Modeling load distribution for rural photovoltaic grid areas using image recognition

Expanding photovoltaic(PV)resources in rural-grid areas is an essential means to augment the share of solar energy in the energy landscape,aligning with the“carbon peaking and carbon neutrality”objectives.However,rural power grids often lack digitalization;thus,the load distribution within these areas is not fully known.This hinders the calculation of the available PV capacity and deduction of node voltages.This study proposes a load-distribution modeling approach based on remote-sensing image recognition in pursuit of a scientific framework for developing distributed PV resources in rural grid areas.First,houses in remote-sensing images are accurately recognized using deep-learning techniques based on the YOLOv5 model.The distribution of the houses is then used to estimate the load distribution in the grid area.Next,equally spaced and clustered distribution models are used to adaptively determine the location of the nodes and load power in the distribution lines.Finally,by calculating the connectivity matrix of the nodes,a minimum spanning tree is extracted,the topology of the network is constructed,and the node parameters of the load-distribution model are calculated.The proposed scheme is implemented in a software package and its efficacy is demonstrated by analyzing typical remote-sensing images of rural grid areas.The results underscore the ability of the proposed approach to effectively discern the distribution-line structure and compute the node parameters,thereby offering vital support for determining PV access capability.

Measured dynamic load distribution within the in situ axlebox bearing of high-speed trains under polygonal wheel–rail excitation

The dynamic load distribution within in-service axlebox bearings of high-speed trains is crucial for the fatigue reliability assessment and forward design of axlebox bearings. This paper presents an in situ measurement of the dynamic load distribution in the four rows of two axlebox bearings on a bogie wheelset of a high-speed train under polygonal wheel–rail excitation. The measurement employed an improved strain-based method to measure the dynamic radial load distribution of roller bearings. The four rows of two axlebox bearings on a wheelset exhibited different ranges of loaded zones and different means of distributed loads. Besides, the mean value and standard deviation of measured roller–raceway contact loads showed non-monotonic variations with the frequency of wheel–rail excitation. The fatigue life of the four bearing rows under polygonal wheel–rail excitation was quantitatively predicted by compiling the measured roller–raceway contact load spectra of the most loaded position and considering the load spectra as input.

Load Distribution of Base Stations in User-Centric Heterogeneous UDN

In ultra-dense networks(UDN),multiple association can be regarded as a user-centric pattern in which a user can be served by multiple base stations(BSs).The data rate and quality of service can be improved.However,BSs in user-centric paradigm are required to serve more users due to this multiple association scheme.The improvement of system performance may be limited by the improving load of BSs.In this letter,we develope an analytical framework for the load distribution of BSs in heterogeneous user-centric UDN.Based on open loop power control(OLPC),a user-centric scheme is considered in which the clustered serving BSs can provide given signal to interference plus noise ratio(SINR)for any typical user.As for any BS in different tiers,by leveraging stochastic geometry,we derive the Probability Mass Function(PMF)of the number of the served users,the Cumulative Distribution Function(CDF)of total power consumption,and the CDF bounds of downlink sum data rate.The accuracy of the theoretical analysis is validated by numerical simulations,and the effect the system parameters on the load of BSs is also presented.

Improvement on Conventional Load Distribution Algorithm in Hot Tandem Mills

Load distribution is a key technology in strip hot rolling process, which influences the coil＇s mierostrueture and performance. Currently, Newton-Raphson algorithm is applied to load distribution of hot tandem mills in many hot rolling plants and has some serious defects such as having a strict restriction on initial iterative calculation value and requiring coefficient matrix of nonlinear equations to be nonsingular. To eliminate these defects and improve the online performance of the process control computer, Newton descendent numeric algorithm is introduced to this field to widen the initial value range and a new model named error conversion algorithm is put forth to deal with special conditions when the coefficient matrix is singular. Furthermore, considering the characteristics of load distribution, a condition of strip thickness distribution abnormality and corresponding solutions are provided which ensure that rolling parameters can be calculated normally. Simulation results show that the improved algorithm has overcome the defects of the Newton-Raphson algorithm and is suitable for online application.

Load distribution model and voltage static profile of Smart Grid

Voltage profiles of feeders with the connection of distributed generations(DGs) were investigated.A unified typical load distribution model was established.Based on this model,exact expressions of feeder voltage profile with single and double DGs were derived and used to analyze the impact of DG's location and capacity on the voltage profile quantitatively.Then,a general formula of the voltage profile was derived.The limitation of single DG and necessity of multiple DGs for voltage regulation were also discussed.Through the simulation,voltage profiles of feeders with single and double DGs were compared.The voltage excursion rate is 7.40% for only one DG,while 2.48% and 2.36% for double DGs.It is shown that the feeder voltage can be retained in a more appropriate range with multiple DGs than with only one DG.Distributing the total capacity of DGs is better than concentrating it at one point.

Study on Longitudinal Load Distribution on Gear Tooth

Regularity of longitudinal load distribution on gear tooth when tooth faces are contacted uniformly and when only tooth ends are contacted, and influence on distribution exerted by longitudinal correction and flexible gear structure, are studied in the paper with method of finite element calculation combined with experiment. Research shows that load concentration exists on the conditions of uniform contact or one-end contact, and in the later case the stress nonuniformity factor on root is 1.5 to 2.0 times larger than in the former case. It also verifies that longitudinal correction and increased flexibility of gear structure are effective to improve longitudinal load distribution.

Research on Rolling Load Distribution Method based on Data Mining

A new method of establishing rolling load distribution model was developed by online intelligent information-processing technology for plate rolling. The model combines knowledge model and mathematical model with using knowledge discovery in database （KDD） and data mining （DM） as the start. The online maintenance and optimization of the load model are realized. The effectiveness of this new method was testified by offline simulation and online application.

THEORETICAL INVESTIGATION ON STATE OF LOAD DISTRIBUTION AMONG CONTACT BEARINGS OF DOUBLE CIRCULAR ARC HELICAL GEARS

A dynamic analysis approcach to investigate the state of load distribution among contact bearings of double circular are belical gears is proposed and a computer program is developed for calculating the factor of iced distribution based on the theory of W-N gears. The changing situations of load distribution among contact bearings of the gears influenced by main issues are analyzed by a series of parametric studies.

Theoretical calculation and experimental study on the load distribution coefficient (LDC) of three-ring gear reducer

In this paper, primary manufacturing and assembling errors of three-ring gear reducer （TRGR） are analyzed. TRGR is a new transmission type whose eccentric phase difference between middle ring plate and side ring plates is 120°, Its mass of middle ring plate is equal to that of side ring plate or 180°, and its inass of middle ring plate is twice of that of side ring plate, which affects load distribution between ring plates. The primary manufacturing and assembling errors include eccentric error of eccentric sheath E111, internal gear plate E1 and output external gear E11. A new theoretical method is presented in this paper, which converts load on ring plates into the dedendum bending stress of ring plate to calculate load distribution coefficient （ LDC ）, by means of gap element method （GEM）, one of finite element method （FEM）. The theoretical calculation and experimental study, which measures ring plate dedendum bending stress by means of sticking strain gauges on the dedendum of middle ring plate internal gear and side ring plate internal gears, are presented. The theoretical calculation and comparison with experiment result of LDC are implemented an two kinds of three-ring gear reducers whose eccentric phase difference between eccentric sheaths is 120° and 180°respectively. The research indicates that the result of theoretical calculation is consistent with that of experimental study. That is to say, the theoretical calculation method is feasible.

Stability Analysis for a Planar Parallel Manipulator with the Capability of Self-Coordinating the Load Distribution

Redundantly actuated parallel manipulators have the advantage of enhancing load-carrying capability over their non-redundant ones, however they also cause the problem of uneven load distribution and need a high requirement for the control system. This paper presents a 2-RPR/RP planar redundantly actuated parallel manipulator which can self-coordinate the distribution of external loads. This capability is realized by an appropriate design of the moving platform to make the manipulator stable at equilibrium position. The stability is proved by the theorem of direct Lyapunov method in classical mechanics. The numerical simulations are conducted to validate the stable capability by means of the observation of potential energies and phase planes. This paper offers an alternative way to design a redundantly actuated manipulator with the capability of self-coordinating the load distribution to actuations, such that parts of the controlling work are assigned to the manipulator itself by its own structure and only a little work remains to the control system.

Cooling Load Distribution of Large Space Building

The cooling and heating load distribution of large area air-conditioned room such as “open” offices, shopping malls and waiting rooms is usually assumed to be even in air conditioning system design. However, it is not the case in reality, and a low efficient air conditioning system results from this assumption. A simulation and analysis of the cooling load distribution of an office building in Hong Kong with TRANSYS software is provided in this paper. A typical office is divided into 13 zones for simulation, including external zone, medial zone and internal zone in the north, the south, the east and the west respectively and a central zone, instead of 4 directional zone. The result shows there is much cooling load difference between each zone, and more attention should be paid to uneven indoor cooling and heating load distribution to further guide the design.

Load distribution of involute gears along time-varying contact line

Base on the theory of energy minimization, a numerical algorithm is established to calculate load distribution, and the relationship curve of spur gear load distribution is obtained, and the load distribution ratio changes from 033 to 067 in double contact zone. This theory is adopted to compute the load distribution of helical gear along time-varying contact line, and the load distribution varies with the instantaneous position of the meshing point and the length of contact line, and the maximum value of load appears at the pitch point. Compared with the load distribution results, the helical gear changes more smoothly than spur gear. The load distribution provides a basis for calculate tooth bending deformation and critical stress.

LOAD DISTRIBUTION ON DRUMS OF DOUBLE DRIVE BELT CONVEYOR

The double drum drive is widely used on the mine belt conveyor, which are divided the rigid connected double drums and separately driving double drums according to connected method of two drums. Because of the change of real work condition, the load distribution is changed on the two drive drums, which may produce a slippage between a drum and belt. Slippage may intensify the wear of the drum, and sometimes causing the fire of the belt. This restricts the development toward narrow belt, high velocity and large power of belt conveyor. In this paper, the factors affecting the load distribution of two drums of double drum belt conveyor are systematically analyzed and some computing formulas derived, by these formulas, the actual lcad distribution on the two drums of rigid connected or separately driving belt conveyor can be separately calculated.These formulas also can be as the theory base for adjusting the driving force of two drums.

An Improved Differential Evolution Whale Algorithm for Economic Load Distribution

An improved optimization algorithm combining the differential evolution algorithm and the whale algorithm is proposed for the problem of not being able to get rid of the local optimum in the economic load distribution algorithm. The algorithm adopts a nonlinear convergence strategy, a crossover strategy of differential evolution and the introduction of an elimination mechanism, which balances the global search and local exploitation ability of the algorithm and improves the accuracy of the solved optimal solution. The 13-unit and 40-unit systems are selected for economic load distribution calculation, and the experimental results show that the proposed improved algorithm is superior in distributing the economic load of the power system and can effectively reduce the economic cost.

INFLUENCE OF THREAD PITCH ON LOAD DISTRIBUTION ON THREADED END OF PRESSURE CYLINDER

One of the design methods for closing the end of a pressure cylinder is to screw down a screw plug on the threaded end of the cylinder. In this case, there is the problem of stress concentration in the threaded end of the pressure cylinder. To solve the problem, it is necessary to know accurately the load distribution on the threaded end of the cylinder. To find the load distribution on the threaded end of the pressure cylinder engaged with the screw plug, the following experiments are carried out. Applying the tensile load between the screw plug and the pressure cylinder and regarding the situation above as equivalent to the situation in which the internal pressure is applied, the load distribution is measured with the strain gauge. The influence of thread pitch on the load distribution on the threaded end of the cylinder is presented and an optimum pitch for design is discussed.

Electric Vehicle Charging Capacity of Distribution Network Considering Conventional Load Composition

At present,the large-scale access to electric vehicles(EVs)is exerting considerable pressure on the distribution network.Hence,it is particularly important to analyze the capacity of the distribution network to accommodate EVs.To this end,we propose a method for analyzing the EV capacity of the distribution network by considering the composition of the conventional load.First,the analysis and pretreatment methods for the distribution network architecture and conventional load are proposed.Second,the charging behavior of an EVis simulated by combining the Monte Carlo method and the trip chain theory.After obtaining the temporal and spatial distribution of the EV charging load,themethod of distribution according to the proportion of the same type of conventional load among the nodes is adopted to integrate the EV charging load with the conventional load of the distribution network.By adjusting the EV ownership,the EV capacity in the distribution network is analyzed and solved on the basis of the following indices:node voltage,branch current,and transformer capacity.Finally,by considering the 10-kV distribution network in some areas of an actual city as an example,we show that the proposed analysis method can obtain a more reasonable number of EVs to be accommodated in the distribution network.

Load distribution strategy for multi-lift system with helicopters based on power consumption and robust adaptive game control

It is of great significance to reasonably distribute the slung load to each helicopter while considering difference in power consumption,relative position and interaction comprehensively.Therefore,the load distribution strategy based on power consumption and robust adaptive game control is proposed in this paper.The study is on a"2-lead"multi-lift system of four tandem heli-copters carrying a load cooperatively.First,based on the hierarchical control,the load distribution problem is divided into two parts:the calculation of expected cable force and the calculation of the anti-disturbance cable force.Then,aimed at minimizing the maximum equivalent power of heli-copter,an optimization problem is set up to calculate the expected cable force.Specially,the agent power model is trained by BP neural network,the safe distance constraint between helicopters is set to 2.5 rotor diameters to reduce aerodynamic interference,and the helicopters with different perfor-mance can be considered by introducing the equivalent power factor into the objective function.Next,considering the difference and interaction between helicopters,the robust adaptive differen-tial game control is proposed to calculate the anti-disturbance cable force.Particularly,to solve the coupled Hamiltonian equations,an adaptive solving method for value function is proposed,and its stability is proved in the sense of Lyapunov.The simulation results indicate that the proposed load distribution method based on power consumption is applicable to the entire flight trajectory even there are differences between helicopters.The game control can consider interaction between heli-copters,can deal with different objective functions,and has strong robustness and small steady-state error.Based on the entire strategy,the cable force can be reasonably allocated so as to resist disturbance and improve the flight performance of the whole system.

A novel approach to the dynamic response analysis of Euler-Bernoulli beams resting on a Winkler soil model and subjected to impact loads

This work presents a novel approach to the dynamic response analysis of a Euler-Bernoulli beam resting on a Winkler soil model and subjected to an impact loading.The approach considers that damping has much less importance in controlling the maximum response to impulsive loadings because the maximum response is reached in a very short time,before the damping forces can dissipate a significant portion of the energy input into the system.The development of two sine series solutions,relating to different types of impulsive loadings,one involving a single concentrated force and the other a distributed line load,are presented.This study revealed that when a simply supported Euler-Bernoulli beam,resting on a Winkler soil model,is subject to an impact load,the resulting vertical displacements,bending moments and shear forces produced along the span of the beam are considerably affected.In particular,the quantification of this effect is best observed,relative to the corresponding static solution,via an amplification factor.The computed impact amplification factors,for the sub-grade moduli used in this study,were in magnitude greater than 2,thus confirming the multiple-degree-of-freedom nature of the problem.

Multi-Objective Load Distribution Optimization for Hot Strip Mills

Load distribution is a key technology in hot strip rolling process, which directly influences strip product quality. A multi-objective load distribution model, which takes into account the rolling force margin balance, roll wear ratio and strip shape control, is presented. To avoid the selection of weight coefficients encountered in single objective optimization, a multi-objective differential evolutionary algorithm, called MaximinDE, is proposed to solve this model. The experimental results based on practical production data indicate that MaximinDE can obtain a good pareto-optimal solution set, which consists of a series of alternative solutions to load distribution. Decision-makers can select a trade-off solution from the pareto-optimal solution set based on their experience or the importance of ob- iectives. In comparison with the empirical load distribution solution, the trade-off solution can achieve a better per- formance, which demonstrates the effectiveness of the multi-objective load distribution optimization. Moreover, the conflicting relationship among different objectives can be also found, which is another advantage of multi-objective load distribution optimization.

Generalized Shape and Gauge Decoupling Load Distribution Optimization Based on IGA for Tandem Cold Mill

Load distribution is the foundation of shape control and gauge control, in which it is necessary to take into account the shape control ability of TCM （tandem cold mill） for strip shape and gauge quality. First, the objective function of generalized shape and gauge decoupling load distribution optimization was established, which considered the rolling force characteristics of the first and last stands in TCM, the relative power, and the TCM shape control ability. Then, IGA （immune genetic algorithm） was used to accomplish this multi-objective load distribution optimization for TCM. After simulation and comparison with the practical load distribution strategy in one tandem cold mill, general- ized shape and gauge decoupling load distribution optimization on the basis of IGA approved good ability of optimizing shape control and gauge control simultaneously.