System Load Research Articles

Optimal turning of a 2-DOF proportional-integral-derivative controller based on a chess algorithm for load frequency control

Load frequency control is necessary for power system management. The power system must maintain a frequency range to ensure power supply stability. System faults and demand fluctuations may cause frequencies to change quickly. System stability and integrity suffer. We are optimizing the two-degree-of-freedom (2-DOF) proportional-integral-derivative (PID) controllers chess algorithm. This article addresses electrical load frequency regulation. We employ classical control theory and current adjustment. It aims for electrical system efficiency and dependability. It checks for errors using integral absolute error (IAE), integral squared error (ISE), integral of time multiply absolute error (ITAE), and integral time squared error (ITSE). Particle swarm algorithm (PSO) compares performance. The IAE of 0.03364, nearly identical to it, shows that chess trumps other algorithms in many scenarios. The chess algorithm's ISE was 0.00035, like PSO's 0.03363. The ISE was 0.00036, indicating PSO's error-reduction capabilities. For the chess algorithm, PSO is 0.07929, and ITAE is 0.07647. This indicates the PSO responds faster to system breakdowns and load changes. Finally, the chess algorithm's ITSE is 0.00072, below the PSO 0.00076. The chess algorithm is better at managing long-term load frequency.

An in vitro nanocarrier-based B cell antigen loading system; tumor growth suppression via transfusion of the antigen-loaded B cells in vivo.

B cell-based vaccines are expected to provide an alternative to DC-based vaccines. However, the efficacy of antigen uptake by B cells in vitro is relatively low, and efficient antigen-loading methods must be established before B cell-based vaccines are viable in clinical settings. We recently developed an in vitro system that efficiently loads antigens into isolated splenic B cells via liposomes decorated with hydroxyl PEG (HO-PEG-Lips). Therefore, the purpose of this study was to expand this system in order to achieve another approach to in vivo tumor growth suppression. By using HO-PEG-Lips as a carrier for model antigen OVA along with an adjuvant, α-galactosylceramide (GC), the amount of antigen loading to the B cells in vitro was increased compared with that of both free OVA and free GC. Transfusion of B cells treated with HO-PEG-Lips that encapsulated OVA and GC suppressed the growth of OVA-expressing murine thymoma (E.G7-OVA) tumors in vivo through strong induction of OVA-specific T cells. Under fluorescence microscopic observation, migration of the transfused B cells in the spleens of recipient mice were confirmed. Our results indicate that our novel antigen-loading system could become a promising approach to facilitate the development of cell-based therapeutic cancer vaccines utilizing B cells as alternative APCs.

“One Pot” Enzymatic Synthesis of Caffeic Acid Phenethyl Ester in Deep Eutectic Solvent

Caffeic acid phenethyl ester (CAPE) represents a valuable ester of caffeic acid, which, over time, has demonstrated remarkable pharmacological properties. In general, the ester is obtained in organic solvents, especially by the esterification reaction of caffeic acid (CA) and 2-phenylethanol (PE). In this context, the purpose of this study was the use of the “one pot” system to synthesize CAPE through biocatalysis with various lipases in a choline-chloride-based DES system, employing the “2-in-1” concept, where one of the substrates functions as both reactant and solvent. The synthesis process of CAPE is contingent on the molar ratio between CA and PE; thus, this factor was the primary subject of investigation, with different molar ratios of CA and PE being studied. Furthermore, the impact of temperature, time, the nature of the biocatalyst, and the water loading of the DES system was also examined. This ‘green’ synthesis method, which has demonstrated encouraging reaction yields (%), could secure and maintain the therapeutic potential of CAPE, mainly due to the non-toxic character of the reaction medium.

Horizontal Cyclic Bearing Characteristics of Bucket Foundation in Sand for Offshore Wind Turbines

During the service period, the offshore wind turbine foundation mainly bears the wind load from the upper structure and the periodic loads such as wave load and sea currents from the lower structure. Long-term cyclic loads have an important impact on the cumulative deformation, foundation stiffness changes, and horizontal ultimate bearing capacity of the offshore wind turbine bucket foundation. This paper conducts cyclic loading tests on mono-bucket foundations under unidirectional and multidirectional cyclic loading conditions based on the multidirectional intelligent cyclic loading system of offshore wind turbine foundations and analyzes the cumulative effects of the loading direction, vertical load, and drainage status on the mono-bucket foundation during the cyclic loading process, effects of rotation angle, cyclic stiffness, and monotonic bearing capacity of foundation after cycles. The research results show that multidirectional cyclic loading significantly reduces the cyclic cumulative rotation angle of the mono-bucket foundation, and the maximum reduction rate can reach more than 50%. After unidirectional and multidirectional cyclic loading, the bearing capacity of the bucket foundation can be increased by up to 30% and 20%, respectively. At the same time, this paper proposes calculation formulas for vertical load, number of cyclic loading, and normalized cumulative rotation and establishes a calculation method for vertical load and bearing capacity of the foundation after cycles.

Research on optimization of power system load response strategy and cost–benefit analysis based on electricity price algorithm model

Abstract This article proposes an innovative framework that amalgamates deep reinforcement learning (DRL) with cost–benefit analysis (CBA). The enhanced actor–critic DRL algorithm simultaneously addresses short-term price fluctuations and long-term system benefits, facilitating optimization across multiple time scales. Furthermore, it establishes a dynamic, multidimensional CBA model that encompasses a comprehensive evaluation of economic, social, and technological benefits, employing a fuzzy comprehensive evaluation method for quantitative analysis. The integration of DRL and CBA forms a closed-loop system that continuously refines strategy optimization through real-time adjustments of the reward function and evaluation weights. Experimental results validate the efficacy of this approach.

Longitudinal joint in decked bulb‐tee beams for accelerated bridge construction with ribbed GFRP bars: Ultimate load and fatigue evaluation

AbstractAccelerated bridge construction (ABC) techniques have gained prominence due to their potential to minimize construction time and traffic disruptions while enhancing sustainability. This study investigates the use of ultra‐high‐performance concrete (UHPC) and glass fiber‐reinforced polymer (GFRP) bars to address critical challenges in bridge durability and longevity. A novel UHPC‐filled precast deck joint was developed for a decked bulb‐tee (DBT) girder system, utilizing GFRP bars to eliminate corrosion‐related issues typical of steel reinforcement. Two actual‐size, GFRP‐reinforced, precast concrete deck slabs were erected to perform fatigue tests using the footprint of the Canadian Highway Bridge Design Code (CHBDC) truck wheel loading to verify the design. Each slab had 200 mm thickness, 2500 mm width, and 3500 mm length in the direction of traffic and rest over braced twin steel girders. The closure strip between connected precast slabs has a width of 125 mm with a vertical shear key. GFRP bars in the precast slab projected into the closure strip with a headed end to provide a 100 mm embedment length. Two types of fatigue tests were performed (i) accelerated variable amplitude cyclic loading and (ii) constant amplitude cyclic loading, followed by loading the slab monotonically to failure. Results demonstrated the system's superior fatigue performance and high ultimate load capacity, making it a promising solution for durable, efficient bridge construction.

Voltage profile enhancement of an AVR system using Ant Lion Optimization algorithm

Abstract This paper addresses voltage regulation, which is a critical issue in power systems. The automatic voltage regulator (AVR) plays a crucial role in maintaining voltage regulation within permissible limits The AVR system's dynamic behaviour is improved by applying the Proportional (KP) Integral (KI) Derivative (KD) (PID) controller. The primary challenges of using a PID controller in AVR include difficulties in tuning parameters to handle nonlinearities, load disturbances, and system dynamics, leading to potential instability, overshoot, or slow response. The controller parameters are tuned with Ant Lion Optimisation (ALO) algorithm and Integral Time Absolute Error (ITAE) as an objective function. Also, the proposed system has the ability to improve the transient response of AVR by decreasing the maximum overshoot, settling time, rise time, and peak time magnitudes of the generator terminal voltage with eliminating the steady state error. Once the suggested method had produced the best values for the three gains i.e., KP, KI, and KD of the PID controller, a transient response analysis is examined and compared with some of the existing techniques such as Bat Algorithm (BA), Grey Wolf Optimisation (GWO) and Biogeography Based Optimisation (BBO) algorithm to highlight the novelty of the proposed ALO optimized PID controller. Transient response analysis, root locus analysis, and bode analysis are used to assess the AVR system's stability. Comparisons to three well-known optimization techniques corroborate the findings. The results show that this new suggested method performs exceptionally well even when there are significant variations in power system parameters and load uncertainties.

Optimal On-Load Tap Changer Tap Control Method for Voltage Compliance Rate Improvement in Distribution Systems, Based on Field Measurement Data

This paper proposes an optimal control method for the on-load tap changer (OLTC) of a substation’s main transformer (M.TR), to maximize the voltage compliance rate (VCR) in distribution system feeders. The conventional auto voltage regulator (AVR)’s line-drop compensation (LDC) control method struggles with accurately determining load centers and has limitations in managing voltage due to the variability of distributed energy resources (DERs). To address these challenges, this study defines sample number-based VCR (SNB-VCR) as the performance index function to be maximized. The optimal tap positions for the OLTC are obtained using the gradient ascent method. Since the SNB-VCR evaluates voltage compliance using 15 min interval data collected from all the load and DER connection points in the distribution system, the tap position obtained by the gradient ascent method maximizes voltage quality for every feeder included in the system. Using a simulation, it is verified that the proposed tap control method improves the overall voltage quality and reduces the occurrence of overvoltage or undervoltage compared to LDC control. The proposed control strategy offers a practical solution for enhancing voltage management efficiency in modern distribution systems, particularly those with high penetration of DERs.

Analysis of power load composition and study on countermeasures for orderly use of electricity

The electric power industry is the foundational industry of national economic construction and is closely associated with people's lives. The development and improvement of the economy have led to this. Moreover, society has increasingly higher demands for the reliability of power supply and the qualification rate of voltage. Power load control technology is a comprehensive use of modern management, automatic control, computer application and other disciplines to carry out power marketing management, power marketing monitoring, business copy and collection, data collection and other activities of a technology, and substation as a local industrial and agricultural production, life power supply base, the rationality of its design will directly affect the local economic development. To build a new type of power system, achieve the goal of carbon peaking and carbon neutrality, realize the flexible interaction of the new type of power system load, and meet the requirements of the digital transformation of power load management, this paper examines the architecture of the new type of power load management system from the perspective of the concept of the new type of power load management system. Then it focuses on the analysis of several key information and communication technologies, including cloud computing technology and artificial intelligence technology, which support the new power load management system in the power load management system, and introduces the composition of the load management system and the application algorithm, and finally puts forward the future development of the new power

Asymmetry Between Queues with Correlated Service and Correlated Arrivals

It is known that a correlation in either the service or interarrival times causes a deterioration in the performance of a queuing system. This study aimed to determine which of the two correlations—in the service times or in the interarrival times—has a stronger influence on the expected queue length, assuming an identical autocorrelation function in both cases. To achieve this goal, a formula for the expected queue length in a system with correlated arrivals was derived first. This new formula, along with a known formula for the expected queue length in a system with correlated service, was used to compare the influence of the two correlations. Various scenarios were studied, such as cases where the common correlation was positive or negative, where the variance of the service or interarrival time was low or high, and where the system load was low or high. Furthermore, both the time-dependent and the steady-state behaviors of the systems were compared. The following two key observations were made. If the impact of other factors on the queue length is minor, then a positive correlation has a worse effect on the queue length when present in service times than in arrival times. On the contrary, a negative correlation has a worse effect on the queue length when present in arrival times than in service times.

Trading Incentive Mechanism and Response Model for High-Frequency Interaction Between Virtual Power Plants and Main Grid Under Spot Markets

As the energy market moves toward decentralization and high-frequency trading, virtual power plants’ (VPP) involvement in and responsiveness to the spot market — an integration platform for dispersed and renewable energy resources — has grown significantly. The response model and trading incentive mechanism for high-frequency interactions between VPPs and the main grid under the spot market are covered in this study. First, a theoretical analysis of market participation incentives is conducted, taking into account variables, including market participation, response speed, and influence, as well as the design principles of reward and compensation schemes. Second, a data-driven forecasting and optimization model is put out to address how VPPs react in real time to variations in energy prices and system load. There is more discussion about the significance of technical infrastructure, focusing on the integration and optimization of data processing and communication systems. To ensure that VPPs participate in market transactions fairly and transparently, the critical responsibilities of market risk management and regulatory compliance are finally examined. This study combines the viewpoints of market regulation, technology innovation, and economics to offer theoretical underpinning and useful advice for comprehending and maximizing the functions and effects of VPPs in contemporary energy markets.

Microbial Nitrogen Removal in South San Francisco Bay: Does It Play a Role in Eutrophication Resistance?

The ecosystem response to anthropogenic nitrogen (N) loading in estuarine systems is determined by hydrodynamics, biogeochemical transformation rates, and other system-specific characteristics. Historically, San Francisco (SF) Bay has been an outlier from other estuaries with an unusual resistance to eutrophication, despite having extremely high rates of nitrogen loading. Recent increases in phytoplankton biomass and an unprecedented harmful algal bloom, however, have increased the urgency to understand rates and drivers of nitrogen removal in the system. To assess benthic N cycling rates, we conducted seasonal measurements across nine sites in South and Lower South SF Bay, the two sub-embayments with the highest rates of area-normalized N loading, to determine the rates and potential drivers of denitrification and dissimilatory nitrate reduction to ammonium (DNRA). Denitrification rates averaged 60.6 ± 8.1 µmol m−2 h−1 and were primarily coupled to nitrification. Denitrification rates were positively correlated with DNRA rates and % clay. DNRA rates ranged from 0 to 20 µmol m−2 h−1 and on an annual basis averaged ~ 10% of total benthic nitrate reduction, with a negative correlation to % clay content in the surface sediment. The measured denitrification rates account for the removal of, on average, 14% of N loaded annually to South SF Bay, leaving a sizeable portion for alternate fates (e.g., recycling, export, or burial) and potential for substantial temporal and spatial variability (1–79%). This identifies the relative importance of sediment denitrification in ecosystems characterized by high nutrients and low productivity.

Influence of Potting Radius on the Structural Performance and Failure Mechanism of Inserts in Sandwich Structures

In this study, the mechanical performance and failure modes of cold-potted inserts within sandwich structures were examined, focusing on the influence of the potting radius, while maintaining constant insert radius and specimen characteristics. In this research, destructive testing was used to evaluate the pull out, load-carrying capacity, and failure mechanisms of the inserts. The methods of stiffness degradation and acoustic emissions (AE) were employed for structural health monitoring to capture real-time data on failure progression, including core buckling, core rupture, and skin delamination. The results indicated that increasing the potting radius significantly altered the failure modes and critical failure load of the insert system. A critical potting radius was identified where maximum stiffness was achieved. Beyond this point, insert fracture became the dominant failure mode, with minimal damage to the surrounding core and CFRP skins. Larger potting radii also led to reduced displacement at failure, increased ultimate loads, and elevated stiffness, which were maintained until sudden structural failure. Through detailed isolation and observation of each failure event and with the use of AE data, precise identification of system damage in real time was allowed, offering insights into the progression and causes of failure.

Effectiveness of Friction Damper Configurations on the Behaviour of Bundled Tube High-Rise Building System for Lateral Loads

Effectiveness of Friction Damper Configurations on the Behaviour of Bundled Tube High-Rise Building System for Lateral Loads

Novel robust control with disturbance rejection for permanent magnet synchronous motors and experimental validation.

A novel robust control strategy is proposed in this work to address the dynamic control problem of permanent magnet synchronous motors (PMSM) position tracking and lessen the effect of system parameter and load fluctuations on the dynamic performance of PMSM. The tracking performance is improved by a robust control element built with the Lyapunov method to reduce the impact of uncertain factors such as parameter uncertainty, nonlinear friction, and external interference; the nominal control element is stabilized by the dynamics model. The uniformly bounded and uniformly final bounded systems are proven, and the associated conclusions are provided using the Lyapunov minimax approach. In this work, modeling and experimental investigation are conducted using the cSPACE fast controller, based on the permanent magnet synchronous motor test platform. The results of the testing and simulation show that the developed controller can effectively regulate the permanent magnet synchronous motor and achieve more accurate position tracking even in the face of ambiguity.

Ordered mesoporous silica and carbon as controlled release systems for cephalexin: Influence of surface modification and porosity

This study compares two in vitro loading and release systems for the antibiotic cephalexin (CFX), based on ordered mesoporous silica (SBA-15) and carbon (CMK-5) materials, both pure and modified with 3-aminopropyltriethoxysilane. Drug loading was performed using the adsorption method under constant conditions (pH: 6, T: 30°C, and t: 8 h), and the release mechanisms were investigated at gastric and intestinal pH to understand the phenomena involved in the oral delivery of CFX studied. The results revealed a higher adsorption capacity of CMK-5 due to its microporosity and π-π stacking interactions compared to SBA-15. Furthermore, the presence of functional groups prevented the formation of crystalline phases by adsorption on the external surface. A reduction in the release rate of CFX was observed with both carriers, governed by a Fickian diffusion mechanism. Notably, CMK-5 exhibited a higher release rate at gastric pH compared to SBA-15, while the opposite was true at intestinal pH. These findings provide deeper insights into the behavior of carriers with different chemical compositions in antibiotic release, suggesting their potential as an alternative to address issues associated with the dosing frequency of these drugs.

Modeling method for simulating electrical load system of civil aircraft based on CPU-FPGA

Modeling method for simulating electrical load system of civil aircraft based on CPU-FPGA

Research and application of cargo hold management control technology in civil aviation cargo loading system

Research and application of cargo hold management control technology in civil aviation cargo loading system

Analyzing market plans for enhanced energy hub efficiency: strategies for integrating multiple energy sources and collaboration

ABSTRACT In this study, we introduce the Archimedes optimization algorithm as a key component of our methodology. The Archimedes algorithm, renowned for its robustness and efficiency, is specifically tailored to handle complex optimization problems encountered in energy management systems. By leveraging its unique capabilities, we ensure precise solutions and rapid convergence even under challenging solution conditions characterized by uncertain energy demand forecasts. The proposed algorithm operates by iteratively refining solutions based on probabilistic load predictions and system constraints. It employs sophisticated optimization techniques to navigate the multi-dimensional solution space efficiently, thereby identifying optimal strategies for energy resource allocation within EHs. By incorporating the Archimedes algorithm into our framework, we can effectively capture the dynamic interactions between various energy carriers and adapt to changing market conditions in real-time. Furthermore, the Archimedes algorithm’s ability to provide near-optimal solutions without the need for exhaustive computational resources makes it particularly well-suited for practical implementation in energy management systems. Its efficiency ensures that decision-makers can obtain actionable insights and make informed decisions quickly, thereby enhancing the operational efficiency and economic viability of EHs. The proposed optimization algorithm outperforms alternatives like Archimedes optimization algorithm (APO) and genetic algorithm (GA). On average, it requires 25% fewer iterations for convergence. Moreover, it achieves a 90% convergence rate within just 50 iterations, compared to 70 iterations for APO and 60 iterations for GA, based on 30 distinct runs.

Fatigue Experiment and Failure Mechanism Analysis of Aircraft Titanium Alloy Wing-Body Connection Joint.

Taking the titanium alloy wing-body connection joint at the rear beam of a certain type of aircraft as the research object, this study analyzed the failure mechanism and verified the structural safety of the wing-body connection joint under actual flight loads. Firstly, this study verified the validity of the loading system and the measuring system in the test system through the pre-test, and the repeatability of the test was analyzed for error to ensure the accuracy of the experimental data. Then, the test piece was subjected to 400,000 random load tests of flight takeoffs and landings, 100,000 Class A load tests, and ground-air-ground load tests, and the test piece fractured under the ground-air-ground load tests. Lastly, the mechanism analysis and structural safety verification of the fatigue fracture of the joints were carried out by using a stereo microscope and scanning electron microscope. The results show that fretting fatigue is the main driving force for crack initiation, and the crack shows significant fatigue damage characteristics in the stable growth stage and follows Paris' law. Entering the final fracture region, the joint mainly experienced ductile fracture, with typical plastic deformation features such as dimples and tear ridges before fracture. The fatigue crack growth behavior of the joint was quantitatively analyzed using Paris' law, and the calculated crack growth period life was 207,374 loadings. This result proves that the crack initiation life accounts for 95.19% of the full life cycle, which is much higher than the design requirement of 400,000 landings and takeoffs, indicating that the structural design of this test piece is on the conservative side and meets the requirements of aircraft operational safety. This research is of great significance in improving the safety and reliability of aircraft structures.