Considering the wide frequency range, strong nonlinearity, and multimodal characteristics of "double high" power systems, an adaptive identification method for broadband oscillation modes was proposed. Firstly, an adaptive threshold filtering technique was applied to the spectrum of the Blackman-Harris windowed signal to extract the dominant components. Then the three-spectrum line interpolation FFT and the ZoomFFT were used to adaptively analyze the signals after using main-lobe interference criterion of modes with close frequencies. Finally, the proposed method was tested by using 20-mode example signals and a measurement signal of a power system model. The results demonstrate that the method can accurately identify the parameters of complex broadband oscillation modes, adapt to various oscillation scenarios, and meet the signal characteristics of "double high" power systems, thus confirming its applicability and feasibility.

Aiming at the nonlinearity and non-stationary of vibration signals of hydropower units and the timeliness of prediction, this paper proposed a vibration prediction model of hydropower units based on VMD-CIMFs-TCN. Firstly, the VMD algorithm was used to decompose the vibration signal to obtain the IMFs component with the minimum signal distortion, which realizes the accurate decomposition of the vibration signal. Secondly, by calculating the power spectrum entropy and the permutation entropy of each IMF component, the aggregation of the IMF components was realized to reduce the computational load of the prediction model. Finally, the TCN network was used to realize the accurate prediction of CIMFs, and the final vibration signal prediction results were obtained by adding them. The analysis shows that this method shortens the time required for prediction on the premise of ensuring the prediction accuracy, and meets the timeliness of the prediction model.

The multi-energy complementary balance model used in the demonstration of the scale of pumped storage in the new power system only considers the high cost of deep peak shaving brought about by the minimum technical output of thermal power for coal-fired unit peak shaving, ignoring the economic issue of coordinated operation between coal-fired and pumped storage units. This paper proposed to use the economic output coefficient of thermal power and the minimum output coefficient of thermal power as discriminant indicators for coordinated operation of thermal power and pumped storage, and incorporate it into the original multi-energy complementary balance analysis model. From an economic perspective, the scale of pumped storage was predicted with the minimum total annual cost as goal. Taking a certain power grid as an example, the process of demonstrating the scale of pumped storage energy was illustrated, which provides reference for similar power grid development planning and early engineering design work.

In order to solve the problem that the one-dimensional SWMM model is difficult to visually display the submerged depth and range of the study area, taking a residential area in Brighton as an example, the SWMM model coupled with the LISFLOOD-FP two-dimensional hydrodynamic model has a low impact on the residential area. The waterlogging situation before the development and renovation was analyzed and the inundation range and water depth map were made, and three different low-impact development (LID) schemes (single green roof scheme, single permeable pavement scheme, and combination scheme) were designed to transform the residential area. The results show that the inundation range is consistent with the actual waterlogging points, which shows that the two-dimensional coupling model has high reliability, and the three low-impact development schemes can effectively eliminate overflow nodes, reduce runoff peaks, and delay peak occurrence time and water receding time, which is of great significance to improve urban drainage and reconstruction technology.

In order to response the request of hydraulic digital twin, this paper studied how it implement in long linear engine hydraulic project so that the manage system can show any position and any changes of the project. The data linkage inquiry method in both two and three dimension and the shortest distance algorithm innovatively were proposed based on BIM, GIS and geological profile graph. It is implemented through data fusion, data structure design, software design etc., which can make digital scene and geological profile graph's view move and inquire together. The user can immediately acquire mileage, geological conditions, design section, construction and operating state through moving and pre-clicking the cursor. It's proved in a certain water diversion project that the project manager can inquire and acquire real-time project information immediately by using this method without inspect the whole engineering. This method lays the foundation of real-time data inquiry, engineering safety intelligent analysis and production operation management, which implement engineering digital twin to some extent.

The practice of ecological governance and reforestation was carried out by taking Pianyanzi fluctuation zone as the object, proposed the stone cage anti wall technology, stone cage plate slope protection technology, ecological bag slope protection technology, which provides the necessary soil matrix for plant growth and prevents the soil from being soaked by reservoir water and erosion. On this basis, more than a dozen species of water-resistant plants were screened, and different plant species were configured in different elevation areas. After a long period of inundation in one hydrological year, the overall survival rate of trees and shrubs was 54.9% and 35%, respectively. Among them, Taxodium ascendens Brongn, Ascendens mucronatum, Betula nigra, Myricaria laxiflora, and Salix variegata had better submergence tolerance and higher survival rates, which were 84%, 74.2%, 88.3%, 97%, and 95%. They could withstand long-term overtop submergence, and the effect of reforestation in the water-level zone was obvious.

In order to explore the solution to the risk of ponding and waterlogging in the sub-catchment area during sponge city design, SWMM modeling was used to study the peak runoff control characteristics of LID facilities and their combinations under different recurrence interval, as well as the peak runoff control laws of the incremental scale of volumetric LID facilities. The study shows that the peak runoff control effect of volumetric LID facilities is mainly achieved through peak time delay, while the peak runoff control effect of permeable LID facilities is mainly achieved through overall runoff reduction, and the peak runoff control effect of volumetric LID facilities is more significant; Only the combination of permeable LID facilities cannot significantly reduce peak runoff and delay peak time on a rainfall event with a recurrence interval of 5 years or more. When combined with volumetric LID facilities, it can achieve a peak runoff reduction rate of over 20% for rainfall with a recurrence interval of less than 10 years; When the scale of permeable LID facilities increases by 60% or more, the peak runoff reduction effect is more obvious for rainfall with a recurrence interval of 50 years or less; When its scale increases by 80% or more, it can basically ensure that the total runoff volume of post-development does not exceed which of pre-development with a recurrence interval of 50 years or less. The research results are aimed at exploring solutions to the risk of ponding and waterlogging in local areas, which provides theoretical reference for the design of peak runoff control in actual sponge city sub-catchments.

In order to maximize the comprehensive benefits of cascade reservoirs in the lower reaches of the Jinsha River, it is necessary to study the application mode of joint flood control scheduling. Adopting the flood process in different areas with the incoming water from the Jinsha River and the Minjiang River as the mainstay, the flood regulation calculation, flood control analysis, flood control storage capacity utilization, and cascade power generation benefit calculation of the cascade reservoirs in the downstream of the Jinsha River were studied by using relevant mathematical analysis methods. The flood control distribution method of the cascade reservoirs in the lower reaches of the Jinsha River to meet the goal of flood prevention in the Chuanjiang River was studied. The research results show that on the premise of meeting the flood control requirements of the downstream Chuanjiang River, from the perspective of making full use of flood resources and increasing the overall power generation benefits of cascade power stations, in the distribution and dispatching of flood control, it is recommended that the order of flood control storage capacity utilization of cascade reservoirs downstream of the Jinsha River is as follows: Wudongde Reservoir, Xiluodu Reservoir, Baihetan Reservoir. The research results can provide references for rational and scientific flood control operation of cascade reservoirs in the lower reaches of the Jinsha River and similar basins.

Reasonable data mining and accurate prediction and analysis of concrete dam deformation monitoring data are the key means to ensure the safe and long-term operation of the dam. Due to the impact of environmental variables such as temperature and water level, the dam deformation time series has periodic, nonlinear and other change characteristics. Existing intelligent algorithms can not capture the nonlinear relationship of sequences well, A concrete dam deformation prediction model based on EEMD-AEFA-LSTM model was proposed. Ensemble empirical mode decomposition was used to effectively decompose the deformation time series. The long short-term memory network model optimized by the artificial electric field algorithm was used to predict the decomposition components and reconstruct the prediction results. The deformation monitoring data of EX16 and EX24 measuring points of a concrete dam were selected for prediction research. The results show that the prediction accuracy of the EEMD-AEFA-LSTM model is significantly higher than that of the AEFA-LSTM model, PSO-LSTM model, and GA-LSTM model. The average absolute error, mean square error, and root mean square error of the prediction results are the minimum values, providing a new way for accurate prediction of concrete dam deformation.

In order to provide a suitable means for the tidal prediction of the Changjiang Estuary and its adjacent area and for the open boundary conditions of tidal flow numerical model of the Changjiang Estuary, accuracy of NAO.99Jb was evaluated. The feasibility of providing open boundary conditions for tidal flow numerical model of the Changjiang Estuary was studied. The results show that the NAO.99Jb model can accurately simulate the propagation of the tide outside the Changjiang Estuary and its adjacent area; The NAO.99Jb has good accuracy outside the Changjiang Estuary, but has lower accuracy inside the Changjiang Estuary; It is feasible for using the tidal level predicted by NAO.99Jb as the open boundary condition of the tidal flow numerical model of the Changjiang Estuary, and the accuracy is good, which can be further popularized and applied.