After a high proportion of new energy is connected to the grid, the grid security and stability are significantly increased by multiple uncertainties. In order to quickly form a power adjustment plan to maintain the source-gridload dynamic balance under the scenario of power gap caused by large fluctuations of new energy, it is urgent to quantitatively evaluate the maximum power supply capacity of the grid. In this paper, the maximum power supply capacity and the minimum section margin of important sections are taken as the optimization objective functions, and the maximum power supply capacity assessment scenario of provincial power grids is modeled with power balance, slice reserve capacity, and section margin as the constraints, and the multi-stage constrained multi-objective evolution (CMOEA-MS) algorithm and the fast non-dominated ranking genetic algorithm NSGA-Ⅱ with elite strategy are used to solve the model, respectively. The quality of the solution sets of the two algorithms is evaluated in term of three indexes of convergence, uniformity and extensiveness of the solution sets. The simulation results of example show that the CMOEA-MS model has larger super volume values and better performance in solving the model, and can effectively improve the maximum power supply capacity of the provincial grid.

The downstream surge chamber of a certain pumped storage power station adopts impedance with upper chamber layout. The tailrace tunnel is connected with the connecting pipe through right angle bifurcated pipe and bend. The layout type is special and the water flow conditions are complex. In order to study its hydraulic characteristics, a three-dimensional flow field mathematical model of the connecting pipe at the bottom of the surge chamber was established, and the variation law of hydraulic characteristics under different diversion ratio and confluence ratio was studied. The results show that for the resistance loss of surge chamber with complex bottom flow, the three-dimensional numerical simulation can achieve better simulation effect, and the calculation results are in good agreement with the theoretical analysis results. Because the elbow at the bottom of the surge chamber, the sudden expansion and contraction between the connecting pipe and the big well will cause additional hydraulic losses, its head loss coefficient is greater than that of the conventional impedance surge chamber, and the flow coefficient is smaller than that of the separate impedance hole.

Aiming at the shortcomings of low efficiency and time-consuming when using the ANSYS parametric design language (APDL) to carry out the three-dimensional finite element design of the gate structure, this paper proposed a APDL design-analysis program based on VB, and performed nephogram results on a certain project. The results show that the program can improve the design and analysis efficiency of steel arch gate, and programmers can flexibly debug related to practical project cases, so that the designed steel arch gate can meet the needs of project construction.

At present, BIM technology has been applied in some majors of water conservancy and hydropower engineering projects, but it has not yet formed the overall collaborative design and systematic digitalization of the whole process. This paper aims at the characteristics of the Jinchuan Hydropower Station project with high positioning, deep covering of the face rockfill dam, complex geological conditions of the diversion power generation system and the actual needs of the project. The whole process of 3D BIM design has been implemented, the standard system has been clarified, and digital surveys have been carried out for all majors and all stages. This research realizes BIM collaborative design, application of 3D design results, dynamic update, and the whole process of lightweight digital handover on web and mobile terminals, establishes a digital achievement management platform, and lays a data foundation for smart engineering and digital power plants. At the same time, the "BIM+" multi-source data management has been carried out to realize the functions of BIM-based geological forecasting, construction progress management, dynamic feedback analysis, and intelligent management of safety monitoring, which provides a platform basis and theoretical guarantee for safety risk control and lean construction management. This research provides a reference for the whole-process, all-professional overall collaborative design and systematic digital application in other hydropower projects in the future.

The supersaturated total dissolved gas (TDG) is mainly caused by the discharge of high dam spillway, excess oxygen production of plant photosynthesis and sharp increase in water temperature, which may directly lead to fish and aquatic organisms suffering from gas bubble disease (GBD) or even death. In order to explore the measures to mitigate the adverse effects of supersaturated TDG, under different aeration conditions, the swirl mixing aeration mode has an obvious effect on the release of supersaturated TDG, its effect is slightly stronger than that of pinhole aeration method, and the aeration rate has the greatest impact on the mass transfer coefficient of supersaturated TDG, followed by the aeration depth, and the aeration diameter is the smallest. The relationship between supersaturated TDG mass transfer coefficient and aeration rate, aeration diameter and aeration depth is obtained, respectively. The average error is within ±6.25%. The research results provide a data basis for mitigating the adverse effects of supersaturated TDG.

Scientific assessment of the hydrological regime is an important part of the assessment of the health of the river ecological environment. The IHA indicators were used to quantitatively evaluate the change of hydrological indicators of Gaobazhou Station during the construction period and operation period of water conservancy projects in the Qingjiang River Basin. On the basis of analyzing the change law of five different IHA indicators, the overall hydrological situation change of Qingjiang River was analyzed by selecting three different RVA methods, which include the Nemero index method, the RVA method based on the European distance method and the RVA method considering the comprehensive weight. It shows that the results of the analysis of the hydrological situation in the Qingjiang River Basin by the three methods during the construction period and the comprehensive utilization period are moderate and highly changed, respectively, and the hydrological situation change in the Qingjiang River Basin has an increasing trend. The evaluation results of the RVA method considering comprehensive weights are similar to the previous two methods and are reasonable, which can better reflect the changes in the river hydrological situation after the construction of the water conservancy project in the Qingjiang River Basin.

In order to deeply understand the impact of the alteration of different opening angles of the two stage flap valves on outflow, a two- stage flap valve of a certain pumping station was taken as an example. Choosing four opening angle schemes widely used in practical projects, the three-dimensional flow pattern behind the two stage flap valve under different flow rates was simulated. The influence of flow streamline, velocity uniformity and hydraulic loss in culvert on the flow pattern was analyzed. The results show that the resistance loss coefficient along the outlet culvert is inversely correlated with the opening angle, to be specific the larger the opening angle of the flap valve, the less the hydraulic loss of the water flow in the outlet culvert pipe, and disparity degree becomes more obvious with the increase of the flow rate. When the flow rate is 2 m³/s, the hydraulic loss of the outlet culvert pipe in scheme 4 decreases by 49.6% compared to that of scheme 1; When the flow rate is 16 m³/s, the hydraulic loss of the outlet culvert pipe in scheme 4 decreases by 79.1% compared to that of scheme 1. To conclude, the larger the opening angle of the flap valve, the better the flow pattern in the culvert and when the flap valve is opened to 46°for the upper flap valve and 64°for the lower flap valve in scheme 3, the flow pattern in the culvert has tended to a better state.

As a widely used function in hydrologic frequency and flood computation, the Gamma function has many calculation methods, and the scope of application and computation accuracy also vary. In order to explore a high-precision Gamma function computation method suitable for hydrological computation, different Gamma function asymptotic expansion formulas such as Stirling series and its derived approximation formula are used for computation and analysis. Comparing the accuracy and application range of various methods, the results show that the piecewise polynomial method has the smallest truncation error and the highest accuracy; The second is the Ramanujan asymptotic expansion and the Stirling first tetranomial. The recommendatory high-precision Gamma function computation method can effectively improve the computation accuracy of hydrological results, which can provide fast and accurate results for the planning and design of various hydro projects to determine project scale and management decisions.

The bedload sediment transport in the compound channel is affected by the presence of emergent rigid vegetation, and there were few studies available on this topic. The laboratory experiments and theoretical analysis were used to investigate the effect of emergent rigid vegetation in parallel arrangement on the threshold Shields number and the bedload transport intensity. The results show that the presence of emergent rigid vegetation in parallel arrangement increased the threshold Shields Number by 97.2%, and the bedload transport intensity reduced by more than 80%. The modified Engelund Formula that was applicable to the emergent rigid vegetation in parallel arrangement conditions was developed to calculate the bedload transport intensity. The formula was shown to have a high accuracy by applying it to the other studies.

The purpose of the paper is to explore connection mechanism between interval time and pressure at draft tube inlet in successive load shedding case. Based on transient flow theory and method of characteristics, numerical simulation calculation of transition process in the successive load shedding case for pumped storage power station with layout of two turbines and one tunnel was carried out. The relationship between flow rate, running track of turbines and minimum pressure at draft tube inlet was analyzed. The result shows that there is a certain most unfavorable interval time making the time-domain asynchronous degree of first wave flow rate in two turbines maximized and the pressure at draft tube inlet is the minimum. At the same time, running track point of the first load shedding turbine is near the upper bending point in the inverse S-region of characteristic curve and running track point of the last one is near the lower bending point. The conclusion can provide a reference for calculation of extreme value of pressure at draft tube inlet in the pumped storage power station.