Optimal operation of cascaded hydroelectric power plants in the power market

An improved network flow algorithm, which includes the minimum cost network flow and the same period network flow, is proposed to solve the optimization of cascaded hydroelectric power plants in a competitive electricity market. The typical network flow is used to find the feasible flow and add the discharge water to different cascaded hydroelectric power plants at the same step. The same period network flow is used to find the optimal flow and add the power output at a different step. This new algorithm retains the advantages of the typical network flow, such as simplicity and ease of realization. The result of the case analysis indicates that the new algorithm can achieve high calculation precision and can be used to calculate the optimal operation of cascaded hydroelectric power plants.

Effect of Modeling Range on Structural Analysis for Powerhouse of Hydroelectric Power Plant by FEM

In this paper,three different modeling ranges were selected in the structural analysis for a hydropower house.The analysis was carried out using ABAQUS 6.6.The modeling range has a remarkable effect on finite element method(FEM) calculation result at the middle position of typical cross-sections where the concrete is relatively thin,and at the region close to turbine floor.If the ventilation barrel,floor slabs and columns above turbine floor are excluded from FEM model,the maximum rise difference of pedestal structure increases by about 24% compared with that of the whole model.It is indicated that different modeling ranges indeed affect FEM calculation result,and the structure above turbine floor in the FEM model should be included.

Current State of High 120 m Concrete Dam Bratsk Hydroelectric Power Plant

The research object was high 120 m concrete gravity dam of the Angara Bratsk hydroelectric power plant. The state of the concrete dam is estimated based on the results of continuous supervision performed by site personnel as well as periodic monitoring. According to the classification of the interrelations in the system ＂concrete-environment＂, there were selected some important parts of dams and a comprehensive analysis of concrete was executed on these parts. Concerning the complex research of concrete, a combination of full-scale tests with core-sampling has been proposed. Core samples tests had an object to study the deep concrete layers and to determine the specific indicators such as strength, density, porosity, comparative diameter of capillary pores, CaO content in cement stone and others. Obtained findings and recommended criteria can be applied when selecting technologies for constructing dams that guarantee their durability in the north.

3-D Fracture Network Modelling in Hydropower Engineering Based on Optimal Monte Carlo Simulation

Effectively and accurately modelling the spatial relation of fracture surfaces is crucial in the design and construction of large hydropower dams having a complex underlying geology. However, fracture surfaces are randomly formed and vary greatly with respect to their spatial distribution, which makes the construction of accurate 3-D models challenging. In this study, we use an optimal Monte Carlo simulation and dynamic conditioning to construct a fracture network model. We found the optimal Monte Carlo simulation to effectively reduce the error associated with the Monte Carlo method and use dynamic conditioning to ensure the consistency of the model with the actual distribution of fractures on the excavation faces and outcrops. We applied this novel approach to a hydropower station on the Jinshajiang River, China. The simulation results matched the real sampled values well, confirming that the model is capable of effectively and accurately simulating the spatial relations in a fracture network. © 2017, Tianjin University and Springer-Verlag Berlin Heidelberg.

Risk Modelling of Organic Pollution in Lake Sediments

A risk situation of organic pollutants accumulation in the sediments of the dams from Cascade “Middle Iskar” (NW Bulgaria) is simulated in the present study. The aim is risk modelling of organic pollution in lake sediments and on base of the investigated key chemical and enzymological parameters to risk assessment. A model process in lab scale with addition of whey as a source of organic pollutants was simulated. Two situations near to real conditions were studied: 1) at a decreased concentration of organic pollutants (chemical oxygen demand was 0.265 gO2.kg-1) in the case of discharge of sediments downstream of the river (control situation);2) at an accumulation of organic pollutants (chemical oxygen demand was 1.463 gO2.kg-1) in the sediments (risk event). The dynamics of chemical oxygen demand (COD), concentration of proteins and lactose as well as of the key enzymological indicators (phosphatase activity index—PAI, anaerobic dehydrogenase activity, protease and ?-galactosidase activities) were investigated. The data from Risk Assessment showed that there is a hazard from higher protein concentration at the end of the process in comparison with the control situation. The risk about COD and lactose concentration during the risk modelling was acceptable. The obtained results showed that the PAI can be used as an indicator for early warning of the organic pollution with protein nature.

Performance analysis of a floating photovoltaic covering system in an Indian reservoir

Floating photovoltaic(FPV)systems are one of the globally emerging technologies of renewable energy production that tend to balance the water-energy demand by effectively saving the evaporated water from reservoirs while generating electrical power.This study presents the performance analysis of a model FPV plant in an Indian reservoir.The Mettur dam reservoir located in Tamil Nadu,India with a hydroelectric power plant of 150-MW capacity is considered as a test case.The preliminary design of the FPV plant is proposed based on a detailed study of the key design elements and their suitability for Indian reservoirs.The proposed plant is numerically analysed for various tilt angles,mounting systems and tracking mechanisms in order to assess its potential power generation.A flat-mount system in landscape orientation was found to exhibit a high performance ratio.Further,a fixed-tilt FPV system with a panel slope of 10°and an FPV system with single-axis tracking were found to be suitable for the Mettur reservoir.Further,cost analysis of the FPV system is also presented along with the carbon-footprint estimation to establish the economic and environmental benefits of the system.The results show that the total potential CO_(2) saving by a FPV system with tracking is 135918.87 t CO_(2) and it is 12.5%higher than that of a fixed-mount FPV system.