Hydropower and Renewable Energies

Cracks as the main safety concern of dams, high-precision identification of dam cracks is of great application value and scientific significance to ensure the safety of dams. The paper proposes a dam crack identification method based on multi-source information fusion. Specifically, image gray scale and geometric features are extracted based on the image information. And then a single crack identification model based on Support Vector Machine (SVM), Decision Tree (DT), Random Forest (RF), XGBoost, and BP Neural Network are established based on the features, respectively. Finally, a multi-classifier fusion algorithm based on D-S evidence theory is established to identify the presence of cracks by fusing single identification models. Experiments are carried out to compare the proposed method with the existing identification methods based on the evaluation metrics such as accuracy, precision, F1-score, and recall. The results show that the accuracy of crack identification of the proposed method in this paper reaches 98.9%, and the crack identification results are better than the existing methods.

With the new technologies applied in the Power Electrical System, we enable the shared use of the Ultraviolet Measurement Apparatus, for Corona Measurement (the corona effect is just one type of partial discharge characterized by its visibility when propagating in external mediums due to electric field - potential) in Transmission Lines, into the Assets of Hydropower Plants with rotating machinery from Small Hydropower Plants - SHPs, within Predictive Maintenance. The gain from this Predictive Maintenance brought evaluation benefits in the reception after treatment of generators related to Partial Discharge on the surface, particularly the part related to surface corona effect on rotating machinery. Measurements before and after surface treatment recovery, mainly in coil heads and other parts of the generating unit, show us the results more through frequency spectrum, ranges, and events/minutes measures, associated with a scale already worked for measurement points in Transmission Lines assets, values understood above 5000 events/minutes and mainly the region with the highest concentration of records signaling points to improve or redo specific treatment. It's worth mentioning here that it doesn’t substitute tests by offline and online partial discharge devices in peak measures (pC) or nano Coulomb (nC), but it brings the focus spectral sampling region that deserves more attention or reinforcement in treatment to mitigate corona effect, also can be used to evaluate generator cleanliness when intensities are recorded in predictive maintenance. The SBUV camera, Solar Blind filter, has higher sensitivity, compatible wavelength, bi-spectral, and a range from 240 nm to 280 nm (nanometers), which can bring gains in this technological application. The tool, when customized, provides risk assessment for each generator in trials and ensures an operational view of the Asset from the perspective of its health in this regard - Health Index. The new technology is already implemented and has been successfully used in our plant, in its punctual maintenance plan regarding measuring, evaluating own or third-party services, and determining the best time to act in new surface treatments or asset cleaning, mitigating the risk of early burnout due to this phenomenon. Direct gains in application come from the integration of Asset Management with Reliability-Centered Maintenance, optimizing the Maintenance Plan and the concepts of Engineering Applied to the company's Assets.

Finite element analysis was conducted on the stress, vertical displacement, and horizontal displacement of ordinary concrete and ductile concrete gravity dams under different working conditions. The results show that: with the decrease of the height of the dam, the stresses on the two concrete dams gradually increase, and the vertical displacements show a decreasing trend during the operation period. Under the effect of earthquakes, the maximum stress of the two kinds of concrete gravity dams appears at the weak point of the dam body. The maximum stress of the normal water level and the falling water level of the ordinary concrete dam reach 9.91 MPa and 9.85 MPa respectively. The maximum stress of two types of concrete dams under seismic conditions is approximately 4 times that of the operation period. Under different working conditions, the maximum stress and displacement of the ordinary concrete are always smaller than that of ductile concrete.

In order to solving the problem of tolerance in the mixing of water workers’ consolidation processes, Hydraulic High Ductile Concrete (HHDC) was prepared by using lower cost centimeters and TY-PVA fibers. The effects of sand-binder ratio, fly ash dosage, rubber powder dosage and fibre dosage on the performance of HHDC were investigated. The results show that among the four influencing factors, the rubber powder dosage and sand-binder ratio have a more significant impact on the flexural load, with HHDC-1 having the highest flexural load of 3.49 kN. While the fiber dosage and fly ash dosage have a significant impact on the ultimate deflection, with HHDC-7 having the maximum ultimate deflection of 0.60 mm. Each group of HHDC exhibits ductile failure characteristics during the bending process. The conclusion of the study can provide some theoretical support for the engineering application and promotion of HHDC.

With the opportunities brought by China’s promotion of achieving the “dual carbon” targets, the technology of China’s photovoltaic industry is accelerating improvement, and the scale is steadily expanding. Distributed photovoltaic projects have the advantages of flexible configuration, nearby utilization, low investment, and saving land resources, with huge market space and development potential. Although the photovoltaic industry has enormous growth potential and good market prospects, it also faces many risks and challenges such as consumption problems and unstable income. Therefore, studying the economic viability of distributed photovoltaic projects is of great significance for making project investment decisions and promoting the sustainable development of the industry. This paper conducts the economic analysis of distributed photovoltaic power generation projects, calculates profitability analysis indicators such as financial internal rate of return (IRR) of project investment, financial net present value of project investment, and payback period of project investment. It also conducts preliminary sensitivity analysis on uncertain factors such as construction investment, operating revenue, and operating cost. It conducts in-depth sensitivity analysis on consumption, grid electricity price, and self-use electricity price, and proposes countermeasures to improve the economic efficiency of distributed photovoltaic power generation projects. The research results may provide reference and guidance for similar project investment decisions in more challenging investment environments in the future.

The development of new technologies has greatly promoted the progress of dam safety monitoring technology, mainly reflected in the construction of monitoring norms and standards and technical applications. In terms of monitoring norms and standards construction, this paper mainly introduces the achievements made by China in the construction of monitoring norms and standards for dam safety. In terms of monitoring the application of new technologies, the improvement of monitoring technology and equipment perception is introduced, as well as the construction of monitoring system platforms. Finally, providing an outlook on the areas where current monitoring technologies need to be improved and enhanced.

The traditional centralized or monolithic application architecture can no longer meet the needs of modern hydraulic engineering safety supervision, especially when dealing with business expansion and system upgrades, it is easy to encounter bottlenecks. This paper designs a hydraulic engineering safety supervision platform based on microservice architecture. Firstly, the service partitioning was carried out by researching microservice partitioning methods and integrating them with the specific characteristics followed by a detailed introduction of the platform's implementation process. By applying microservice selection in Shanmei renovation project, it has been verified that the platform can significantly improve the efficiency and accuracy of safety monitoring, and provide flexible and scalable solutions for other hydraulic projects.

Failure to meet specific standards for slope stability conditions may result in the potential collapse of the slope, either partially or completely. The article focuses on slope engineering and examines the structure and components of a comprehensive digital twin system. It also explores the digital technologies used in this system and assesses its unique features and innovative applications in slope construction. The architecture of the digital twin system for rock slopes must cater to the requirements of multiple professionals, comprehensive process coverage, and data-centricity. It should ensure the separation of software and personnel, with key technologies such as 3D geological modeling and rapid updates, GIM+BIM coupling modeling, and challenging techniques like cutting and sealing. Independent innovation is crucial to address these key technologies. During the slope construction period, the digital twin system of rock slope is utilized to intelligently screen unstable blocks. This innovative approach has been successfully implemented and verified in numerous large-scale rock mass projects, with favorable implementation conditions.

Climate change has resulted in an increase in extreme weather events, with a sharp rise in droughts and floods. To establish a long-term mechanism for ensuring the safe operation of the Three Gorges Project, it is imperative to utilize hydrodynamic methods to analyze the water level operation mode during the flood season. This is crucial to enhancing the flood control safety and maximizing the overall benefits of this project. Therefore, this study obtained four different frequency design flood processes for each year by utilizing data from typical years. And the influence of different starting water level and discharge flows on the high water level and excess flood volume of flood regulation were revealed under the existing scheduling protocols and a one-dimensional hydrodynamic model. The results indicated that the water level operation modes of floods from different typical years were significantly different under the same scheduling rules, and when faced with the extreme flood conditions, discharge flow is a primary determinant of reservoir safety. Furthermore, the current scheduling scheme for the Three Gorges Reservoir has an extra safety margin. As a result, even without forecasting inflows, elevating the operating water level to 155 m during the flood season effectively mitigates risks from floods with a return period of 100 years or less, while maintaining risk control over floods with 1,000-year or 10,000-year return periods.

Accurate runoff forecasting is of great significance for flood control, drought prevention, reservoir scheduling, and ecological protection. To explore the applicability of deep learning networks combined with signal processing techniques in runoff forecasting, an ICEEMDAN-VMD-CNN-LSTM daily runoff forecasting model for the flood season was developed. First, the original runoff series was decomposed using the Improved Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (ICEEMDAN). Then, the complex series was further decomposed using Variational Mode Decomposition (VMD) to reduce data complexity. Next, each mode component was input into a Convolutional Neural Network (CNN) - Long Short-Term Memory (LSTM) combined model to extract local features of the data and capture long-term dependencies of the time series. Finally, the predicted values were reconstructed to obtain the final prediction results. Using the measured daily runoff data from the Hekou station in the Diaojiang basin as an example, the results showed that the ICEEMDAN-VMD-CNN-LSTM achieved testing MAE and NSE of 5.232 m3/s and 0.977, respectively, demonstrating excellent forecasting accuracy.

In the construction of domestic concrete high arch dams, there have been varying degrees of situations where the height difference between adjacent dam sections and the entire dam exceeds the design indicators. Due to the complex structure, large scale, high temperature control requirements for the dam body concrete, strict control requirements for the height difference between adjacent dam sections and the entire dam body, and complex boundary conditions, the rising speed of the bank slope dam section, non-orifice dam section, and orifice dam section is not consistent during the construction process, resulting in uneven rise of the dam concrete construction. In response to this situation, the resources need to be fully considered according to the simulated schedule of dam concrete construction. In this research, the finite element, PKPM and other software were used to study technical measures for rapid rise of the bank slope dam section and orifice dam section, and achieved the goal of balanced rise of the Baihetan concrete arch dam.

Compared with the operation of a single hydropower station, the difficulty of operation and management for cascade hydropower stations increases exponentially. Especially during the critical periods such as concentrated drawdown before flood season and concentrated storage during late flood season, the dispatching strategies of cascade stations are crucial for successfully realizing operation objectives and enhancing power generation benefits of the cascade system. Scientific methods should be used to formulate long-, medium-, and short-term operation strategies, and the sequence of drawdown or storage for cascade reservoirs should be arranged reasonably to maximize the system benefits. Current research typically utilizes reservoir dispatching diagrams or optimal dispatching models to develop scheduling plans. Reservoir dispatching diagrams can be used to quickly access the operation schemes for reservoirs, but it cannot guarantee the optimal power generation benefits within a given dispatching period. Optimal models typically utilize algorithms such as dynamic programming to solve and obtain corresponding scheduling solutions, achieving the maximization of reservoir dispatching objectives. However, the problem of dimension disaster often easily occurs. To balance the optimization of system benefits and the efficiency of formulating operation plan, this paper proposes a benefit evaluation index, namely Benefit Variation from Water Storage (BVWS), which simultaneously couples water head benefits and backwater jacking influence of hydropower stations.Based on this, the graphs of BVWS for cascade stations are drawn, which can assist decision-makers in quickly formulating dispatching strategies for different time scales. Taking a cascade system composed of four hydropower stations in the upper reaches of the Yangtze River as the research object, this paper compares the calculation results and efficiency of the proposed method with the progressive optimality algorithm (POA). The results indicate that the proposed method can remarkably reduce the time required to develop optimal operation schemes, enabling a rational allocation of water resources among the cascade stations, therefore proving the scientific rationality of this method.

Hydropower and renewable energy prediction require accurate precipitation forecast as fundamental, which is computed from Numerical Weather Forecast (NWP) models. Assimilating satellite data has become an important method to improve NWP model results, especially geostationary meteorological satellites (GMS) that can provide continuous observation information of weather systems. The Advanced Geostationary Radiance Imager (AGRI) onboard China’s new generation GMS, FY-4A, can provide observations of temperature and water vapor covering the land and surrounding sea areas. Using a newly established WRF-GSI NWP system, this paper analyzes the impact of AGRI data assimilation on several precipitation case forecasts in China. First, channel selection of AGRI data, along with data thinning and observation error adjustment are performed. Then, four experiments of precipitation case forecasts are conducted and compared with each other. The results show that the influence of assimilating conventional data is mainly located in the inland area of China, while AGRI data can provide more observation information in the offshore ocean area. AGRI data assimilation can significantly improve the accuracy of atmospheric temperature and water vapor at a height of 500 hPa in the coastal area of the model, which further enhanced precipitation forecasts. The improvement of ETS score for heavy precipitation is most obvious, the biggest improvement can be up to 60% in the 15 July 2021 case, indicating the addition of AGRI data can ensure the improvement of the ETS scores of heavy precipitation that larger than 50 mm. The results prove that the AGRI data has added value to precipitation forecasts in the WRF-GSI NWP system, the improved forecast accuracy has great potential on hydrological forecasts, supporting the development of related hydropower applications.

This paper presents seismic measurements at a large hydroelectric power plant dam in the south of Brazil. The seismic measurements were realized using optical fibre distributed sensor system technology and aim at diagnosing possible structural problems inside of the dam. Studies carried out at a laboratory scale dam using geophones as well as optical fiber sensors are also presented. Results are very promising and indicate the potential of the technology using both active and passive seismic techniques to solve major monitoring problems that cannot be addressed by today’s technology.

An in-depth research was conducted on the real-time scheduling issues involved in the joint operation of runoff cascade hydropower station under high-intensity peak-load regulation and frequency regulation requirements, and proposed an intelligent control method for real-time load regulation of runoff cascade hydropower stations. Based on the characteristics of real-time power generation scheduling of cascade hydropower stations, ensuring the effectiveness and flexibility of scheduling strategies, taking into account the constraints of reservoir operation, grid safety, unit operation, and the impact of different water heads on unit power generation efficiency, aiming to achieve stable water level control of runoff type hydropower stations and rapid response of cascade total load control. Real time load Control is divided into two categories: dispatching mode and non dispatching mode. In the dispatching mode, constructed water power determination, stable water level, less load regulation, load balance economic dispatching models, to predict in advance whether the day ahead load planning curve needs to be adjusted and automatically track the planning curve. In non dispatch mode, automatically match the abnormal water level control model based on PID regulation and the stable water level model that meets the requirements of efficient power generation. At the same time, proposed a water level control solution method based on successive approximation and multi-objective dynamic programming, as well as a mixed integer programming model for reducing the difficulty of solving real-time hydropower scheduling for load allocation. The application of the proposed model in the cascade hydropower stations in the Shaxi River Basin shows that it can achieve high-precision automatic load adjustment, effectively reduce the number of regulation times by 6%, and only retain one dispatcher per shift, greatly reducing the work intensity of operators on duty. This research effectively improves the centralized control capability and economic operation level of the watershed, and has rich theoretical and practical significance for promoting the intelligent and intelligent construction of real-time load scheduling for cascade power stations.

The artificial sand and stone processing plant has always been a major pollutant discharge household in hydropower station construction, and the problems of dust and waste water are more prominent. In order to solve the problem of waste water, the artificial sand and stone processing system often uses the wet production process, combined with the sewage treatment facilities to treat the waste water produced by the system, and the pollution particles are precipitated and dehydrated again. The proper measures can realize the zero discharge of waste water. The treatment method of flocculation sedimentation and mechanical dehydration is often used in domestic sand and stone processing system wastewater. The key of the treatment process is flocculation sedimentation, and the control of sludge floc formation speed and separation effect. This paper introduces a new flocculation and sedimentation technology “tower type cyclone stabilizing cylinder concentration technology”. This technology absorbs the advantages of tower type sedimentation technology and cyclone type sedimentation tank technology. By setting up mixed flow tank, stabilizing cylinder and other structures, and combining with field flocculation test and technical fine-tuning, the optimal dosage of flocculant is determined, so as to control the formation speed and separation effect of sludge flocs in a relatively ideal range Status. The process has been successfully applied in the no wastewater treatment of the sand and gravel processing system of Batang hydropower station, and good results have been achieved, which is worthy of reference.

The seismic safety evaluation of the dam is performed based on either dam strength failure or dam abutment instability failure according to the traditional deterministic methods and concepts in the current code. However, these two failure modes are interactive and inseparable, considering only one failure mode under a strong earthquake fails to fully reflect the actual seismic performance of high arch dams. To develop a more realistic seismic safety evaluation framework for high arch dams, this paper constructs a finite element analysis model that considers the coupling of dam strength failure and dam abutment instability failure. The nonlinear dynamic response analysis of the high arch dam-foundation coupling system is conducted using the seismic overload analysis method. Different performance evaluation indexes, such as damage depth-thickness ratio, sliding area ratio, and the residual displacement of the dam crest relative to the dam bottom in the stream direction, are proposed. The performance evaluation criteria and ultimate seismic capacity are defined and quantitatively assessed. The results indicate that 2.0 times the horizontal PGA can be considered the ultimate seismic capacity of the high arch dam-foundation coupling system, providing a reliable scientific basis for seismic safety evaluation of high arch dams.

A two-dimensional flow and sediment model was used to study the sedimentation problem of a high head and high sand content hydroelectric power station in Nepal. Under the layout scheme of “reservoir replacing pool + bypass flushing”, a total of 12 sediment discharge operation schemes were proposed for the reservoir area under the combination of 3 flow limits and 4 sand discharge water levels. The results show that: After 5 years of operation of the project, there is a difference in the elevation of the sedimentation surface in front of the water intake. Different sand flushing operation methods have a significant impact on the elevation of the sedimentation surface in front of the water intake during the period of 7–17 years. Under various schemes, the trend of the elevation change of the sedimentation surface in front of the water intake after 17 years of operation of the head hub is basically consistent, and the difference is not significant. The elevation of the sedimentation surface in front of the water intake can be controlled at around 2505 m under each scheme; When operating at a sand discharge water level of 2520 m, the elevation of the sedimentation surface in front of the sand discharge tunnel can be controlled at around 2510 m, and the probability of sedimentation in the bypass sand discharge tunnel is not high; The project operates for about 10–15 years and is basically in a balanced state; Under the condition of 2520 m sediment discharge water level, the remaining effective storage capacity of the hub is larger after 20 years of operation under each scheme; This project follows the 2520 m sediment discharge water level scheme. When operating at a sediment discharge flow limit of 120 m3/s, the effective storage capacity of the reservoir meets the requirements of the designed daily regulating storage capacity. Therefore, it is recommended that this project operate according to the 2520 m sediment discharge water level scheme.

The paper focuses on how to rationally distribute the load of cascade hydropower station in the short term economic operation to meet the grid requirements and improve the water energy efficiency of cascade hydropower stations. In this paper, a calculation method of energy storage for cascade hydropower station is presented, the change of cascade storage caused by power generation of different hydropower stations is studied, and the influence of reservoir capacity characteristics on load distribution of cascade hydropower stations is analyzed. According to the short term economic operation and dispatching requirements of cascade hydropower station, the load distribution model of cascade hydropower station based on the maximum storage capacity at the end of the term is constructed. Taking the short-term load distribution of cascade hydropower stations in the Nam Ou River Basin of Laos as an example, four scheduling schemes with different boundary conditions are calculated. The results show that the load distribution results of cascade hydropower stations in the Nam Ou River based on the maximum energy storage the end of the period are as follows: Nam Ou4 and Nam Ou1 in the downstream with larger changes in water level per unit storage capacity are preferentially stored, Nam Ou7, Nam Ou6 and Nam Ou2 in the upstream with larger storage capacity are preferentially supplied and generating power. The research results can provide guidance for the short-term economic operation and dispatch of cascade hydropower stations, and help to improve the water energy utilization efficiency of cascade hydropower stations.

In recent years, countries and regions worldwide have set goals to increase the proportion of new energy source in their energy transition plans. However, the intermittent nature of new energy sources, represented by wind power and solar photovoltaics, necessitates the support of flexible resources like pumped storage and hydropower. This study takes the established Liyuan and Ahai Hydropower Stations along the Jinsha River as typical cases, thoroughly exploring the potential benefits of utilizing the reservoirs of these two stations to construct a Liyuan-Ahai hybrid pumped-storage power station. Through comprehensive analysis, we propose an installed capacity scheme that aims to maximize the benefits of the three power stations. This scheme not only provides a feasible reference method for the design of similar engineering projects, but also holds significant importance in promoting the efficient utilization and sustainable development of hydroelectric energy. We hope that through this research, we can provide valuable reference and inspiration for experts and scholars in the field of hydropower engineering.

The most prominent engineering geological problem of pumped storage power station reservoirs in karst areas is karst leakage, the development of karst leakage channels has a significant impact on the selection of reservoir locations, layout of engineering buildings, design of anti-seepage measures, and engineering costs. Therefore, the survey and evaluation of reservoir leakage channels are the foundation for the construction of pumped storage power station reservoirs in karst areas. The field analysis method plays an important role in karst leakage survey. Traditional karst groundwater field analysis methods, based on the representative indicators of each field measured and determined by experience, fail to fully reflect the temporal and spatial change information of each field indicator, and the data cannot be fully utilized and compared for verification. The multi field data fusion analysis method for karst groundwater proposed in this article comprehensively considers the relationship between measured field indicators and leakage sources, natural conditions, adjacent spaces, and different time field indicators， and obtains the characteristic values of the tracer index, background index, gradient index, and time series index of each field, and overlay calculation of single field comprehensive eigenvalues and multi field composite eigenvalues, which can realize the fusion of multiple fields and multiple indicators, amplify the abnormal location signal of seepage, and delineate the location of centralized seepage, so as to quantitatively determine the location information of the seepage channel of karst groundwater. This method is applied to the survey of karst leakage in the lower reservoir of a pumped storage power station in Guizhou Province, field data fusion analysis shows that there is an abnormal seepage field in the anti-seepage curtain line of the site, and there is good evidence for the temperature and conductivity field data. There is a deep karst leakage channel in the reservoir; The burial depth of the channel is more than 170 m below the normal water level. The research results can provide support for subsequent anti-seepage methods and engineering treatments, as well as relevant engineering experience for other projects.

After a strong earthquake occurs, it can cause a certain degree of damage to the structure, and the strong aftershock effect can cause secondary damage to the already damaged structure. In this study, taking a actual project of intake tower in the district of western strong earthquake as an example, the acoustic unit is used to simulate the dynamic effect of reservoir water on the tower body, and the overall nonlinear model of the water-intake tower-foundation is established. Combined with the site and seismic motion characteristics of the engineering area, the seismic motion sequence of the main-aftershocks was constructed based on the statistical relationship between the main shocks and strong aftershocks, as well as the NGA seismic motion attenuation model. The effects of main shock, aftershock, and main-aftershock on the structural damage evolution of intake towers in strong earthquake zones were investigated separately. The results show that after considering the aftershock effect, the damage and failure of the intake tower structure intensify, and its dissipation energy and residual displacement increase by about 20%~25%. Compared with the main shock, the aftershock alone causes less damage to the tower structure. However, for the intake tower structure that is damaged after the main shock, the aftershock can cause larger secondary residual deformation of the tower.

Taking the underground cavern group of Dadu River Jinchuan Hydropower Station as the research object, the key technology of deformation monitoring, early warning and safety control of hydraulic tunnels in extremely fractured rock mass is systematically studied by theoretical research, on-site monitoring and numerical computation, the characteristics of the surrounding rock of hydraulic tunnels and stability of the import and export slopes are investigated, and the safety coefficient of the side slopes and danger of slope rockfall are evaluated under multiple conditions, and the stress-strain characteristics of the surrounding rock during excavation of the tunnels and the sides of the side slopes under the condition of extremely fractured rock mass are simulated; On this basis, a monitoring system for hydraulic tunnels and slopes in extremely fractured rock mass is constructed, and an index system for judging the risk of surrounding rock stability is established; finally, an intelligent control system for underground cavern group construction based on BIM is constructed, and a platform for the safety and intelligent control of hydraulic tunnels is set up. The results show that the system improves the accuracy of construction risk identification of hydraulic tunnels in extremely fractured rock mass, realizes comprehensive and efficient real-time monitoring of project status, and provides a scientific basis for safety control of tunnels and slopes.

The use of flip bucket with small slope in aeration facilities along high-velocity flood discharging tunnels can effectively improve the flow conditions within tunnels, but it is difficult to guarantee the aeration effect under large variations of head. Based on the Kashi Hydropower Station, this paper adopts a hydraulic model test to study the hydraulic characteristics of the aeration facilities in flood discharging tunnel under various heads, and analyzes the adaptability of the flip bucket with small slope configuration. The study shows that when the head is 70m or above, the cavity of the flip bucket with small slope without backwater, and has good aeration effect; when the water head is between 25m and 70m, there is varying degrees of backwater in the air cavity, and the aeration effect slightly decreases with the decrease of head. The average reduction of effective air cavity length, ventilation hole airflow, and aeration concentration are 20.4%, 13.4%, and 12.1% respectively, indicating that the aeration facilities with flip bucket with small slope have a wide range of water head adaptability; when the head is below 25m, the aeration effect is significantly reduced, and even the entire cavity is filled with backwater, without aeration mitigation cavitation effect.

The offshore wind power gradually develops towards the direction of far-reaching sea and large capacity, and the offshore wind power DC transmission system based on diode rectifier unit has a great development prospect, and its main circuit parameter design is an important part of the HVDC engineering design. Combined with the basic principle of wind power system and converter station, the working characteristics of offshore wind power DC transmission system based on diode rectifier unit are analyzed. For the important equipment, such as converter transformer, smoothing reactor and AC filter, the calculation formulas of main circuit parameters are derived, and the complete design idea and calculation process of main circuit parameters are given. Lastly, the parameters designed are verified by PSCAD/EMTDC simulation which can provide reference for the future design of offshore wind power DC transmission system based on diode rectifier unit.

The clearance flow channel (CFC) of pump-turbine is a thin cavity composed of a runner and head cover or bottom ring, but excessive pressure pulsation in a flat CFC is easy to cause the head cover excitation. At present, there are insufficient studies on the flow patterns, and pressure pulsations in CFC. In this paper, the 3D CFD numerical simulation method was used to reveal the flow patterns, and pressure pulsations in the CFC of a low specific speed pump-turbine under rotational stall condition. The results showed that the stall vortexes rotated in the vaneless region of the main flow channel (MFC) when the rotating stall occurred in the pump mode; while that rotated in the runner flow channels, causing circumferentially imbalanced pressure at the runner inlet, as well as a low-frequency and high-amplitude pulsation in MFC. In CFC, uneven pressure distribution in the external cavity was formed when the clearance inlet pressure was unbalanced in the circumferential direction in turbine braking mode. The pulsation generated by the rotating stall in the MFC could be transmitted to the CFC, but the pulsation amplitude dropped sharply at the clearance inlet position, then increased first and ultimately decreased inward along the clearance flow channel. This study provides a reference for the study of hydraulic excitation of the head cover.

With the continuous deepening of China’s reform and opening-up, the coordinated development of environmental protection and economic development has become the focus of social attention. As a key new energy technology, pumped storage power stations have functions such as peak power regulation and energy storage, and play an important role in new energy construction. However, its application in China is still in its infancy and lags behind the international advanced level. This paper uses the methods of literature review and practical experience induction to conduct a detailed analysis of the technical issues in the construction of pumped storage power stations. Through an in-depth discussion of the development status of China’s pumped storage power stations, as well as technical problems and governance measures that may arise during their construction, we will provide support for promoting ecological environmental protection, responding to the demand for new energy construction, and creating a green-friendly construction environment. This paper focuses on the technical difficulties encountered during the construction process and proposes corresponding management measures. At the same time, an in-depth analysis of the challenges faced by pumped hydro storage technology and construction was conducted. Through research, it is found that the development of pumped storage power stations in China has made some progress, but there are still some necessary technical challenges. In response to these problems, a series of effective governance measures are proposed, and future development prospects are forecast. Comprehensive research results show that pumped storage power stations occupy an important position and have great potential in China’s new energy construction. Through scientific planning and effective management, problems that may arise during their construction and operation can be overcome, and their wider application in China can be promoted, making positive contributions to ecological environmental protection and sustainable development.

Focus on the Carbon Peaking and Carbon Neutrality Goals, new energy such as solar and wind power generation developed rapidly. In 2023, the installation of solar energy in China exceeded 0.6 Terawatt, accounting for over 20% of the total installed electricity capacity, surpassing hydropower for the first time, becoming the second largest power supply in China. Annual photovoltaic (PV) power generation achieved nearly 583.3 TWh, gradually towards the main power supply. An accurate simulation and prediction of PV power generation is of great significance for the safe and economical operation of the new power systems. In this paper, on 15-min measured irradiance and power generation data of PV plants within one year and the reanalysis meteorological hourly data of ERA5 derived from ECMWF (European Centre for Medium-Range Weather Forecasts), Firstly, we discover the characteristics of PV power generation by analyzing the daily insolation hours and hourly mean power output. Then physical mechanism method is used through radiation model, inclined plane radiation correction model and photoelectric conversion model. PV power output is simulated based on grid-type reanalysis meteorological data. Finally, according to the deviation sequence of simulated and measured power output, a machine learning method extreme gradient boosting (XGBoost) is introduced. After dividing the deviation time series into training set and test set, the training set is applied to learn the patterns to correct the test set. And the test set is fed back to modify the prediction. The results show that by using machine learning method, the determination coefficient (R-squared) of hourly PV power output of a certain station for medium and long-term could reach 0.9, which contribute to improve the accuracy of PV power output generation prediction effectively.

Currently, photovoltaic technology is rapidly advancing, and competition in the industry is becoming increasingly intense. The decreasing prices of silicon wafers and modules have led to a growing demand for photovoltaic installations. The installed capacity and installed share of photovoltaics in power systems are increasing, promoting the transformation of traditional power systems to novel power systems; this maximizes the consumption of new energy as the main task and is supported by source-network-load-storage interactions and multi-energy complementation. Using the Manwan hydro-solar hybrid base as a model, the role of hydro-solar hybrids in source-network-load-storage interactions and multi-energy complementation in novel power systems are discussed.

With the increase in demand for the construction of high proportion new energy base, the power transmission scale of Ultra-High Voltage Direct Current(UHVDC) is growing rapidly, and the characteristics of inter-provincial and inter-regional power transmission are affected by multiple factors, such as the randomness and volatility of new energy in the sending province, the peaks and valleys of the loads, the process of power shortages, and the new time-of use electricity pricing policy in the receiving province. Uncertainty issues are more prominent, and it has changed significantly compared with the traditional UHVDC power transmission methods. It is urgent to study the UHVDC transmission curve planning method in new period. Taking a new energy base in Northwest China as a typical example, a UHVDC power transmission system optimization model is constructed. A UHVDC power transmission curve optimization method that takes into account the power shortages process and the time-of use electricity pricing is proposed, and the Cplex12.6 Solver is used to carry out the 8760 h time series power production simulation. The results show that the obtained 12 curves by the new method can cope with the price-based response demand. Compared with the traditional method, the total cost present value is reduced by RMB 6.10 billion, the power shortage rate is reduced to 0.56%, and the proportion of new energy power is increased to 88.58%. Especially, the power output of pumped storage can track the transmission curve well, and alleviate the requirements for peak regulation flexibility of thermal power units. The power configuration scheme is technically feasible and economical, which verifies the effectiveness of the proposed method. It is suitable for the planning of large-scale UHVDC power transmission schemes. In the meantime, it plays an important role in promoting the level of new energy consumption and helping the low-carbon energy transformation.

With increasing scale of renewable energy integrated into the power system, the power system needs more flexible regulating resources. At present, besides traditional thermal and hydro power plants, pumped hydro storage and battery storage are the most commonly used resources, and they form a wind-thermal-hydro-storage multi-energy complementary system. This paper proposes an optimal scheduling strategy to dispatch the resources in the multi-energy complementary system. First, models of diverse types of resources. i.e., hydro power, pumped hydro storage, and battery storage, are established. Then, a day-ahead optimization scheduling model is proposed for the multi-energy complementary system. Finally, case study is conducted on a revised IEEE 30 node system. Simulation results demonstrate that the proposed method can fully utilize the characteristics of different kinds of power resources to consume renewable energy and enhance the safety and economy of the multi-energy complementary system.

The construction of a hydroelectric project will impact the interaction between surface water and groundwater downstream, potentially disrupting the ecological balance of the downstream wetland water bodies. This study focuses on the effects of the Dongzhuang Reservoir construction on the downstream Jingwei Wetland and conducts numerical modeling calculations of unstable three-dimensional groundwater flow under various operating conditions. It simulates and predicts the variations in water level burial depth at different sections of the wetland protection area and at different distances from the riverbank. The study determines the area of water level changes with and without hydraulic engineering under various conditions, and analyzes the impact of groundwater level changes on vegetation area under different adverse scenarios. The research reveals that the construction of the Dongzhuang Reservoir will have a certain impact on groundwater levels in the Jingwei Wetland. Under the most unfavorable conditions of five consecutive years of drought, the maximum water level drop can reach up to 0.54 m. The range of groundwater burial depth variations under different conditions is between 0.249 km2 to 0.432 km2, with the impact on the vegetation area of the protection area relatively small (all less than 2%). The most extreme adverse effects only occur in individual months, and overall, the operation of the project has a minimal impact on the protection area. This study provides important theoretical support for the harmonious and healthy development of the Dongzhuang hydropower project and the ecological balance of the Jingwei Wetland.

The current assessment of the ecological benefit of reservoirs commonly lacks quantitative calculation of actual ecological distribution. The spatial distribution prediction of vegetation growth generally requires the concurrent application of multiple numerical models, which are complicated and involve numerous parameters. This research comprehensively utilized a surface hydrodynamics numerical model and machine learning method to construct a flow-based vegetation growth prediction model. The ecological impact during the storage period and regulation period after the completion of the Dongzhuang Water Conservancy Hub was calculated and analyzed. The results indicate that the regulation period after the construction of the reservoir has a minor impact on vegetation growth in comparison to pre-construction flow conditions in the normal flow years. The limited extent and magnitude of regional NDVI decline induced by the reservoir storage period will gradually recover after the beginning of reservoir regulation. The formulated vegetation growth prediction model can reflect the relevant influence processes on NDVI to a certain extent and alleviate the complexity of prediction.

This paper starts from the key factors affecting photovoltaic power generation and first studies the lighting characteristics of different regions. It then conducts an analysis of the characteristics of the massive spectral data collected, determines the extraction method of spectral data, and calculates the difference in short-circuit current of photovoltaic modules due to spectral differences for specific regions. This has guiding significance for further research on the differences in the operation of novel and efficient photovoltaic modules in different regions.

China's water conservancy and hydropower enterprises continue to face the challenge of lagging hydropower standards despite being a major player in the construction of water conservancy and hydropower projects. This paper presents a theory for evaluating the social integration process of immigrants in water conservancy and hydropower projects. The theory aims to promote China’s ‘Belt and Road’ strategy, enhance China’s modernization, and establish China’s right to speak. The paper explains the overall framework, process evaluation, and result evaluation of the theory. The evaluation process can be divided into three periods: planning, placement, and later support. The result evaluation is divided into three aspects: environmental adaptation, population development, and cultural integration. Using the Three Gorges Project as an example, this text preliminarily tests the science, rationality, and feasibility of the entire assessment theory. In the future, research on engineering immigration should expand the application scope of the whole process assessment. Sufficient attention should be paid to the problem of social restructuring, and efforts should be made to build an assessment system with Chinese characteristics.

The era of socialism with Chinese characteristics and the century-long unprecedented changes in the world are intertwined and mutually stimulating. With the coordinated promotion of the strategic deployment of achieving carbon peaks and carbon neutrality and the overall layout of ecological civilization construction, the national policy dividend is favorable to hydroelectric power development, and hydroelectric energy development presents huge advantages and development prospects. However, at present, hydropower development is constrained by non-engineering technical issues, especially the resettlement and relocation activities caused by the submergence of reservoirs have become one of the most concerned issues. In the context of China's vigorous promotion of new urbanization, it is worth conducting in-depth research on how to seize this historical opportunity and integrate the resettlement of rural migrants from reservoir projects into the development process of new urbanization. This article takes the basic elements of reservoir resettlement as a starting point, conducts an in-depth analysis of three key elements, and uses this as the basis to construct an urbanization resettlement analysis framework alled “production resettlement-living resettlement-institutional arrangement.” Based on this, it focuses on the core issue of production resettlement, and endeavors to propose an enclave economic model in areas with more developed secondary and tertiary industries. Simultaneously, this model is applied to the “NA” reservoir in Zhejiang, calculating the value of land resources in the reservoir area, proposing specific purchase plans for the resettlement area by cross-township, and analyzing the effects of immigrant resettlement. This study found through empirical research that: 1) By trading submerged resources (land requisition comprehensive area price) in the reservoir area plus non-submerged resources (land transfer and custody price) for industrial land, the preferred purchase solution for industrial land is 1298.83 acres of industrial land plus 0 acres of standard factories, while the preferred purchase solution for standard factory is 0 acres of industrial land plus 116.80 acres of standard factories. By trading submerged resource in the reservoir area plus non-submerged resources (land requisition comprehensive area price) for industrial land, the preferred purchase solution for industrial land is 3,827.03 acres of industrial land plus 0 acres of standard factories, while the preferred purchase solution for standard factory is 0 acres of industrial land plus 344.15 acres of standard factories. 2) The submerged resources (land requisition comprehensive area price) and non-submerged resources (land transfer and custody price) in the reservoir area can be purchased with 115.03 to 122.02 mu of standard factories. The per capita annual rental income in the base year is 5879.02 to 6236.27 yuan, and the per capita annual rental income in the planning year is 5991.81 to 6355.91 yuan. The submerged resources and non-submerged resources (land requisition comprehensive area price) in the reservoir area can be purchased with 338.93 to 359.52 mu of standard factories. The per capita annual rental income in the base year is 173,222.3 to 183,744.5 yuan, and the per capita annual rental income in the planning year is 176,545.7 to 187,270.8 yuan. Accordingly, whether using the calculation method of submerged resources (land requisition comprehensive area price) and non-submerged resources (land transfer and custody price) or submerged resources and non-submerged resources (land requisition comprehensive area price), the per capita rental income of immigrants exceeds the per capita agricultural net income of immigrants from the base year to the planning year. Therefore, the enclave economic model has a great promoting effect on the future production recovery and development of immigrants and can fully ensure the improvement of their production income level and sustainable development after resettlement.

Reservoir scheduling is an important and effective measure to optimize water resource allocation. It effectively mitigates issues such as regional water scarcity and ecological degradation and plays a crucial role in supporting sustainable water resource development. The Yellow River has experienced severe water scarcity, and the increasing human water demand in recent decades has significantly reduced the river’s ecological flow, causing significant ecological damage. Balancing the benefits of ecological flow, hydropower generation, and water supply and selecting appropriate ecological flow levels for different hydrological years is a major challenge for reservoir operators. This paper aims to integrate ecological flow into reservoir management standards by investigating the competition and reasonable coexistence between reservoir benefits and ecology in water-scarce regions. A multiobjective reservoir ecology management model was proposed to study the effects of different ecological flow levels on hydropower generation, water supply, and storage. Using the LYX and LJX reservoirs as a case study, the results illustrate the applicability and effectiveness of the model in balancing conflicts among hydropower generation, water supply, storage, and ecology in multi-objective reservoir management. Under basic ecological flow management, hydropower generation and water supply benefits are fully met in typical years, with a significant increase in hydropower generation. Under suitable ecological flow management, hydropower generation and water supply benefits are met only in abundant water years. Considering the impact of storage on management, in typical normal and dry years, under suitable flow management standards, the hydropower generation and water supply guarantee rate targets are approximately 12.49 billion kWh, 96.71%, and 8.22 billion kWh, 96.71%, respectively, promoting efficient water resource utilization and enhancing future drought resilience.

Hydraulic engineering projects provide essential functions and services, including flood regulation, hydroelectric power generation, and agricultural irrigation. Additionally, they offer benefits such as navigation, water purification, recreational opportunities, and biodiversity maintenance for upstream and downstream regions. To comprehensively describe the overall functioning of hydraulic engineering as an ecosystem, evaluate its contributions to human well-being, assess its support for economic and social development, and understand its ecological linkages across regions, it is essential to scientifically account for the comprehensive benefits of these projects. This study uses the Lianhu Reservoir in Lishui, Zhejiang Province, as a case study to assess the Gross Ecosystem Product (GEP) before and after the construction of the hydraulic engineering project. The results show that before the construction of the Lianhu Reservoir (in 2021), the total GEP within the construction area was 206 million yuan. The value of regulating services was 197 million yuan, accounting for 95.6% of the total GEP, with climate regulation and flood control contributing 175 million yuan and 21 million yuan, respectively. The value of provisioning services was 9.06 million yuan, accounting for 4.4% of the total GEP. After the construction of the Lianhu Reservoir, the total GEP within the construction area increased to 1.42 billion yuan. The value of regulating services was 781 million yuan, accounting for 55.0% of the total GEP, with flood control and climate regulation contributing 480 million yuan and 297 million yuan, respectively. The value of cultural services was 498 million yuan, accounting for 35.1% of the total GEP, while the value of provisioning services was 141 million yuan, accounting for 9.9% of the total GEP. The results indicate that compared to the pre-construction period, the GEP after the construction of the Lianhu Reservoir increased by 1.21 billion yuan, representing a 588% increase. Except for the services of agricultural product supply, carbon sequestration and oxygen release, and air purification, all other service items were enhanced.

Human-induced climate change has affected weather and extreme climate events, the Three Gorges Hydropower Project is the largest hydropower project in the world, which must inevitably have some impacts on the regional climate and extreme climate. Based on the data of precipitation, temperature, sunshine hours, relative humidity, minimum temperature and maximum temperature of 14 meteorological stations in the study area for 59 years from 1961 to 2019, this paper adopts the climate tendency rate, Mann-Kendall test, ordered clustering method, Kriging difference method to analyze the climate change trend and spatial differentiation characteristics before and after the impoundment of the Three Gorges Reservoir. The results indicated that the impact on precipitation is weak, there is no significant trends; sunshine hours and relative humidity all showed a significant decreasing trend at 11 stations. However, Except Gaoping, Badong, Enshi and Laifeng, the temperature of the other 10 stations has changed significantly rise trend from a cooling trend to a warming trend. The Three Gorges Reservoir has a slowing effect on the rise of minimum temperature at Wanyuan, Badong, Wufeng, Yichang, Jingzhou, Wanzhou, Shapingba, Laifeng and Yibing, the impact on the ecosystem is beneficial. The increase of maximum temperature at 13 stations except Yichang will inevitably change the regional ecosystem. The abrupt changes of temperature, relative humidity and maximum temperature all occurred after impoundment of the Three Gorges Reservoir. After the impoundment of the Three Gorges Dam, the precipitation variability increased in the west and decreased in the east; North-central temperatures rise more; The decrease range in the east is greater than that in the west; Relative humidity in the west decreased more than that in the east. The temporal and spatial changes of lacal climate will inevitably have a certain impact on the local ecosystem.

The mountainous terrain in the southwest region is characterized by significant topographic relief and abundant rainfall. When constructing new energy infrastructure such as booster stations in mountainous areas, it is extremely easy to induce landslide instability due to the excavation of mountain slopes. This article takes the Wangmo landslide in the southwestern region of Guizhou Province as the research object, uses multi-rotor drones as platforms, and utilizes techniques such as ground-based photogrammetry and close-range photogrammetry to detect and obtain relevant parameters such as the shape, deformation and damage characteristics, and zoning of the Wangmo landslide. The specific application methods and application effects of fine reconstruction of drones in landslide hazard detection and management are elaborated and discussed. The conclusions are as follows: Compared with traditional orthophotography, the high-definition image data obtained through fine reconstruction of ground-based photogrammetry and close-range photogrammetry generates more comprehensive orthophotographs and 3D model textures with higher resolution. Using the orthophotographs and 3D models produced by fine reconstruction, the structural surface combination, surface crack development, and landslide deformation zone are interpreted, and the formation mechanism of the landslide is determined in conjunction with ground surveys, providing a data foundation for prevention and control design. UAV aerial survey has the characteristics of short cycle, flexibility, and strong emergency response, and has high promotion value in landslide hazard investigation of booster stations.

The purpose of this study is to conduct a preliminary study on the flexural deformation of photovoltaic modules in low-temperature environments. By analyzing the characteristics and influencing mechanisms of flexural deformation, theoretical basis and technical guidance are provided for the design, manufacturing, and application of photovoltaic modules, and the performance and reliability of photovoltaic modules in low-temperature environments are improved. We have developed a warping deformation testing plan for photovoltaic modules under different temperature environments using a true type test method, and measured and analyzed the warping deformation of photovoltaic modules under different temperature environments. The results indicate that low-temperature environment is the main cause of deflection deformation of photovoltaic modules, and the strength of the frame structure and materials also have a certain impact on the degree of deformation. This study can provide assurance for the long-term operation of photovoltaic modules, reduce maintenance costs and failure rates of photovoltaic systems.

The long-sequence hourly photovoltaic power simulation sequence is an important reference information in the stage of power station planning, designing and dispatching operation. Based on the ERA5 reanalysis data, this paper adopts the tilted plane radiation model and the photoelectric conversion model to construct a photovoltaic power physical simulation model, and conducts hourly power simulation study for a total of 23 years from 2000 to 2022 for 30 existing photovoltaic power stations in China, and analyzes the simulation effect and the interannual volatility of power generation capacity in different temporal and spatial ranges. The results show that: on different time scales, the power simulation results are different, and the long time scale is better than the short time scale. The root mean square errors of the monthly average, daily average and hourly scales are 0.89–20.8, 0.43–9.61, and 0.3–3.42 respectively; in different spatial ranges, the power simulation results are also different, and the power stations with relatively low simulation effect are mainly distributed in the western region with smaller longitude; there are great differences in the interannual power generation capacity volatility of each power station, and the volatility between years of the power stations at low latitudes is relatively large. In general, the power simulation result of the ERA5 reanalysis data can better reflect the actual operation law of the power station, and carrying out long-sequence power simulation through the ERA5 reanalysis data can provide relatively reliable data support for the planning and operation of the power station.

Today, the effects of climate change are increasingly evident. In the southern region of Brazil, significant impacts have been observed, such as the peak flows in November 2023, when a state of emergency was declared in the areas of the municipalities of Rio das Antas, Rio Grande do Sul, due to the impacts of heavy rainfall in the region. Such events may become more frequent in the coming years, so that the forecasting of hydroelectric inflows is necessary to plan the operation of the plants and to carry out preventive actions to deal with extreme events. The Ceran complex is located on the Antas River and consists of three hydroelectric plants, the Castro Alves, Monte Claro and Quartorze de Julho plants, and with a view to the sustainable operation of the projects in order to make conscious use of water resources, optimize operations and minimize the impact on the well-being of local populations, it has been studied and applied that rainfall-runoff models to forecast the inflows to the projects on the Antas River cascade. Rainfall-runoff models are essential for predicting extreme flows and taking preventive action, providing the operations center and the team involved with information for prior decision-making and, if necessary, evacuation of operators and potentially affected communities. In view of the above, this paper will apply the MEL model to convert rainfall into flow and compare the predicted results with the observed ones.

The design of storage pressure is an indispensable step for reusing the existing hydropower tunnels into compressed air storage cavern, which directly affects the safety and economy of the plant. To design appropriate pressure, firstly the three anti lifting theoretical models are adopted to establish the analytical ultimate pressure methods in this paper and the ultimate pressure obtained under different parameters are compraed and anyasided. Based on multi-layer thick-walled cylinder theory, an improved calculation method for the ultimate pressure is proposed. Then parameter sensitivity analysis are conducted to reveal the key coefficient affecting the ultimate pressure corresponding to the model. Finallly, the proposed method is applied in the traffic tunnel of Baihetan Hydropower Station as an example.The results show that the straight failure plane (SFP) model is relatively conservative, resulting in lower ultimate pressure. The shear resistance of the conical failure surface surface will increase the ultimate pressure. The newly proposed model takes into account the influence of structures, and obtains a more reasonable ultimate pressure by limiting the tension stress of the steel lining. The surrounding rock's elastic modulus and burial depth exert the most significant influence on the ultimate pressure. In contrast, the effects of tunnel radius, steel grade, and concrete lining thickness are of moderate importance. The impact of steel lining thickness, concrete grade, Poisson's ratio of the surrounding rock, and surrounding rock density on the ultimate pressure is comparatively minor. The ultimate pressure of the Baihetan traffic tunnel by this method is 23.6 MPa. This study is of great significance for the renovation of compressed air storage in hydropower tunnles.

During the water level design process of lock with water saving basins (WSBs), it's an important part that to determine the water level and head of the WSB, and there are many influencing factors in the process. This paper derives and establishes calculation formulas for evaluating the water level and the water head of the single-step lock with WSBs, which integrates the total head of ship lock, the upper and lower stream water level variation, the number of the WSB levels and area of the WSB, and the remaining head. On the basis of formulas, the influence of factors such as the upper and lower stream water level variation, the number of the WSB levels and the area of the WSB on the water level and the water head of the WSB are analyzed, and the control conditions of the integrated and decentralized arrangement of WSBs and water-saving rates of replenishment and overflow operations are calculated. The results show that when total head of the lock is constant, head of the WSB decreases with the increase of the area of the WSB and the number of the WSB levels, and the increase of the number of the WSB levels is greater than the increase of the area of the WSB; when the number of levels and area of the WSB increase to a certain level, the reduction of the water head of the WSB becomes slow; the highest and lowest water levels of the WSB are controlled by the maximum variation of the downstream and upstream water levels respectively. Finally, the water levels and the water head of difference WSB schemes are calculated and compared in a 60m single-level ship lock, and a reasonable water level scheme of WSB is proposed.

Escalating energy demands and dramatic changes in global climate present a formidable challenge. As a clean, renewable, and unexploited large-scale energy source, ocean wave energy has attracted research attentions all over the world. Although the existing theoretical technologies of wave energy power generation are emerging rapidly, few of them can be applied to massive practical deployment. The current achievements of wave energy resources are reviewed in this paper; various forms and energy transmission modes of oscillating buoy wave energy converters are summarized, and their characteristics and scope of application are detailed; the different array arrangement and benefits of the oscillating buoy wave energy converter are summarized; the directions for future oscillating buoy device development are outlined. Particularly, enormous amount of wave energy from far offshores will be exploited through using advanced and sophisticated equipment and technology, the oscillating buoy energy capture method and more direct and efficient direct-drive power generation devices will be the main choice for wave energy development in the future; to optimize the selection, size, and array layout of oscillating buoy wave energy converter can effectively improve the energy conversion efficiency and lower the levelized cost.

The Power Industrial Internet serves as an essential platform for the digital transformation of the electric power industry, during its implementation, the integration of Information Technology (IT) and Operational Technology (OT) in power production and maintenance has posed significant challenges, necessitating the development of intelligent equipment based on Cyber-Physical Systems (CPS) to bridge this gap. Microcomputer platforms are well-established and reliable systems capable of running various complex algorithms. However, traditional microcomputer-based protection devices face limitations such as firmware programming, limited types of signal sampling, and insufficient data transmission capabilities. In the current era of digital transformation, there is an urgent need for intelligent devices and smart terminals that can overcome these shortcomings through cloud-edge collaboration to assist the digital transformation of the power industry, continuously creating effective applications that enhance quality and efficiency, and fostering new productive forces. This article starts from the strategic orientation of industrial development, the problem orientation of digital transformation, and the demand orientation for quality improvement and efficiency enhancement. It focuses on the key issues in the advancement of the industrial internet, proposes solutions based on microcomputer platforms, and explores new directions in the development of intelligent and digital transformation in the field of relay protection specialization.

Ionic liquids have been considered as promising electrolytes for supercapacitors due to the wide electrochemical stability window. However, water molecules inevitably damage the electrochemical properties of ionic liquids due to the hygroscopic property. This paper reveals the effect of water molecules on the interfacial structure and energy storage performance of ionic liquids using the atomistic simulations. Unlike neat ionic liquids, the Helmholtz region for humid ionic liquids is mainly composed of BMI cations and water molecules. Importantly, water molecules primarily accumulate in the buffer region between BMI cation and graphene electrode, especially at the high negative charges, which is the crucial factor to induce the hydrogen evolution reactions for the decreased electrochemical stability window. More interestingly, the dielectric properties of water molecules in the buffer layer are beneficial for lowering the electric potentials for higher capacitive performance. The differential capacitance of [BMI+][BF4−]/H2O electrolyte exhibits a bell-shaped curve with a maximum value of ~5.0 F/cm2 at 0.75 V. The revealed insights are important for understanding the water effect in ionic liquid-based supercapacitor energy storage.