped storage duration selection. Firstly, starting from the system’s inertia requirements, the minimum inertia required by the system is obtained, respectively, based on the constraints of the system’s frequency change rate and the lowest point of the frequency. Furthermore, the minimum inertia demand constraint of the power system is constructed, and a capacity configuration strategy for grid-side pumped storage is proposed with the goal of minimizing the total operating cost of the power system throughout its entire cycle, taking into account the penalty term of the peak-valley difference index of the load curve and the penalty of the inertia guarantee value of medium and long-term units, while considering the inertia constraint. Finally, the effectiveness and superiority of the proposed method were verified through simulation analysis. Full article

Building Information Modeling (BIM) is increasingly used to support green building design practices, yet its alignment with established green building assessment (GBA) tools remains underexamined. This study evaluates the extent to which Autodesk Revit, as a BIM tool, supports the calculation of energy-related indicators in GBA tools such as the Leadership in Energy and Environmental Design (LEED) method. A quasi-empirical, multi-method approach was employed, combining content analysis, a Revit-based simulation of a residential building, and structured evaluation by a panel of four experts. Using both subjective and objective measures, the experts assessed Revit’s effectiveness and the role of Revit’s media channels—modeling, simulation, data integration, and text documentation—in supporting and calculating LEED Energy and Atmosphere (EA) indicators. Results reveal that Revit is capable of effectively supporting 7 out of 11 LEED EA indicators. The highly supported indicators included minimum energy performance, building-level energy metering, optimized energy performance, advanced energy metering, renewable energy production, and enhanced refrigerant management while the fundamental refrigerant management indicator was evaluated as a moderately supported indicator. These highly supported indicators are core energy-related indicators; three of them are prerequisite indicators, while the remaining are credit indicators that cover 66.7% of the weight assigned for the EA indicators. The results also demonstrated that the remaining four indicators—fundamental commissioning and verification, enhanced commissioning, demand response, green power, and carbon offsets—were evaluated as poorly supported by Revit. The consistency of results across two rounds of survey, along with the expert’s consensus on 73% (8 out of 11) of the examined indicators, provides empirical validation of Rivet’s capacity to support LEED GBA. Findings also showed that modeling and simulation, followed by data integration, are the most impactful channels in supporting and calculating LEED EA criteria and requirements, with significant statistical correlation confirmed through Kendall’s Tau correlation. The findings have theoretical and practical implications for designers, green building practitioners, and BIM developers and suggest areas for further research. Full article

Bioclimatic monitoring at vineyard scale is essential for irrigation management and disease-risk assessment, yet many systems rely on expensive commercial stations or generic IoT nodes with limited validation and little focus on small and medium-sized winegrowers. This application-driven engineering work investigates whether decision-support-grade bioclimatic data for precision viticulture can be obtained from a low-cost station, by proposing a solar-powered proximal node that integrates soil, plant, and atmospheric sensors on a dedicated PCB that communicates via LoRaWAN. The node operates in a 15-min cycle, with sensing parameters selected to provide the minimum information required for key Precision Viticulture applications. It was deployed in a commercial vineyard side by side with a commercial station, quantifying sensor agreement, communication reliability, and energy consumption. The results show low error rates and consistent agronomic interpretation of environmental conditions, disease risk, precipitation events, and soil and water dynamics. The LoRaWAN link reached a 97% packet-delivery ratio with an average consumption of about 2.5 Wh per day. Material cost is approximately 260 €, one order of magnitude lower than a comparable station. These results indicate that, under real vineyard conditions and compared with a commercial reference, the proposed low-cost system provides agronomically useful, reliable bioclimatic monitoring. Full article

The safe operation of drainage pumping stations, which are core flood-control facilities in eastern coastal areas of China, is paramount due to frequent typhoons and short-duration heavy rainfall. To enhance the operational safety against water hammer during pump trips caused by power failure, a water hammer protection method based on the combined application of flap valves and sluice gates is proposed. Only the scenario of all pumps tripping simultaneously was considered. A one-dimensional simulation model of the pumping station’s hydraulic transient process, which included pumps, pipelines, flap valves, and sluice gates, was established to analyze the system response under three scenarios: (i) only the flap valve closes normally, with the sluice gates remaining open, (ii) the flap valve fails, only the sluice gates operate, and (iii) the combined application of flap valve and sluice gates. In scenario (i), the maximum and minimum channel pressure heads were 13.53 m and −2.22 m, respectively, with no pump reversal occurred. However, continuous pressure fluctuations were observed downstream of the flap valve, posing a threat to the flow channel’s safety. In scenario (ii), the channel pressure heads all met the control requirements. Employing a 60 s single-stage linear closure rule for Gate #1 maintained the pump’s reverse speed within the safe range, peaking at −147.25% of the rated speed, with a reversal duration of 60 s. In scenario (iii), all channel pressure heads met basic control requirements, and no pump reversal occurred. The optimal strategy was found to be the adoption of a 60 s single-stage linear closure rule for both sluice gates. Compared to the scenario (i), the combined application reduced the amplitude of pressure fluctuations and damped these fluctuations rapidly, thus shortening the oscillation duration. The combined approach innovatively utilizes existing infrastructure for water hammer control, providing an economical and reliable solution for water hammer protection in urban drainage pumping stations. Full article

This paper introduces a novel control archetype designed to mitigate high-altitude electromagnetic pulse (HEMP) $E_3$ disturbances on the power grid, as well as information on performance and specifications of different control laws for the controller archetype. This method of protection has been overlooked in the literature until now. A controlled voltage supply is placed on the load-side of a transformer, diverting unwanted power from the transformer core to prevent saturation. The controlled voltage source is modeled using four control laws: an integral controller (capacitor), Linear Quadratic Regulator (LQR), an energy storage minimized feedforward control law, and a Hamiltonian feedback law. Results show that the Hamiltonian feedback law and the energy storage minimization feedforward control law both flat-line magnetic flux with similar actuator requirements. The LQR approach requires less energy storage than the other two laws, depending on control tuning, as it allows greater exogenous current flow through the neutral path to ground. This leads to further optimization opportunities based on acceptable exogenous current levels. A sweep of different LQR gains revealed a reduction of approximately $32\%$ in minimum control effort, $47\%$ in minimum power to maintain saturation bounds, $20\%$ in energy storage requirements, and $59\%$ in required controller bandwidth. Voltage and bandwidth requirements of the load-side controller are comparable to neutral blocking requirements with energy and power requirements being higher for the load-side controller. This, however, comes with the benefit of being able to use pre-existing assets—neutral blocking devices have not been deployed. Additionally, the load-side blocking capacitor degrades transformer performance compared to the unmitigated system. Full article

The energy–water–carbon (EWC) nexus has become a critical concern for industrial systems seeking sustainable development, yet existing assessment approaches often require intensive computation and lack practical adaptability. This study proposes a probability-pinch analysis (P-PA) framework that enhances conventional pinch analysis (PA) by integrating allocation-based correction factors to account for system inefficiencies across all time intervals explicitly. The framework incorporates PA tools, specifically the Power Cascade Table (PCT), Water Cascade Table (WCT), and Energy Planning Pinch Diagram (EPPD), to design ideal energy–water systems that do not consider losses. Correction factors based on probable energy and water flows are then incorporated to capture system inefficiencies, with design modifications proposed to meet annual carbon reduction targets. Results from an industrial plant case study validate the effectiveness of P-PA in establishing minimum resource targets while achieving a 46% reduction in carbon emissions through system modifications. Deviations from conventional PA were within 10%, confirming the framework’s accuracy and reliability in designing integrated energy–water systems within the EWC nexus. It could serve as a handy tool for designing large-scale energy–water systems that require substantial computational effort, but it may be less accurate for small-scale applications. Nevertheless, compared with conventional PA-based approaches, P-PA offers a balanced combination of rigor, simplicity, and adaptability, making it well-suited for industrial EWC nexus analysis and decision support in sustainable process design. Full article

The study of cotton stalk extraction resistance provides important parameters for the design of cotton stalk harvesting machinery. To investigate the effects of soil moisture content, cotton stalk diameter, and extraction angle on the extraction force of densely planted cotton stalks, this paper designs a real-time measurement system based on virtual instrument technology and conducts field tests. The tests were carried out in cotton fields at the First Farm in Aral City, Xinjiang, using the cotton variety “Xiulu Zhong 70”. Single-factor experiments were conducted with extraction angle and stalk diameter as influencing factors. A combined three-factor experiment was performed under the following conditions: soil moisture contents of 21.87% and 26.32%; extraction angles of 25°, 30°, and 35°; and cotton stalk diameters of 8.50–9.00 mm, 10.00–10.50 mm, and 11.50–12.00 mm. The results show that the minimum extraction force is required when the extraction angle is 30°. Soil moisture content significantly affects the extraction force, which increases with stalk diameter. The combined test results indicate that the order of significance of the three factors is as follows: cotton stalk diameter (A), extraction angle (B), and soil moisture content (C). The optimal combination is A₁B₁C₂, corresponding to a diameter of 8.50–9.00 mm, an extraction angle of 35°, and a soil moisture content of 26.32%. Based on comprehensive analysis, the recommended extraction angle range is 30–35°. The proposed system can efficiently complete cotton stalk extraction force tests, and the collected data provide valuable references for the design of cotton stalk harvesting machinery. By appropriately selecting the extraction angle and conducting harvesting under suitable soil moisture conditions, it is possible to reduce power consumption and improve production efficiency. Full article

Power converters are essential for solar energy systems but achieving over 96% efficiency at 1 kW and 300 kHz with compact magnetic and EMC compliance remains challenging for high-power-density PV applications. This study presents the design, modeling, and experimental validation of a 1 kW two-phase interleaved boost converter operating from 12 V input to 48 V/20 A output, featuring a single EE32 Litz-wound coupled-core inductor with coupling coefficient k = −0.475 that reduces per-phase current ripple to just 120 mA (0.6% relative) at full load, a load-selective active zero-current switching (ZCS) circuit activated above 5 A threshold via DCR sensing to minimize switching losses without light-load penalties, and digital peak-current control with 2P2Z compensator implemented on an XMC4200 microcontroller, ensuring robust stability. Experimental results demonstrate peak efficiency of 98.6% at approximately 190 W load, full-load efficiency of approximately 96% with total losses limited to 40 W dominated by conduction rather than switching, thermal rise below 80 °C on key components, voltage regulation with less than 1% deviation down to 2 A minimum load, and full compliance with electromagnetic compatibility standards, including EN 55014-1/2 and EN 61000-4-2 ESD testing. The novel integration of selective ZCS, single-core magnetic, and high-frequency operation outperforms prior interleaved boost converters, which typically achieve 94–97% peak efficiency at lower switching frequencies of 20–100 kHz using multiple inductors or complex always-active resonant networks, making this solution particularly suitable for compact photovoltaic micro-converters, electric vehicles, and industrial power supplies requiring high efficiency, reliability, and regulatory compliance. Full article

To address the challenges to power system frequency stability under high penetration of renewable energy, this paper proposes a coordinated inertia support strategy for wind–PV–thermal storage systems, overcoming the limitations of conventional inertia parameter adjustment. The core of the strategy lies in optimizing unit control activation logic and establishing a scenario-adaptive batch activation mechanism. Specifically, virtual inertia characteristic models for wind, PV, and storage units are developed, with key parameters optimized via fuzzy-logic-based coordinated control. An inertia demand assessment model under frequency security constraints is constructed to quantify the minimum system inertia requirement. Furthermore, disturbance reference power is generated based on the inertia reserve capability of each unit, and disturbance intervals are classified to achieve coordinated optimal allocation of virtual inertia. Simulation results on a built 3-machine, 9-node system demonstrate that the proposed strategy can intelligently coordinate the activation timing, role assignment, and regulation resources of wind, PV, and storage according to the type and severity of disturbances. Under various scenarios such as sudden load increase and decrease, the system effectively mobilizes resources to maintain frequency within the secure range while avoiding frequent actions of any single unit. The results verify that the strategy significantly enhances the system’s capability to handle bidirectional power disturbances and provide frequency support, offering a practical solution for inertia management in renewable-dominated power systems. Full article

This study optimizes the placement of μ-PMUs using the BPSO and BGWO algorithms for the IEEE 33-bus and 69-bus systems, with a focus on minimizing deployment costs while ensuring robust system observability. Three case studies are analysed: Case 1 (normal conditions), Case 2 (single μ-PMU outage), and Case 3 (Zero Injection Buses, ZIBs). In Case 1, both algorithms identified 24 μ-PMUs as the optimal placement for the IEEE 69-bus system, achieving the minimum PMUs required for full observability. For Case 2, redundancy requirements increased the μ-PMU count to 24 μ-PMUs for the IEEE 33-bus system and 51 μ-PMUs for the IEEE 69-bus system, ensuring full observability even under a single μ-PMU failure. Case 3, leveraging Zero Injection Buses (ZIBs), reduced the μ-PMU count to 20 μ-PMUs for both BPSO and BGWO, optimizing the system configuration while maintaining observability. A trade-off analysis was performed to examine the trade-off between redundancy and PMU count, showing that increasing the number of μ-PMUs improves system resilience. Voltage and current channels were measured from the optimized placements to ensure accurate voltage measurement in all case studies. Subsequently, the Weighted Least Squares algorithm was applied for voltage estimation, serving as a peripheral to the main objective of the optimal μ-PMU placement. Voltage estimation was conducted under three noise levels: 0.01 STD for basic analysis and 0.02 and 0.04 STD to observe the impact of varying measurement noise. The results highlight that higher μ-PMU placements improve voltage estimation accuracy, particularly under higher noise levels. Statistical analysis confirms that BGWO outperforms BPSO in terms of computational efficiency, stability, and convergence, especially in large-scale systems. By enhancing grid monitoring and state estimation, this research directly contributes to the development of more resilient and efficient power networks, which is a fundamental prerequisite for integrating renewable energy sources and advancing overall power system sustainability. This research emphasizes the balance between cost and reliability in μ-PMU placement and provides a comprehensive methodology for state estimation in modern power systems. Full article

Energy efficiency in road lighting is increasingly critical for sustainable urban development, yet numerical indicators essential for objective evaluation are often misunderstood or misapplied. This paper addresses fundamental misconceptions in interpreting the Power Density Indicator (PDI), a key metric for assessing lighting system efficiency. Through analysis of Romanian street lighting modernization projects and extensive literature review, we demonstrate widespread misunderstanding of PDI’s properties, including inappropriate summation across streets and failure to recognize its independence from road class. We present a comprehensive methodology for PDI interpretation and optimization through spatial visualization of Luminous Intensity Distribution Curves (LIDCs) using MATLAB’s MESH function. The theoretical framework derives minimum achievable PDI values as a function of LED-specific efficacy and system utilance. Case studies from 181 streets in Romanian cities reveal significant optimization potential. Finally, we demonstrate, through computational simulation, the theoretical ideal: a perfectly adapted LIDC achieving unitary utilance, confirming that minimum PDI depends solely on LED efficacy and optical efficiency. These findings provide practical guidance for designers to optimize energy efficiency while meeting photometric requirements. Full article

The Ising model is able to memorize some patterns or solutions as stable states. An Ising network may automatically converge to a pre-stored solution for a random input. However, in many cases, the Ising model cannot perform this task. The gap is that for a set of desired patterns, one may not be able to construct an Ising model such that the desired patterns are the stable solutions of the Ising model. The Ising model has limited power, because its energy function is limited to a second-order polynomial. Our research outline is as follows. This paper extends the conventional Ising model so that it has wider applications, where the Hebbian rule no longer works. The extended model does not have a limit on the order of the energy function. The extended Ising is defined by combining all desired patterns in a product. Our findings are that the extended Ising model has explicit closed-from update formulas, which do not require the evaluation of gradients. Thus, no network training is necessary. The update algorithm takes finite steps to reach a local minimum. Full article

Micro–nano-sized processing equipment requires high levels of precision, necessitating residual stress measurement to maintain stability. Ultrasonic stress measurement is an effective method but is hindered by high sampling-rate requirements, leading to excessive power consumption and hardware costs. This study presents a low-sampling-rate method based on the novel Frequency-domain Zero-padded Cross-correlation Time Delay Estimation (FZC-TDE) algorithm. Tensile validation experiments determined the minimum hardware sampling-rate requirement: rates below 25 MSps (even with interpolation) fail to characterize temporal delay variations effectively, and a rate of at least 20 times the signal frequency is required for ±10 MPa accuracy. The proposed FZC-TDE utilizes a frequency-domain fusion operation (frequency-domain zero-padding interpolation combined with cross-correlation) to enable real-time, high-resolution delay measurement at low rates. Comparative experiments show that time-domain interpolation methods (Linear, PCH, Cubic Spline) achieve similar stress estimation accuracy at the same rate (e.g., 7.4–8.7 MPa error at 100 MSps), while FZC-TDE (10.3 MPa error) offers superior computational efficiency. At 100 MSps, FZC-TDE maintains a stable computation time (~2.8 ms), while those of interpolation methods increase significantly (20–30 ms) due to higher oversampling factors. Furthermore, FZC-TDE reduces the number of arithmetic operations by 75% (2.26 million vs. ≥9.18 million for 128× oversampling on 1024 points) and exhibits slower computational load growth with oversampling ratios. Thus, FZC-TDE provides an optimal balance of acceptable accuracy and significantly enhanced efficiency, particularly for real-time or resource-constrained applications. This work reduces sampling-rate constraints and supports advancements in micro–nano-sized processing equipment and device performance. Full article

Time-mode digital pixel sensors have several advantages in Internet-of-Things applications, which require a compact circuit and low-power operation under poorly illuminated environments. Although the time-mode digitization technique can theoretically achieve a wide dynamic range by overcoming the supply voltage limitation, its practical dynamic range is limited by the maximum clock frequency and device leakage. This study proposes an extended time-mode digitization technique and a low-leakage pixel circuit to accommodate a wide range of light intensities with a small number of digital bits. The prototype sensor was fabricated in a 0.18 μm standard CMOS process, and the measurement results demonstrate its capability to accommodate a 0.03 lx minimum light intensity, providing a dynamic range figure-of-merit of 1.6 and a power figure-of-merit of 37 pJ/frame·pixel. Full article

Energy storage systems (ESSs) have recently emerged as a common solution for mitigating the variability of intermittent renewable energy sources. A major challenge linked to ESSs is their expense. This study focuses on investigating techniques to decrease the size of an ESS while maintaining its performance levels. Data were gathered from a grid-connected 2MW PV system in Malaysia over multiple days, with numerous variables showing considerable hour-to-hour variations from hour to hour due to solar irradiation. A Python code was created to examine the impact of different ESS sizes on power grid stabilization utilizing the power conservation technique. The suggested ESS size derived from the program outcomes was evaluated utilizing a hybrid ESS, incorporating a vanadium redox battery (VRB) as the high-energy-density component and supercapacitors (SCs) as the high-power-density component. The effects of altering the output period lengths were examined. The result must stay consistent for at least five minutes as the minimum required duration. The findings show that an ESS capacity of approximately 10% of the overall produced power can meet the above duration requirement. A straightforward test was employed in the system to assess the power generation level in the upcoming time period. Simulink was employed to model the produced system, and the outcomes met the ESS requirements, enhancing efficiency and extending the battery lifespan. Full article