Analysis Of Load Characteristics Research Articles

Modeling EV dynamic wireless charging loads and constructing risk constrained operating strategy for associated distribution systems

Dynamic wireless charging (DWC) is an emerging technology that enables the charging of electric vehicles (EVs) while they are in motion. However, previous load modeling methods have not thoroughly explored the detailed analysis of DWC load characteristics. Existing research only considers the single-node supply mode for dynamic wireless charging roads (DWCRs), and the assessment of operational risks arising from the uncertain DWC loads has not been addressed. This paper begins by conducting an equivalent circuit analysis of a typical EV DWC system with multiple segmented coils. We present a more accurate trapezoidal power model for a single EV. Subsequently, we model the aggregated EV DWC load, accounting for traffic flow and headway using Poisson and negative exponential distribution functions, respectively. In the operation process, we consider a multi-node supply mode for DWCRs. To address the inaccuracy of long-term predictions, we propose a rolling optimization model to coordinate DWC and renewables with heterogeneous uncertainties by introducing a risk metric to manage potential uncertain risks. The proposed optimization model is transformed into a mixed-integer second-order cone programming (MISOCP) problem after convex relaxation. Finally, we conduct case studies to validate the proposed methods.

Partial abrasion modeling and variable load characteristics analysis for high-speed load sensing electro-hydrostatic actuator pump of aircraft

The load-sensing electro-hydrostatic actuator (LS-EHA) allows to reduce the thermal output and enhance the dynamic characteristics of the more electric aircraft (MEA). In addition, the forecasting of the LS-EHA is crucial for its efficient functioning. This study proposes a novel model for the analysis of overturning and wear characterization of the slipper, while focusing on the partial abrasion. The transient thermoelastic hydrodynamic (TEHD) lubricating analysis of the slipper pair is solved by an analytical model along with the finite difference method. In the proposed partial abrasion model, the non-uniformity of the oil film thickness and the partial abrasion contour for the slipper bottom surface are considered through the discrete friction area approach in order to reach a higher precision. Afterward, the overturning behavior characteristics of the slipper and the variation law in its overturning behavior under different rotation speeds, load delivery pressures, and swashplate angles are analyzed. The obtained results demonstrate that the lubricating oil film field is unevenly distributed, and the overturning behavior of the slipper has certain variable load characteristics. Finally, the effectiveness and precision of the proposed partial abrasion model are validated through comparative simulation experiments and analysis.

Comparative analysis of dynamic load characteristics of artillery steering gear based on different MBD methods

The multi-body dynamics analysis model of the steering gear of a certain type of artillery was established. The dynamic load characteristics of the output gear of the steering gear motor and its driven gear under the given speed and load conditions were calculated based on the three different MBD analysis methods, such as the speed, meshing force, and contact stress. Through the comparative analysis, it was concluded that the calculation results of rigid-flexible coupling analysis were closer to the theoretical value and the fluctuation range was smaller, which provides reference and basis for the prediction of gear fatigue life and the optimization design under dynamic load conditions.

Analysis of load characteristics of wind turbine blade root bolts under loosened and fractured conditions

Analysis of load characteristics of wind turbine blade root bolts under loosened and fractured conditions

Low carbon and economic optimal operation of electricity-gas integrated energy system considering demand response

Integrated Energy System is an important direction for the transformation of the power industry. IES can give full play to the complementary role of multiple energy sources and serve to achieve the industry's energy saving and emission reduction goals. Firstly, this paper establishes a P2G refined operation model considering two stages of hydrogen production from electrolytic water and hydrogen methanation. Secondly, based on the analysis of the IES load characteristics, the multi-energy loads are divided into longitudinal demand responses where the same energy type can be transferred and reduced in time, and horizontal demand responses where different energy types can be substituted for each other, and the corresponding mathematical models are established. Finally, the reward and penalty ladder carbon trading mechanism are used to quantify the carbon trading cost, and the IES low-carbon economic optimization model integrating the Power-to-gas refinement model and demand response is constructed. The model was subjected to second-order cone programming relaxation and incremental segmented linearization methods before being solved using the CPLEX commercial solver. Simulation analyses were performed in an IES consisting of an IEEE 33-node distribution network and a 24-node gas distribution network. The results show that considering demand response can fully exploit the flexible coordination performance of the load side, resulting in a 12.6% reduction in total system cost and a 38.8% reduction in carbon emissions.

Optimal operation of electric–freshwater energy system considering load regulation strategy of individual hydrogen electrolyzer

AbstractIn view of the existing literature, only the optimization operation of hydrogen energy–wind/light new energy is considered, and the research problems such as comprehensive utilization of water resources and load control strategies are ignored. Based on the analysis of load characteristics of offshore wind power, this paper has established an optimal operation model of power‐fresh water energy system based on “wind‐hydrogen‐water‐electricity” interaction. Meanwhile, an electrolytic hydrogen individual load control strategy is proposed to match wind power fluctuations from the perspective of internal load regulation of electrolytic hydrogen system. From the economic characteristics, operation characteristics, accommodation situation and other simulation analysis, it can reduce the total operating cost by about 3.1%, improve the utilization rate of electrolytic cell capacity, and meet the water demand of coastal users. It shows that the individual control strategy and optimal operation model have advantages, which is of great significance for realizing low‐carbon, safe, and economical operation of power grid in the future.

Analysis of Cooling Load Characteristics in Chinese Residential Districts for HVAC System Design

Energy consumption in residential buildings accounts for a large portion of global energy use. Understanding residential building load characteristics is important in both the design and technical suitability analysis of residential air conditioning systems in terms of energy efficiency and carbon reduction. However, most current research mainly focuses on the load characteristics of individual buildings and not on the variation in load characteristics of building aggregation. In addition, the load characteristics of building aggregations vary with the building scale; however, most studies have compared those of buildings under a certain scale, and the change with the increase in building scale is still unclear. The main purpose of this study is to explore load characteristic differences among residential buildings of different scales and the impacts of those differences on HVAC system design. Based on the monitoring data collected in a residential district in Zhengzhou, China, we analyzed the load characteristics among different households and combinations of different numbers of households from the variation in peak load, total consumption and load distribution, as well as the daily load volatility. We indicate that the load characteristics of heating, ventilation and air conditioning systems of different scales should be considered in the design and operation stage.

Load characteristics analysis of the water source heat pump heating system using data center waste heat

The number and scale of data centers (DCs) in China are constantly expanding with the advancement of networking and informatization. A large amount of waste heat is dissipated at its end. If this waste heat can be recovered, then achieving carbon neutrality in DCs can be effectively accelerated. At present, water source heat pump (WSHP) are widely used in air-cooled and liquid-cooled DCs of different sizes for waste heat recovery. This study analyzes the equipment type and heating capacity of different brands of WSHP units. Three WSHP heating systems are proposed according to the different locations of waste heat enhancement (SE, TDE, UE). The coupling and matching relationship between user-side heat load demand, DC waste heat load, and energy efficiency of WSHP units under different systems is also investigated. Moreover, the law of energy consumption and energy efficiency changes is analyzed. Thus, this study provides a reference for the DC waste heat recovery system design and equipment development. The results show that the coupling matching relationship between user-side heat load demand, DC waste heat load, and heating COP of WSHP units is Q.N/Q.S=COP′/COP′-1=φ, where φ ranges from 1.1962 to 1.3642. The heating COP of the SE system is the greatest when user-side heat load demand is between 0 and 120 kW. The heating COP of the TDE system is the highest when the user-side heat load demand is between 1750 and 70000 kW. Furthermore, the heating COP of the three WSHP heating system types is related to unit brand when user-side heat load demand is between 120 and 1750 kW.

Active distribution network type identification method of high proportion new energy power system based on source-load matching

A large number of distributed new energy and flexible loads are connected to the distribution network, resulting in increasingly complex source load characteristics and supply and demand situations. The analysis of source load characteristics and accurate division of network types are the basis for the accurate planning of active distribution networks. Here, we report an active distribution network type identification method based on source-load matching. Firstly, the typical daily output scenarios of DG are extracted by clustering method, and the generalized load curve model is solved by the optimization algorithm to obtain the source load operation data; Secondly, calculate the source-load matching indicators (including matching performance, matching degree, and matching rate) according to the source load data of each region, and identify the distribution network type according to the range of the index values; Finally, several indicators are introduced to quantify the characteristics of different types of distribution networks. A case study of a power supply grid in Zhejiang Province is used to verify the practicability of the proposed method for active distribution network planning.

Electricity Correlation Evaluation Based on Improved Logistic Algorithm Integrating Periodic Characteristics of Load and Temperature

The power system (abbreviated as PS for convenience) is one of the indispensable infrastructures in modern society, and its stable operation is crucial for ensuring the normal operation of the national economy and society. With the continuous expansion and complexity of the power grid, power correlation analysis has become increasingly important in the operation, planning, and management of the power system. Temperature is one of the main factors affecting power load (abbreviated as PL for convenience), and how to integrate the periodic characteristics of temperature with load analysis has become a top priority. This article improved the logistic algorithm and applied it to the power correlation analysis of combined load and temperature periodic characteristics and collected four seasonal PL parameters and temperature parameters from January to December 2022. The study analyzed the correlation between PL and temperature periodic characteristics, and also compared the accuracy of PS correlation analysis using the logistic algorithm and improved logistic algorithm. According to the experimental results, it could be concluded that at 1 and 2 o’clock on 1 January 2022, the temperature was at the lowest, both of which were −3 °C, while the PS load was 1000 MW and 1100 MW, respectively. It could be seen that in winter, as the temperature was lower the PL increased. In July 2022, the load and temperature of the PS were continuously increasing, reaching their maximum at 10 o’clock and it could be observed that as the temperature increased, the PL also increased. This was because both low and high temperatures increased the operation of the power equipment, thereby increasing the PL. It was also confirmed that fusing multiple features and adopting an improved logistic algorithm could improve the accuracy of the prediction results. The improved logistic algorithm could be applied to related fields such as PL forecasting and provide a scientific decision-making basis for the power industry. This could also provide a reference for data analysis and prediction in other fields.

AttG-BDGNets: Attention-Guided Bidirectional Dynamic Graph IndRNN for Non-Intrusive Load Monitoring

Most current non-intrusive load monitoring methods focus on traditional load characteristic analysis and algorithm optimization, lack knowledge of users’ electricity consumption behavior habits, and have poor accuracy. We propose a novel attention-guided bidirectional dynamic graph IndRNN approach. The method first extends sequence or multidimensional data to a topological graph structure. It effectively utilizes the global context by following an adaptive graph topology derived from each set of data content. Then, the bidirectional Graph IndRNN network (Graph IndRNN) encodes the aggregated signals into different graph nodes, which use node information transfer and aggregation based on the entropy measure, power attribute characteristics, and the time-related structural characteristics of the corresponding device signals. The function dynamically incorporates local and global contextual interactions from positive and negative directions to learn the neighboring node information for non-intrusive load decomposition. In addition, using the sequential attention mechanism as a guide while eliminating redundant information facilitates flexible reasoning and establishes good vertex relationships. Finally, we conducted experimental evaluations on multiple open source data, proving that the method has good robustness and accuracy.

Analysis on the Current Energy Consumption of Heating In Rural Toilets in Tibet

In order to grasp the basic sanitation facilities, toilet renovation planning and progress, residents' toilet habits and willingness to renovate, and the maintenance status of renovated toilets in townships and rural areas of Tibet, and to understand the basic situation and toilet renovation planning of public toilets in townships and rural areas. This article selects independent public toilets in agricultural and pastoral areas of Tibet as the research object. In response to the problems of low indoor temperature and high heat consumption in township toilets, the construction and heating status of township toilets were obtained through on-site research. The heating characteristics of township toilet buildings were summarized, and typical buildings were selected for load characteristics analysis, providing a preliminary basis for the design of solar heating schemes in the future.

Analysis of the Dynamic Load Characteristics of Double-Top-Beam Supports with Gaps

Analysis of the Dynamic Load Characteristics of Double-Top-Beam Supports with Gaps

Multi-twinned deformation and fracture characteristics of directional solidified Ti-45.5Al–5Nb-0.5Ta alloys during high-temperature rotary-bending fatigue process

Ф 16.5 mm directional solidified Ti-45.5Al–5Nb-0.5Ta alloy was obtained through electromagnetic confinement methods. Relative rotary-bending fatigue experiment with different loads were also performed at 760 °C. The rotary-bending fatigue limit of the alloy at 760 °C is 269 MPa, and the fracture mode is a composite fracture mode of cleavage fracture and lamellar tearing. Based on the combination of EBSD and PED technology, crack bridging characteristics and microstructure deformation during the rotary-bending fatigue process were analyzed. Crack bridging is induced by banded dislocation pileups at the tips of adjacent cracks, which releases the stress concentration in the local microstructure and enhances the scale of crack extension. Moreover, the orientation of γ phase is deflected by 60°–70° during the crack bridging process. Furthermore, combined with the analysis of the mechanical load characteristics during the rotary-bending fatigue process, the initiation and evolution mechanism of the multi-twinned deformation and its influence on the deformation capacity of the alloy were obtained. The initiation of one type γ-twins is the stacking fault caused by dislocation slip from the α/γ phase boundary, and the initiation of the other γ-twins is atomic plane slips caused by twin misalignments or dislocation slips.

Analysis of Dynamic Load Characteristics of Accelerated Pavement Testing Equipment Based on Virtual Prototype Model

The purpose of this paper is to study the actual dynamic load characteristics of a full-scale Accelerated Pavement Test (APT) device called Natural Environment-Automatically Loaded Track (NE-ALT) during its operation. The NEALT uses hydraulic and support reaction forces to apply axle loads, which are somewhat different from real trucks. Therefore, in order to ensure the accuracy of the loading parameters of the device, it is necessary to analyze the dynamic load characteristics of the device during operation. In this paper, a virtual prototype model of the device was established, and the important parameters, including vehicle speed and axle load, were set. The dynamic axle load, dynamic load coefficient, and influential factors of the NE-ALT were analyzed using the model at different speeds, hydraulic pressures, and road roughness. The results have shown that the dynamic axle load accuracy was most affected by speed, followed by road roughness, and then hydraulic cylinder pressure. Compared with the real truck, its dynamic load stability was better than the real truck due to the restriction of the guide rail in the acceleration loading system and the method of hydraulic loading, and the larger the load, the more stable the load, which was different from the real truck. Therefore, in the design of accelerated pavement loading experiments, the dynamic axle load characteristics of equipment need to be considered. The results of this study can provide guidance for the further improvement and application of the NE-ALT.

On the Springback and Load in Three-Point Air Bending of the AW-2024 Aluminium Alloy Sheet with AW-1050A Aluminium Cladding.

This article presents the results of an analysis of the bending load characteristics and the springback phenomenon occurring during three-point bending of 1.0 and 2.0 mm thick AW-2024 aluminium alloy sheets with rolled AW-1050A cladding. A new proprietary equation was proposed for determining the bending angle as a function of deflection, which takes into account the influence of the tool radius and the sheet thickness. The experimentally determined springback and bending load characteristics were compared with the results of numerical modelling using different models: Model I, a 2D model for a plane deformation state, disregarding the material properties of the clad layers; Model II, a 2D model for a plane deformation state, taking into account the material properties of the cladding layers; Model III, a 3D shell model with the Huber-von Mises isotropic plasticity condition; Model IV, a 3D shell model with the Hill anisotropic plasticity condition; and Model V, a 3D shell model with the Barlat anisotropic plasticity condition. The effectiveness of these five tested FEM models in predicting the bending load and springback characteristics was demonstrated. Model II was the most effective in predicting bending load, while Model III was the most effective in predicting the amount of springback after bending.

Peak Load Shifting Control for a Rural Home Hotel Cluster Based on Power Load Characteristic Analysis

The large-scale rural home hotel clusters have brought huge pressure to the rural power grid. However, the load of rural home hotels not only has the inherent characteristics of rural residential buildings but is also greatly impacted by the occupancy rate, which is very different from conventional buildings. Therefore, the existing peak shifting strategies are difficult to apply to rural home hotels. In view of the above problems, this study took a typical visitor village in Zhejiang Province as the research object, which had more than 470 rural home hotels. First, through a basic information survey and power load data collection, the characteristics of its power load for heating, cooling and transition months were studied, and a “No Visitors Day” model was proposed, which was split to obtain the seasonal load curve for air conditioning. Then, combined with the characteristics of the air conditioning power load and the natural conditions of the rural house, a cluster control peak-load-shifting system using phase change energy storage was proposed, and the system control logic was determined and established. Finally, the collected power load data was brought into the model for actual case analysis to verify its feasibility and the effect of peak-load shifting. The results showed that due to the influence of the number of tourists, the electricity loads on weekends and holidays were higher, especially the electricity load of air conditioning equipment in the heating and cooling seasons. An actual case was simulated to verify the peak-shifting effect of the proposed regulation strategy; it was found that the maximum peak load of the cluster was reduced by 61.6%, and the peak–valley difference was 28.6% of that before peak shifting.

Load characteristics analysis of tractor drivetrain under field plowing operation considering tire-soil interaction

The drivetrain of a tractor is prone to fatigue failure under heavy load plowing operations. The load variation of its transmission shafting is affected by the "machine-soil" interaction environment, especially the tire-soil interaction. Therefore, a load transfer model of a tractor plowing operation composed of a drivetrain model, tire-soil interaction model, and tractor dynamics model was established, to analyze the load characteristics of the transmission shafting. For verifying the proposed model, the field plowing process was carried out experimentally. The driving wheels and shafting were discussed as influenced by the slip rate variation in the tire-soil interaction model. The fitting distribution characteristics of cycle average and range of transmission shafting in the rain-flow domain were obtained. The results showed that the established model can accurately simulate the speed and dynamic load characteristics of the tractor plowing operation. The driving wheel loads increased with the increase of slip rate except for the motion resistance. When the slip rate exceeded 25 %, loads of the transmission shafts changed steadily. The reliability of fit R2 of the statistical distribution for transmission shafting load was greater than 0.94. The mean and variance of rear-drive half shaft torque were the largest, where fatigue failure was more likely to occur. The above theoretical model and results provide practical guidance for structural optimization design, fatigue durability analysis and reliability loading test of the tractor drivetrain.

Analysis of Power Load Characteristics Based on Adaptive Ensemble Clustering Algorithm

With the growing number of power users and more flexible power consumption, how to cluster the power load curves efficiently becomes particularly important. In order to improve the accuracy, effectiveness and rapidity of load clustering, an adaptive integrated fuzzy clustering algorithm was proposed in this paper. Firstly, the initial clustering centroids were obtained by the improved DPC algorithm; then, under the dual guarantee of Euclidean distance and membership, FCM algorithm was used to cluster load curves; finally, the optimal number of clusters was obtained by the improved adaptive method in the iterative process; thus, the autonomous and accurate clustering of power load curve was realized. The proposed algorithm, DPC algorithm and FCM algorithm were applied to the load clustering experiment of power system respectively. The comparative analysis shows that this algorithm is effective and superior for load curve clustering.

Design and application of new power load management system

In order to improve the load management ability of the new power system, this paper proposes a design scheme of the new power load management system. The design scheme is based on the cloud platform and adopts the micro service and micro application architecture to build applications such as load control customer management, equipment file management, load monitoring, load characteristic analysis, load control scheme formulation, load regulation and implementation, load implementation monitoring, implementation effect analysis, operation management, power safety, early warning monitoring, command and drill, and realize the real-time monitoring and accurate control of load resources on the customer side. The practical application proves the effectiveness of this scheme in improving the management of customer side load resources.