Accurate inversion of dam mechanical parameters based on dam monitoring data is crucial to ensure the safe and stable operation of the dam. This paper presented an arch dam parameter inversion model based on radial basis function (RBF) network and Artificial Gorilla Troops Optimizer (GTO). Firstly, the RBF surrogate model was used to replace the finite element model to discuss the relationship between the material parameters and the displacement response of the monitoring point. The sampling data of the RBF surrogate model was generated by the efficient Latin hypercube sampling technology. Secondly, the GTO intelligent optimization algorithm was adopted to minimize the objective function of material parameter identification. The analysis results of engineering examples show that the RBF-GTO model can achieve high-precision parameter inversion analysis of concrete super-high arch dams while reducing the calculation cost.

The calculation of maximum power supply capacity is an important issue in optimal operation of UHV complex large power grid. With the large-scale access of high-proportion renewable energy to the power grid, the problem of power and energy balance is becoming more and more prominent. Considering the stability spinning constraint, coupling section constraint and unit regulation capacity constraint, the calculation problem of maximum power supply capacity presents high-dimensional characteristics, which is difficult to model and solve. According to the limitation of transmission section and the characteristics of partition operation of UHV complex large power grid, an optimal dispatching model of maximum power supply capacity of UHV complex large power grid considering section coupling control was established. Then, the Simplex method (SM), Interior Point method (IP), Simulated Annealing (SA), Beluga Whale Optimization (BWO) and Artificial bee colony algorithm (ABC) were applied to solve the model respectively, and the maximum power supply capacity of the large power grid in the next 15 minutes was calculated. The coordinated optimization scheme of various types of power supply and reserve was proposed. Finally, a regional power grid was taken as an example to verify the model and the solution method. The simulation results show that because of the large scale of the power system and the complex coupling relationship between the sections, the heuristic intelligent optimization algorithm has a long running time, slow convergence speed and low search accuracy. The interior point method converges rapidly, has strong robustness, is insensitive to the selection of initial values, has better stability and computational efficiency, which can provide effective and practical support for power supply and power balance of complex UHV power.

In response to the evident phenomena of flow separation and backflow, low efficiency, and increased cavitation in the tailrace conduit of the Deneng Xiangjiang Hydropower Station after expansion, computational fluid dynamics (CFD) analysis was employed. Two methods, namely, modifying the shape of the tailrace conduit or replacing the runner, were proposed to improve the flow pattern within the tailrace conduit. Research has demonstrated the effectiveness of both methods, which can provide reference for similar projects.

To ensure the structural safety of the double row steel sheet pile cofferdam and control its water use area, the single-factor sensitivity analysis method was carried out to study the impact of various items on the deformation of cofferdam, and the PLAXIS software was used to implement the 2D and 3D finite element calculation. The results show that the elevation and tension of tie rod, and the specification of steel sheet pile have little impact on the deformation of cofferdam in soil; Compared with the width of the cofferdam itself, the deformation of cofferdam is more affected by the width of inner foot, so the width of the inner foot should be increased as much as possible; The depth of the outer sheet pile has no obvious impact on the deformation of the cofferdam, so that it can be reduced appropriately, and the depth of the inner sheet pile can be increased; The effect of the transverse structure on controlling the deformation of the cofferdam is not obvious, and other measures can be taken to strengthen the connection between the inner and outer sheet pile. The research ideas and calculation results can provide reference for structural design optimization of steel cofferdam in similar projects.

The distribution of measured operating data of hydraulic turbines is non-structural and uneven density. The moving least squares method was used to fit the measured operating parameters to obtain the spatial characteristic surface of the water turbine, which can reflect the local characteristics of data surface and avoid the distortion caused by the differences of data distribution density. The Riyadh criteria was used to perform preliminary data filtering. The support radius was adaptively determined by local fitting across different ranges of discrete sample points. The robust moving least square surface reconstruction model was established combined with the Mahalanobis distance denoising method. Compared with the least squares method, the example calculation results show that the moving least squares method fits the operating characteristics of hydraulic turbines with higher accuracy and supplements the local data effectively. The result can reflect the operating characteristics of hydraulic turbines authenticity, which provides a reference for correcting the operating characteristic curve given by the turbine manufacturer.

In response to the complex mechanism of runoff yield and concentration, insufficient groundwater monitoring data, and low accuracy of runoff prediction in Karst areas, a similarity prediction method that integrates physical mechanisms and data-driven approaches has been proposed. The optimal combination prediction scheme has been established for different flow magnitudes, prediction factors, and preceding affected lag-time, which can achieve adaptive matching and intelligent switching of multiple modes under different water and rain conditions. It can generate interpretable runoff prediction results. This method is applied to the runoff prediction of Longtan Hydropower Station. The results indicate that this method improves the accuracy and effective prediction period of runoff in Karst areas, which has scientific significance and practical value for ensuring the scientific scheduling and safe operation of large power plants.

Under the background of building a new-type power systems, the hydro-thermal-wind-solar-storage system with a high proportion of new energy has become the main research object of power system planning. It is necessary to perform high-frequency iterative calculations on the long-term supply-demand balance of the hydro-thermal-wind-solarstorage system to achieve quantitative analysis of sensitive boundaries, which puts forward higher requirements for the calculation efficiency of the analysis method. Considering the working characteristics of various power sources and the output probability characteristics of new energy sources, this paper proposed a heuristic unit commitment algorithm based on operating rules, which realizes the daily determination of the unit start-up mode throughout the year, and further constructed a supply-demand balance model. Finally, a case study based on a regional power grid example proved that the proposed model and method were feasible and effective, which provides reference for analyzing long-term supply-demand balance of the hydro-thermal-wind-solar-storage system.

The characteristics and distribution of in-situ stress field have an important influence on the stability and engineering design of the surrounding rock of underground power house. According to the deep surface drilling hole and engineering geological conditions of the underground power house of a pumped storage power station, a three-dimensional numerical analysis model was established, and the inversion reconstruction of the initial in-situ stress field was realized through multiple linear regression analysis. The results show that the maximum horizontal principal stress measured in deep holes is 6.7-17.6 MPa. The magnitude and direction of the inversion model are in good agreement with the measured value, and the horizontal stress in the underground workshop area is dominant, and the maximum horizontal principal stress is 16.2-17.4 MPa. The maximum principal stress azimuth of the stress field in the plant area is less than 30°, and the stress distribution and azimuth angle meet the design requirements. The research results provide a reference for similar large-scale underground projects.

The high penetration of distributed renewable energy aggravates the power fluctuation and uncertainty of distribution network. In this paper, a two-stage optimal operation strategy of distribution network based on multi-objective reduction and multi-step reconfiguration was proposed. In the day-ahead stage, multiple operational flexibility index models of voltage deviation, power loss, total operating cost, net load peak-valley difference and net load coefficient were constructed. On the basis of the model, a multi-flexibility index dimension reduction method based on target correlation was proposed, which aims to balance the relationship between various indicators, reduce the number of targets and improve computational efficiency. In the intraday phase, a distribution network reconfiguration method based on multi-step switch sequence exchange was proposed by cooperatively controlling the sectionalizing switches and tie switches, which fully exploits the available flexibility resources of the system. Finally, the simulation of arithmetic cases based on the IEEE-33 node system, the IEEE-84 node system, the IEEE-119 node system and the IEEE-136 node system were carried out, and the results show the effectiveness of the proposed two-stage distribution network flexibility enhancement strategy.

The deicing effect of wind turbine blades was tested and analyzed based on the air-thermal method. The thermal conductivity efficiency of the paving structure and the influence of blower speed (or frequency) on the deicing efficiency were mainly considered. Firstly, the blade structure and layering structure were introduced, and the thermal conductivity was estimated by measuring the thickness of the layering structure. According to the ice-covered position of the blade in winter, the rationality of the thermal conductivity distribution of the blade during air-thermal deicing was verified. After that, the field blade deicing test was carried out by changing the speed (or frequency) of the blower. The test results reveal the root cause of the unbalanced deicing phenomenon in the process of wind turbine blade deicing by air thermal deicing system. It shows that the higher the speed (or frequency) of the blower is, the better the deicing equilibrium of the blade surface and the more significant the deicing effect are under the premise of ensuring the temperature stability of the outlet of the ventilation pipe. In addition, with the use of larger blower frequency, the internal circulation of the blade was enhanced, and the reasonable setting of the internal circulation structure of the blade can effectively improve the de-icing efficiency and reduce the de-icing consumption time.