The Duncan-Zhang model is not able to reflect the influence of the mid-major stress on the strength and deformation of the rockfill body in the finite element calculations of the panel rockfill dam. The Duncan-Zhang E-B model and its optimization model for the panel rockfill dam has been developed by the secondary development of ANSYS based APDL language. The Duncan-Zhang E-B model and its optimization model were used to calculate the three-dimensional finite element static force of a panel rockfill dam in Yunnan Province. The results show that the settlement of the dam body was reduced, the horizontal displacement was reduced, and the stress change was small. The strain results obtained from the optimization model are closer to the actual data. The optimizaion Duncan-Zhang E-B model considering the medium principal stress can better reflect the stress-deformation characteristics of the panel rockfill dam.

The reservoir flood control operation problem has the characteristics of multi-stage, nonlinear and multiple complex constraints. The research of solution method will help to improve the effect of flood control optimal operation. Differential evolution algorithm (DE) has a good effect in the application of reservoir optimal operation, but it is prone to premature convergence and fall into local optimum due to the random search strategy. In order to balance the global and local search ability of DE, this paper proposed an improved differential evolution algorithm SDE, which is used to improve the search ability by considering the differential mutation strategy of fitness ranking and to improve the development ability by random selection mechanism. The related numerical experiments verified that the SDE convergence is significantly better than that of the DE, GA, PSO, and ACOR. The results of case study show that the SDE is better than POA and DE in terms of the feasible solution, calculation time, accuracy, convergence stability and speed. The average flood-peak rate of the SDE is 0.17%-4.26% higher than the POA, and is 0.13%-1.26% higher than the DE.

In order to improve the control performance of hydro-turbine speed control system containing surge tanks, this paper proposes a control parameter optimization method based on the improved whale optimization algorithm (IWOA). Firstly, the mathematical model of the turbine speed control system with surge tanks was established. The turbine inlet head-flow transfer function containing the dynamics of surge tanks was established by using the continuity equation and pipe transfer function. And then the turbine speed control system model with surge tanks was formed together with the turbine speed control model. The time integral value of the speed deviation of the turbine in this system was used as the fitness value in the optimization process, and IWOA was used to perform optimization of the PID controller parameters of the study object with the objective of minimizing this fitness. The results show that the IWOA algorithm has the advantages of fast convergence speed and high accuracy, and the optimized PID controller provides better regulation and robustness to various types of disturbances.

The shaft system of hydropower unit has a significant impact on the stability of the unit. The degradation assessment of the shaft system can visually reflect the operating condition of the unit. This paper presents a method for assessing the degradation of the unit’s shaft system using instantaneous orbit feature image and conditional adversarial generative network (CGAN). Firstly, the vertical signals of each bearing were constructed as a complex signal, and the multivariate complex variational mode decomposition (MCVMD) method was used to process the signal and extract the instantaneous orbit features to construct the instantaneous orbit feature images. CGAN was used to construct the health model. The health model can fit the distribution of feature images in different operating conditions in healthy state and thus output health feature images. The healthy indicator was constructed using the differences between real and healthy images. The genetic algorithm was used to optimize the weights of multiple bearings in order to reduce the volatility of the comprehensive degradation curve in the healthy zone. The proposed method was tested on the unit's shaft system data and its validity has been proved.

The escape of oil mist from bearing oil groove of power station will not only pollute the environment of power station, but also bring safety hazard to electrical equipment. Combined with the actual situation of hydropower station, the installation of oil mist absorption device can help to discharge excess oil mist from oil tank and effectively avoid the pollution problem of oil mist in power station. In order to investigate the variation of oil mist distribution, velocity, pressure at measuring points and discharge amount of oil mist in the oil tank, numerical simulation calculation of thrust bearing oil tank with negative pressure oil mist pipe was carried out. It is found that after complete oil mist discharged, most of the oil mist can be effectively discharged; The overall change of the amount of oil mist at the outlet follows the law of rising first and then falling. Under the suction pressure of -500 Pa, the maximum discharge amount of oil mist could reach 0.008 23 kg/s. After the oil mist is discharged, the pressure drop at the oil tank upper region reaches 96.07%, and the reduction of the pressure difference can effectively prevent the oil mist from escaping to the cover plate, the wind tunnel, the rotor and so on. The research can provide some theoretical help for the oil mist discharge process of oil tank so as to better formulate the oil mist control strategy.

Aiming at the shortcomings that traditional water weirs cannot measure the sand content of runoff and the traditional measurement methods are not accurate, it is difficult to realize online measurement in the field of dam water weirs. By analyzing the negative correlation between the sand content of the water flow of the water weir and the gray value of the image, sand volume measurement technology was proposed to automatically measure the sand content of the water flow of the weir. The test results show that the deviation between the detection result of sand content and the actual value is low, and it is a convenient, efficient and real-time determination method. The research results have certain reference value for dam seepage monitoring.

Aiming at the problem that the convective heat transfer coefficient depends on experience in the calculation process of arrester temperature rise, a method of determining convective heat transfer coefficient was proposed. The temperature field distribution inside the arrester was studied. The influences of pollution, wind speed and sunshine on the temperature rise of the arrester at different damp degree and different damp positions were analyzed. The results show that under different influencing factors, the convective heat transfer coefficient of the arrester ranges from 5 to 31, 27 to 35 and 19 to 34 W/(m²·℃), respectively. The pollution location will affect the temperature rise distribution of MOA surface, and the greater the degree of moisture, the more significant the impact on temperature rise. With the increase of wind speed, the temperature on the valve plate decreases slightly. However, the surface temperature decreases greatly. The influence of sunshine on the temperature rise of lightning arrester is obviously increased, but it is smaller than that of pollution and wind speed.

It was planned to carry out excavation and treatment of the deep trough in Maozhou Estuary for the construction of the new town, which occupied the -3 m deep trough. The Pearl River estuary physical model was used to carry out tide hydrodynamics modeling test and suspended load model test to simulate the siltation distribution of the deep trough after one year of implementation. The test results show that the hydrodynamic characteristics and flow pattern of the study area have changed and the average siltation near the Maozhou Estuary reaching 0.75 m is more serious than that in downstream with 0.53 m, the -3 m deep trough remains connected with the whole widening rate is 1.57% and the thalweg is distributed along the Shenzhen shoreline with the minimum elevation is -3.40 m. The section morphology shows that the siltation on the right side is more serious than the left side and the upstream is more serious than the downstream. The treatment scheme changed the riverbed, the river regime will be significantly adjusted in the short term, but the -3 m deep trough can be maintained. The scheme is generally feasible.

Considering the importance of reasonably setting water prices for water transfer projects in promoting the healthy operation and sustainable development of the projects, taking water resources allocation project around Beibu Gulf as an example, this paper put forward a new idea to calculate the water price. Firstly, the influencing factors of the project water price were identified through sensitivity analysis. And then through in-depth consideration of the value of each factor and its time change process, the calculated water price is low before and high after, which is realistic and easy to bear as well as conducive to the connection between the water transfer price and the current water price in the receiving area. The results show that the design parameters of water price scheme are reasonable and the calculation results are feasible. This study can provide a certain reference for the water receiving area government in the cost accounting and water price formulation of this project.

In the high proportion hydropower market, it is of great practical significance to establish a reasonable day-ahead quotation strategy for hydropower plants to ensure the effective participation of hydropower in the market. Firstly, the uncertainty of the clearing price of the system on the operation day was considering. Based on the identification of historical similar days, Gaussian process regression was used to establish the probability prediction method of the day-ahead clearing price. Furthermore, considering the revenue preference and risk aversion psychology of decision makers, and taking the maximum expectation of the hydropower plant's own power sales revenue as the goal, the day-ahead piecewise capacity optimization bidding method for cascade hydropower stations was constructed. Finally, the feasibility and effectiveness of the proposed method were verified by the simulation analysis of the day-ahead piewise capacity declaration of the actual cascade hydropower stations.