The ultra-short-term reservoir water balance simulation of channel-type reservoirs is the key to the operation of the reservoir, but the results easily appear sawtooth oscillation. The calculation error is due to the fluctuation of the water level in front of the dam by extending the simulation time scale. Among the factors that cause the fluctuation of the water level in front of the dam, taking the load change as an example, the calculation error of water balance caused by the load change was corrected. An ultra-short-term water balance method for channel-type reservoirs was put forward based on one-dimensional hydrodynamics. The method established a one-dimensional hydrodynamic model of the river-reservoir area, and procured the accurate storage capacity by calculating the average water level instead of the water level in front of the dam, thereby eliminating the jagged error. The calculation results show that the simulation accuracy can be effectively improved after eliminating the influence of load changes. The ultra-short-term water balance method for channel-type reservoirs based on one-dimensional hydrodynamics can eliminate the sawtooth error and achieve high simulation accuracy.

Continued land development around the world has accelerated the construction of impervious surfaces, thereby changing the hydrological cycle of the natural environment itself, resulting in frequent urban waterlogging disasters. Due to its own limitations, the old city not only cannot reasonably utilize rainwater resources, resulting in a waste of rainwater resources, but also is often in the predicament of flooding every time when it rains. Taking the Nandajie area of the old city of Xifeng District in Qingyan City, Gansu Province as an example, the construction effect of different LID measures in each return period was simulated through SWMM modeling. The best LID measures suitable for the study area were selected. The results show that the reduction effect of the combined measures is the best, the reduction rates of the total runoff and the peak runoff are over 68.71% and 68.90%, respectively, the peak time is delayed between 10-15 minutes, and the reduction rate of the overload of the pipe network decreases with the increase of rainfall return period. The research results provide reference for optimization of LID measures in the old urban areas of Northwest China.

In view of the fact that traditional neural network models can hardly make full use of the topological relationship of the backward forward information of dam deformation monitoring time series data, while the bidirectional long short-term memory (BiLSTM) can effectively learn the backward forward information, a combined dam deformation prediction model BES-BiLSTM was proposed based on bald eagle search algorithm optimized bidirectional long short-term memory neural network. Firstly, the bald eagle search algorithm was used to optimize parameters of the model. Secondly, the bidirectional learning feature of BiLSTM was used to train the model to enhance the correlation between the data. Then, the settlement value of a concrete dam hydropower station was taken as example 1 for dam deformation prediction based on the BES-BiLSTM model. Another concrete dam horizontal displacement value was taken as example 2 to verify the model performance. Finally, the prediction results of the BES-BiLSTM model were studied in comparison with those of the traditional long and short term memory neural network (LSTM) model and the BiLSTM model. The results show that the BES-BiLSTM model has stronger fitting and prediction capabilities than the single traditional LSTM and BiLSTM models, which can be used for deformation prediction of concrete dams and slopes.

In order to study the viscoelastic properties of hydraulic asphalt concrete, bending creep tests under different temperatures and stress conditions were carried out. The Burgers model was used as a constitution model for the viscoelastic mechanical behavior of hydraulic asphalt concrete, and a nonlinear fitting of the test data was carried out by the most rapid descent iteration method to obtain the fitting curves and Burgers model parameters under different test conditions. By analyzing the variation law of the parameters, the function equation of the parameters with temperature and stress was established by using Origin polynomial fitting function. The creep behavior of hydraulic asphalt concrete was predicted. The test results show that the Burgers model optimized by the most rapid descent method can better fit the test curve, and the fitted correlation coefficients are all greater than 0.996, especially in the isokinetic creep stage, the fitted curve is closest to the test curve; Under the condition of constant stress, the parameters of the Burgers model decrease with the increase of temperature; Under the condition of constant temperature, the parameters E₁ and E₂ increase with increasing stress, and the parameters η₁ and η₂ decrease with increasing stress.

To solve the problem of low recognition accuracy caused by insufficient power data feature mining, this paper proposed a novel power data identification method based on multi-domain feature analysis and feature selection. Firstly, aiming at the shortcomings of existing power data feature extraction methods, a feature extraction method based on empirical mode decomposition (EMD) and Hilbert transform (EMD-Hilbert) was proposed, and the power features and V-I trajectory features of power data were quantified. Secondly, based on random forest and generalized sequence backward selection search strategy, the optimal feature subset was obtained. The random forest was employed to build a recognition model for the power data. Finally, the experimental results verified the effectiveness and identification accuracy of the proposed method. The results show that the proposed method can utilize the complementarity of different features to overcome the problem of low accuracy by single feature, and further improve the model recognition performance through feature selection.

In order to shorten the start-up time of the hydroelectric generating set and improve the stability of the generating set 's start-up process and non-loading, a start-up optimization strategy of hydropower unit based on improved grey wolf search coupling cuckoo algorithm was proposed. This fitness function weighs the two index values of the unit ' s start-up frequency ITAE index and the unit 's start-up time and standardizes them. Two penalty functions of unit frequency overshoot and unit frequency steady-state error are introduced to effectively improve the start-up performance evaluation index of the hydroelectric generating set. An improved grey wolf search coupled cuckoo algorithm (IGWSCSA) based on good point set theory to improve the initial population is proposed to optimize the start-up parameters of the generating set. Based on the simulation experiment of the refined model of the speed control system, the optimal parameters are obtained to shorten the start-up adjustment time of the generating set, and the overshoot is reduced from 0.235 to 0.004, which greatly optimizes the start-up speed and frequency fluctuation of the hydroelectric generating set.

Climate change and urbanization development have brought great challenges to reservoir flood control and disaster mitigation, and reservoir regulation is one of the important non-structural means for controlling floods. Therefore, this study applies the bibliometrics method and visualization analysis tools (CiteSpace and VOSviewer) to conduct a systematic quantitative analysis of the Chinese literature regarding the research topic of reservoir flood control regulation. The results indicate that the number of Chinese literature on reservoir flood control regulation can be divided into three periods in terms of the publication time, and the number of publications in different periods witnesses the development history of reservoir flood control regulation technology in China; The co-occurrence analysis of keywords provided the top 10 keywords in terms of frequency and centrality. The emergence analysis provided the development history of high popularity keywords since 2000. Cluster analysis classified keywords with significant correlation and displayed the relationship between different clusters; The analysis of authors, institutions, and literature sources can provide guidance for relevant researchers in the Chinese journal selection during the manuscript submission and the collaborator choices in Academia.

The movable guide vane of domestic large hydropower units in early stage was mostly made by sand casting, which had the characteristics of large abnormal shape parts and they were located in the water wheel room of the units with narrow space. At present, the nondestructive testing of the area where the movable guide vane is hided in the shaft sleeve of large hydropower unit in service is generally carried out after the movable guide vane is lifted out during the unit overhaul period. This paper attempts to test it though phased array testing technology, modeling simulation and simulated test block test. This method is successfully applied in actual detection. Finally, the problem that coarse crystal, long sound path and abnormal shape of casting movable guide vane have serious attenuation, loss of sound energy, and difficulty in receiving defect echo is solved. The feasibility of nondestructive detection on the hided area of casting movable guide vane in completely assembling state of large hydropower units in service is verified.

The water flow disorder, shock, spray splashing out of the side wall and incomplete water jump are often caused by insufficient discharge energy dissipation in the pool. In order to solve this problem, the influence law of the layout of T-shaped pier and its parameter variation on the hydraulic characteristics in the ballast tank was studied by using the model test method and numerical simulation. The results show that the energy dissipation rate increases with the increase of the length of T-shaped pier legs; The water depth increases with the installation of the impingement baffle, and the efficiency increases, and the energy dissipation rate decreases with the increase of the impingement baffle; The flow state of the water in the stilling pool is stable after the double-row T-shaped piers are arranged, and the energy dissipation increases first and then decreases with the increase of the distance between the front and back. According to the simulation results, a reasonable scheme is recommended and verified by model test. The results show that the energy dissipation rate of the recommended scheme reaches 76.06%, which increases by 12.51%. The flow state is stable and meets the engineering requirements.

Under the situation of "abundant and dry electricity supply" in Sichuan Province, affected by complex market environment factors and intensified power supply competition, accurate prediction of power generation plan is the key to optimizing the power generation mode of hydropower in dry periods in the basin. This paper analyzed the power supply capacity of the main grid, new energy power, power regulation capacity of the national power grid, outsourcing power transmission capacity and power generation capacity of the provincial hydropower and thermal power, respectively, and established a forecasting method for the generation plan of the cascade hydropower stations in the Dadu River basin. The results show that the prediction accuracy of power supply in main grid is 91.8%, and the prediction accuracy of wind and solar power generation is 87.4%. The prediction accuracy of the medium and long-term overall power generation plan of the hydropower station belonging to Guoneng Dadu River Basin Hydropower Development Co., Ltd. is 90.5%. The model can effectively predict the electricity quantity of each power source and calculate the medium and long-term power generation plan of the cascade hydropower stations in the Dadu River basin, and intelligently generate the fluctuation process under different working conditions based on the prediction results, which provides technical support for the scientific dispatching and operation of the cascade hydropower stations.