Net Loads Research Articles

Net section fracture of S700 high strength steel staggered bolted connections

The present paper describes a thorough experimental and numerical investigation into the net section failure and load-carrying capacities of S700 high strength steel staggered bolted connections subjected to tension. The experimental programme was carried out on fifteen S700 high strength steel double-shear staggered bolted connection specimens. The connection test setup and procedures as well as the key experimental results were reported in detail. Following the experimental programme, a numerical modelling programme was perform, where finite element models were initially developed to replicate the tests and then employed to conduct parametric studies. On the basis of the obtained test and numerical data, the effect of the transverse and staggered pitches on the net section failure loads and modes were studied and the accuracy of the relevant codified design rules was assessed. Generally, the American specification yields the highest level of design accuracy, though with some unsafe predicted resistances, while the European code and Australian standard lead to more conservative design resistances but all the design resistances are still relatively accurate and safe. Moreover, all the three design codes were shown to result in more accurate failure load predictions for 2-bolt staggered connections than for 3-bolt staggered connections.

The Role of Vertebral Porosity and Implant Loading Mode on Bone-Tissue Stress in the Human Vertebral Body Following Lumbar Total Disc Arthroplasty.

Micro-computed tomography- (micro-CT-) based finite element analysis of cadaveric human lumbar vertebrae virtually implanted with total disc arthroplasty (TDA) implants. (1) Assess the relationship between vertebral porosity and maximum levels of bone-tissue stress following TDA; (2) determine whether the implant's loading mode (axial compression vs. sagittal bending) alters the relationship between vertebral porosity and bone-tissue stress. Implant subsidence may be related to the bone biomechanics in the underlying vertebral body, which are poorly understood. For example, it remains unclear how the stresses that develop in the supporting bone tissue depend on the implant's loading mode or on typical inter-individual variations in vertebral morphology. Data from micro-CT scans from 12 human lumbar vertebrae (8 males, 4 females; 51-89 years of age; bone volume fraction [BV/TV] = 0.060-0.145) were used to construct high-resolution finite element models (37 μm element edge length) comprising disc-vertebra-implant motion segments. Implants were loaded to 800 N of force in axial compression, flexion-, and extension-induced impingement. For comparison, the same net loads were applied via an intact disc without an implant. Linear regression was used to assess the relationship between BV/TV, loading mode, and the specimen-specific change in stress caused by implantation. The increase in maximum bone-tissue stress caused by implantation depended on loading mode (P < 0.001), increasing more in bending-induced impingement than axial compression (for the same applied force). The change in maximum stress was significantly associated with BV/TV (P = 0.002): higher porosity vertebrae experienced a disproportionate increase in stress compared with lower porosity vertebrae. There was a significant interaction between loading mode and BV/TV (P = 0.002), indicating that loading mode altered the relationship between BV/TV and the change in maximum bone-tissue stress. Typically-sized TDA implants disproportionately increase the bone-tissue stress in more porous vertebrae; this affect is accentuated when the implant impinges in sagittal bending.Level of Evidence: N/A.

A Reliable U-trough Runoff Collection Method for Quantifying the Migration Loads of Nutrients at Different Soil Layers under Natural Rainfall

Long-term quantification of the migration loads of subsurface runoff (SSR) and its collateral soil nutrients among different soil layers are still restricted by the runoff collection method. This study tested the reliability of the U-trough collection methods (UCM), compared with the seepage plate collection method (SPM), in monitoring the runoff, sediment and nutrient migration loads from different soil layers (L1: 0–20 cm depth; L2: 20–40 cm depth; L3: 40–60 cm depth) for two calendar years under natural rainfall events. The results suggested that the U-trough could collect nearly 10 times the SSR sample volume of the seepage plate and keep the sampling probability more than 95% at each soil layer. The annual SSR flux from L1 to L3 was 403.4 mm, 271.9 mm, and 237.4 mm under the UCM, 14.35%, 10.56%, and 8.41% lower than those under the SPM, respectively. The annual net migration loads of sediment, TN, and TP from the L1 layer under the UCM were 49.562 t/km2, 19.113 t/km2 and 0.291 t/km2, and 86.62%, 41.21% and 81.78% of them were intercepted by the subsoil layers (L2 and L3), respectively. While their migration loads under the SPM were 48.708 t/km2, 22.342 t/km2 and 0.291 t/km2, and 88.24%, 53.06% and 80.42% of them were intercepted, respectively. Under both methods, the average leached total n (TN), total p (TP) concentrations per rainfall event and their annual migrated loads at each soil layer showed no significant difference. In conclusion, the UCM was a reliable quantitative method for subsurface runoff, sediment, and soil nutrient migration loads from diverse soil layers of purple soil sloping cultivated lands. Further studies are needed to testify the availability in other lands.

Testing and design of stainless steel staggered bolted connections

The present paper reports a thorough experimental investigation into the net section failure behaviour and capacity of stainless steel staggered bolted connections in tension. The testing programme was carried out on 31 stainless steel staggered bolted connection specimens, with 18 made of austenitic stainless steel (grade EN 1.4301), 7 made of duplex stainless steel (grade EN 1.4462) and 6 made of ferritic stainless steel (grade EN 1.4016). The geometric parameters, including the transverse and staggered pitches, and the staggered bolt hole patterns of the connection specimens, were varied. The test setup and procedures, as well as the key experimentally observed results, including the net section failure modes and loads, are reported in detail. The experimentally obtained net section failure loads and modes are analysed and discussed, and then utilised to assess the accuracy of the established design rules for stainless steel staggered bolted connections, given in the European, American and Australian/New Zealand standards. All three examined standards consider (i) net section fracture and (ii) gross section yielding in the design of stainless steel staggered bolted connections, and specify that the design failure load shall be taken as the minimum value calculated from all potential failure modes. It was found that the current design standards lead to overly conservative and scattered failure load predictions as well as inaccurate failure mode predictions. A new design approach based on the continuous strength method (CSM) is proposed, and shown to result in substantially improved predictions of both failure loads and failure modes.

Disentangling the Impact of Catchment Heterogeneity on Nitrate Export Dynamics From Event to Long‐Term Time Scales

AbstractDefining effective measures to reduce nitrate pollution in heterogeneous mesoscale catchments remains challenging when based on concentration measurements at the outlet only. One reason for this is our limited understanding of the subcatchment contributions to nitrate export and their importance at different time scales. While upstream subcatchments often disproportionally contribute to runoff generation and in turn to nutrient export, agricultural areas (which are typically found in downstream lowlands) are known to be a major source of nitrate pollution. To examine the interplay of different subcatchments, we analyzed seasonal long‐term trends and event dynamics of nitrate concentrations, loads, and the concentration–discharge relationship in three nested catchments within the Selke catchment (456 km2), Germany. The upstream subcatchments (40.4% of total catchment area, 34.5% of N input) had short transit times and dynamic concentration–discharge relationships with elevated nitrate concentrations during wet seasons and events. Consequently, the upstream subcatchments dominated nitrate export during high flow and disproportionally contributed to overall annual nitrate loads at the outlet (64.2%). The downstream subcatchment was characterized by higher N input, longer transit times, and relatively constant nitrate concentrations between seasons, dominating nitrate export during low‐flow periods. Neglecting the disproportional role of upstream subcatchments for temporally elevated nitrate concentrations and net annual loads can lead to an overestimation of the role of agricultural lowlands. Nonetheless, constantly high concentrations from nitrate legacies pose a long‐term threat to water quality in agricultural lowlands. This knowledge is crucial for an effective and site‐specific water quality management.

Spatiotemporal Behind-the-Meter Load and PV Power Forecasting via Deep Graph Dictionary Learning.

In recent years, with the rapid growth of rooftop photovoltaic (PV) generation in distribution networks, power system operators call for accurate forecasts of the behind-the-meter (BTM) load and PV generation. However, the existing forecasting methodologies are incapable of quantifying such BTM measurements as the smart meters can merely measure the net load time series. Motivated by this challenge, this article presents the spatiotemporal BTM load and PV forecasting (ST-BTMLPVF) problem. The objective is to disaggregate the historical net loads of neighboring residential units into their BTM load and PV generation and forecast the future values of these unobservable time series. To solve ST-BTMLPVF, we model the units as a spatiotemporal graph (ST-graph) where the nodes represent the net load measurements of units and edges reflect the mutual correlation between the units. An ST-graph autoencoder (ST-GAE) is devised to capture the spatiotemporal manifold of the ST-graph, and a novel spatiotemporal graph dictionary learning (STGDL) optimization is proposed to utilize the latent features of the ST-GAE to find the most significant spatiotemporal features of the net load. STGDL utilizes the captured features to estimate the historical BTM load and PV measurements, which are further used by a deep recurrent structure to forecast the future values of BTM load and PV generation at each unit. Numerical experiments on a real-world load and PV data set show the state-of-the-art performance of the proposed model, both for the BTM disaggregation and forecasting tasks.

Aerodynamics of air-permeable multilayer roof cladding

Currently, design approaches to determine loads on different types of building cladding elements can vary significantly by product type, even though they may have similar geometries. Using the full-scale wind tunnel at the Insurance Institute for Business & Home Safety, external and net wind loads on two discontinuous metal roof systems were measured. The results indicate that cavity pressures in air-permeable multilayer cladding, such as discontinuous metal roofs are approximately uniform across individual panels and closely related across multiple panels which share the same cavity. The testing also showed that peak net loads tend to occur slightly after the peak spatial gradient of the external pressure across the cladding elements. The two types of discontinuous metal roofing products, which have significantly different cavity geometries, have similar ratios between the net and external wind loads with metal shingles having a Ceq value of 0.55 and metal panels having a Ceq value of 0.67. Overall, these experimental results indicate that the peak pressure equalization factor is dependent on the external pressure difference across the cladding, the geometry of the cladding, and the fluid inertia of the cavity flow. The experimental results also show that the peak pressure equalization factor is not dependent on location and wind direction, for panels that are not adjacent to the edges.

Distributed Robust Adaptive Frequency Control of Power Systems With Dynamic Loads

This paper investigates the frequency control of multi-machine power systems subject to uncertain and dynamic net loads. We propose distributed internal model controllers that coordinate synchronous generators and demand response to tackle the unpredictable nature of net loads. Frequency stability is formally guaranteed via Lyapunov analysis. Numerical simulations on the IEEE 68-bus test system demonstrate the effectiveness of the controllers.

A Fast LP-Based Approach for Robust Dynamic Economic Dispatch Problem: A Feasible Region Projection Method

The robust optimization based dynamic economic dispatch (DED) model has been extensively studied to address uncertainties of net loads induced by renewable energy resource variabilities and demand fluctuations. However, the robust DED model is computationally expensive, when solved by the column-and-constraint generation (CCG) approach that iterates between a master problem and a max-min subproblem. This letter proposes a feasible region projection-based approach to equivalently reformulate the robust DED as a single-level linear programming (LP) model that can be effectively solved while guaranteeing solution optimality. Numerical studies show the proposed approach is one order of magnitude faster than CCG.

Dynamic behaviour of DEMO vacuum vessel during plasma vertical displacement events

In tokamaks during plasma vertical displacement events (VDEs) electrical currents occur in the vacuum vessel (VV) and in the in-vessel components (IVCs) that interact with the strong magnetic field generating large electromagnetic (EM) loads. The aim of the present work is the evaluation of the peak displacements and accelerations of the DEMO VV in case of VDEs. Four types of VDEs are investigated that are specified to generate the most severe net loads. The assessment considers also the electromagnetic-mechanical coupling between the VV and the toroidal field (TF) coils whose characteristic stiffness and damping coefficients were determined through a transient EM analysis. In a second step a transient dynamic analysis was performed using a structural finite element (FE) model of the VV to evaluate the displacement and acceleration peaks during the VDEs in relevant locations of the VV.

System-level modeling methodology for capturing the pile cap, helical pile group, and soil interaction under uplift loads

In tall and light structures, such as transmission towers, wind turbines, and light-gauge steel structures, there is an increasing application of pile cap with helical pile foundation systems to resist the uplift loads due to the effects of windstorms and earthquakes. There is a lack of knowledge, published literature, or analysis methods to account for the effects of the pile cap, helical pile group, and soil interactions on the holistic response of the foundations, particularly, for the load conditions creating net uplift loads. In the lack of such, discrete modeling approaches are frequently employed in practice. These approaches isolate each system component and analyze them individually, neglecting the interactions between them. In an attempt to bridge this knowledge gap, this study proposes a system-level modeling methodology for the holistic analysis of pile cap systems in dry soil and static load conditions, while accounting for the effects of interactions between system components and the inherent material nonlinearities. The methodology employs a three-stage process in which the material and interaction properties are calibrated with the experimental benchmark specimens. The failure mechanisms are also experimentally verified based on the relative displacement of the piles. Important modeling considerations are discussed, and experimental benchmark specimens are provided to assist practitioners in accurately performing system-level analyses. The effectiveness of the proposed methodology is discussed, and the responses obtained, including the load–displacement responses, load capacities, and failure modes, are compared with those obtained from the discrete modeling approaches. The results demonstrate that discrete modeling approaches significantly underestimate the load capacity while not accurately predicting the governing behavior and the failure modes.

Monitorowanie oraz bazująca na danych predykcja parametrów roboczych przemysłowej turbiny gazowej

The article reviews traditional and modern methods for prediction of gas turbine operating characteristics and its potential failures. Moreover, a comparison of Machine Learning based prediction models, including Artificial Neural Networks (ANN), is presented. The research focuses on High Pressure Compressor (HPC) recoup pressure level of 4th generation LM2500 gas generator (LM2500+G4) coupled with a 2-stage High Speed Power Turbine Module. The researched parameter is adjustable and may be used to balance net axial loads exerted on thrust bearing to ensure stable gas turbine operation, but its direct measurement is technically difficult implicating the need to indirect measurement via set of other gas turbine sensors. Input data for the research have been obtained from BHGE manufactured and monitored gas turbines and consists of real-time data extracted from industrial installations. Machine learning models trained using the data show less than 1% Mean Absolute Percentage Error (MAPE) as obtained with the use of Random Forest and Gradient Boosting Regression models. Multilayer Perceptron Artificial Neural Networks (MLP ANN) models are reviewed, and their performance checks inferior to Random Forest algorithm-based model. The importance of hyperparameter tuning and feature engineering is discussed.

Adaptive time division power dispatch based on numerical characteristics of net loads

Energy sustainable development is of strategic importance across the world. This is especially the case in China as it is the world’s largest energy consumer. However, renewable energies such as wind and solar energy are characterized with high intermittence and fluctuation. As the penetration of renewable power in the energy system increases, it is getting more challenging in power dispatch. In this paper, an adaptive time division power dispatch strategy based on numerical characteristics of net loads is proposed. In this strategy, a dispatch time division method is introduced in detail to divide the dispatching time according to the numerical characteristics of net loads. The sample entropy theory is utilized to calculate the complexity of the net loads, depending on which a specific thermal generating mode is provided. The experiment simulation is developed on an actual provincial power system in the northeast of China. The test results have confirmed that in the adaptive time division power dispatch strategy, the ramping power of thermal generators are decreased, the continuous and steady operation time of thermal generators are improved. As a result, this new strategy, can lead to improved energy efficiency of power systems as well as significant environmental benefits.

Between-Limb Differences in Patellofemoral Joint Forces During Running at 12 to 24 Months After Unilateral Anterior Cruciate Ligament Reconstruction

Background: Patellofemoral joint (PFJ) osteoarthritis may occur after anterior cruciate ligament reconstruction (ACLR). The mechanisms underpinning the development of PFJ osteoarthritis are not known but may relate to altered PFJ loading. Few studies have assessed PFJ loads during high-impact tasks, such as running, beyond the acute rehabilitation phase (ie, >12 months) after ACLR. Purpose/Hypothesis: The purpose was to compare between-limb joint angles, joint moments, and PFJ contact force during running in individuals at 12 to 24 months after unilateral ACLR. We hypothesized that peak knee flexion angle, knee extension moment, and PFJ contact force during stance would be lower in the ACLR limb compared with the uninjured limb. Study Design: Controlled laboratory study. Methods: A total of 55 participants (mean ± SD age, 28 ± 7 years), 12 to 24 months after ACLR, ran at a self-selected speed (2.9 ± 0.3 m/s). Measured kinematics and ground-reaction forces were input into musculoskeletal models to calculate joint moments and muscle forces. These values were subsequently input into a PFJ model to calculate contact force peak and impulse. Outcome measures were compared between the ACLR and uninjured limbs. Results: In the ACLR limb, compared with the uninjured limb, the PFJ contact force displayed a lower peak (ACLR, 6.1 ± 1.3 body weight [BW]; uninjured, 6.7 ± 1.4 BW; P < .001) and impulse (ACLR, 0.72 ± 0.17 BW*seconds [BWs]; uninjured, 0.81 ± 0.17 BWs; P < .001). At the time of the peak PFJ contact force, the knee extension moment was lower in the ACLR limb (ACLR, 14.0 ± 2.4 %BW*height [%BW*HT]; uninjured, 15.5 ± 2.5 %BW*HT; P < .001). The opposite was true for the ankle plantarflexion moment (ACLR, 12.1 ± 2.6 %BW*HT; uninjured, 11.5 ± 2.7 %BW*HT; P = .019) and the hip extension moment (ACLR, 2.3 ± 2.5 %BW*HT; uninjured, 1.6 ± 2.3 %BW*HT; P = .013). The foot-ground center of pressure was located more anteriorly with respect to the ankle joint center (ACLR, 5.8 ± 0.9 %height [%HT]; uninjured, 5.4 ± 1.0 %HT; P = .001). No differences were found for the sagittal plane hip, knee, and ankle angles. Conclusion: The ACLR limb experienced lower peak PFJ loads during running, explained by a small anterior shift in the foot-ground center of pressure during stance that offloaded the torque demand away from the ACLR knee. Clinical Relevance: Lower net PFJ loading during running in the ACLR limb more than 12 months after ACLR suggests that underloading might play a role in the onset of PFJ osteoarthritis after ACLR.

Carbon harvesting from organic liquid wastes for heterotrophic denitrification: Feasibility evaluation and cost and emergy optimization

Organic liquid hazardous wastes (LHWs) consist of plentiful, valuable carbon sources, during the recovery of which, simultaneous disposal of high-NO3− and organic LHWs is possible for the control of organic and nitrogen pollution. In this study, we propose an anaerobic hydrolytic acidogenic and denitrification integrated (AHDI) process and carefully evaluate the technical, economical, and sustainable properties toward this simultaneous disposal strategy using long-term pilot experiments. With consistently increasing initial nitrate (NO3−) concentrations ([NO3−]0) from 355 to 30,000 mg/L and salinity from 0.5% to 7.8%, high removal efficiencies of 99.5% and 65.7% were observed for NO3− and chemical oxygen demand (CODCr), respectively, and the optimum C/N ratios were determined to be above 1.0 using volatile fatty acids (VFAs) upon the anaerobic hydrolytic acidification of organic LHWs as electron donors. A NO3− loading rate as high as 33.2 kg NO3−•m3/d was achieved at [NO3−]0 of 30,400 mg/L, and the concentrations of NO3− and nitrite (NO2−) in effluents were observed to be as low as 33.1 and 0.11 mg/L, respectively. Moreover, cost and emergy analysis indicated that the net annual cost and environmental loading ratio (ELR) were 42.3% and 47.6%, respectively, of those involved in the traditional separate disposal strategy. The proposed simultaneous disposal strategy is cost-effective and sustainable and exhibits improved emergy saving with lower environmental stress and less nonrenewable inputs required than the traditional process.

Wind pressures on a large span canopy roof

Based on wind tunnel tests, this paper investigates the aerodynamic behavior of a large span canopy roof with elliptical plan and hyperbolic paraboloid shape. The statistics of pressure coefficients and the peak factor distributions are calculated for the top and bottom faces of the roof, and the Gaussian or non-Gaussian characteristics of the pressure time-histories in different areas of the roof are discussed. The cross-correlation of pressures at different positions on the roof, and between the top and bottom faces is also investigated. Combination factors are also evaluated to take into account the extreme values of net loads, relevant to the structural design of canopies.

Effectiveness of Amine Concentration and Circulation Rate in the CO2Removal Process

AbstractOptimization of an amine‐based method is vital to ensure product quality, equipment safety, and system efficiency. Here, the effectiveness of amine concentration and circulation rate is evaluated for a diglycolamine (DGA)‐based facility. The performance is measured using the concentration of carbon dioxide in the treated gas and the net acid gas loading of the amine solution. Both amine concentration and circulation rate were observed to affect the system efficiency. An optimal operating range was identified for the gas plant studied established on the performance criteria. The analysis is based on a proprietary mass transfer‐based process simulator of an amine‐based acid gas treating facility and field data.

Experimental Assessment of Wind Loads on Roof-to-Wall Connections for Residential Buildings

Wind hazards are one of the most disastrous events that frequently occur in the United States. Hurricane Irma, which hit the southeast coast in 2017, left a majority of damage concentrated on low-rise buildings and wooden construction in its wake. As revealed by recent hurricane damage reconnaissance, hardware-type roof-to-wall connections are especially vulnerable to high wind suction. There is only limited research on the assessment of wind loads on these roof-to-wall connections, which are important components of the wind load path. Hence, it is essential to have realistic estimates of wind effects on these connections to ensure a safe design. To fill this fundamental knowledge gap, an extensive large-scale aerodynamic testing study has been recently conducted at the NSF-Natural Hazard Engineering Research Infrastructure (NHERI) Wall of Wind (WOW) Experimental Facility (EF) to investigate wind actions resulting from simulated hurricane force winds. A wooden gable roof building of a large length scale of 1:4 was adopted for this study. Seven trusses were used to construct the roof and were connected to the top plate of the side walls. Load cells were mounted at the roof-to-wall connection (RTWC) level to measure the effective net wind-induced forces. The model was tested under different wind directions varying from 0° to 360° with an increment of 5° under varying wind speeds. In addition, three different configurations, i.e., one enclosed and two partially enclosed, were considered to assess different internal pressure scenarios that affect the net load-ing on the roof-to-wall connections and the overall roof system. The RTWC force coefficients distribution along the entire roof was obtained. The results were compared to force coefficients recommended by ASCE 7-16 version for the cases of Main Wind-Force Resisting System (MWFRS) and Component and Cladding (C&C). The experimental results were in between MWFRS and C&C values based on the ASCE provisions in general. However, for partially enclosed case, some values slightly exceeded those based on the ASCE C&C provisions. Also, the overall uplift on the roof was found to be dependent on the location of the opening (i.e., opening on long side versus short side of the building).

Integrated iterative musculoskeletal modeling predicts bone morphology following brachial plexus birth injury (BPBI)

Brachial plexus birth injury (BPBI) is the most common nerve injury among children. The glenohumeral joint of affected children can undergo severe osseous deformation and altered muscle properties, depending on location of the injury relative to the dorsal root ganglion (preganglionic or postganglionic). Preganglionic injury results in lower muscle mass and shorter optimal muscle length compared to postganglionic injury. We investigated whether these changes to muscle properties over time following BPBI provide a mechanically-driven explanation for observed differences in bone deformity between preganglionic and postganglionic BPBI. We developed a computational framework integrating musculoskeletal modeling to represent muscle changes over time and finite element modeling to simulate bone growth in response to mechanical and biological stimuli. The simulations predicted that the net glenohumeral joint loads in the postganglionic injury case were nearly 10.5% greater than in preganglionic. Predicted bone deformations were more severe in the postganglionic case, with the glenoid more declined (pre: −43.8°, post: −51.0°), flatter with higher radius of curvature (pre: 3.0 mm, post: 3.7 mm), and anteverted (pre: 2.53°, post: 4.93°) than in the preganglionic case. These simulated glenoid deformations were consistent with previous experimental studies. Thus, we concluded that the differences in muscle mass and length between the preganglionic and postganglionic injuries are critical mechanical drivers of the altered glenohumeral joint shape.

Wind-Thermal-Nuclear-Storage Combined Time Division Power Dispatch Based on Numerical Characteristics of Net Load

In order to satisfy the strategic needs of energy sustainable development, renewable energy has developed rapidly and the power systems have been transformed to a new generation of power systems. In the renewable energy power generation technologies, the fastest developing wind power generation are highly intermittent and fluctuating. When high penetration of renewable power connects to the power grid and participates in the system dispatch, there will be more difficulties and challenges in the energy balance control. In this paper, a wind-thermal-nuclear-storage combined time division power dispatch strategy based on numerical characteristics of net load is proposed, where a specific thermal generating mode and an unconventional nuclear generating mode are discussed. In the strategy, the dispatch time division method is introduced in detail and the sample entropy theory is used to calculate the net load complexity. An adaptive thermal generating mode is determined according to the numerical characteristics of the net load. The nuclear generating modes of constant power operation, time division operation, and net load tracking time division operation are compared and analyzed, respectively. Finally, the wind-thermal-nuclear-storage combined time division power dispatch strategy aiming at decreasing the ramping power of thermal generators is achieved, and the increasing of the participation of pumped storage and improving of the continuous and steady operation time of thermal generators are realized. The experiment simulation is developed on an actual provincial power system in the northeast of China. The results verify that the thermal generator ramping power in the case based on SampEn are reduced, and the participation of pumped storage is improved. When both of the thermal generating mode and nuclear generating mode are according to the changing of net loads, the ramping powers of thermal generators are further decreased.