نشریه سد و نیروگاه برق آبی ایران
پیاپی 14 (پاییز 1396)

Increasing water elevation in dam reservoirs increases power plant working time and hydroelectric energy. If gated spillway is implemented, water elevation of reservoir can be increased without changing the dam height. Application of gate for spillways however increases discharge per unit width and the potential of cavitation attack. In the present work, using Flow3D software first the accuracy of the model was verified with experimental data of a stepped spillway. In the next step the spillway was gated keeping the flow discharge constant. To do this, the elevation of the ogee was increased and the chute width was narrowed. The main purpose of this study was to evaluate the pressure and cavitation potential in the gated step spillway. Studying flow condition in various gate opening showed that lower gate openings cause high negative pressures at the first step downstream of the gate. In the lowest opening of 10% -9.2 m pressure was observed at the first step tip. In addition, according to the results, tail of the gate pier caused flow separation and negative pressure was observed at the step at its downstream. The present work showed that numerical models are powerful instruments for optimization and design of hydraulic structures

Project cost management and control is a major problem in some large projects cost hundreds of millions and sometimes billions of dollars from the budget exceeded the forecast is something very disturbing. A crucial factor in the successful completion of each project is to predict the correct fee (P. Smith, 2014). In this study, the methods used to estimate the cost of large hydroelectric dams were studied and then with the help of estimation method (Gordon, 1983) parameter estimates in construction and Msthdat, Accord, machinery and equipment, land, project staff remuneration, other assets not producing and the overall cost of the dam to dam Seimareh, Scroll, Karun 3 and Karun 4 with growth rates of 8%, 10%, 13%, 15%, 17% and 20% in the cost of approved and fees were assessed and finally to estimate appropriate and predictable cost projects, hydropower in two approved and paid the coefficient k (a factor which is based on engineering judgment for each project) in three parts, maximum, minimum and average is calculated

In the past, dams were for drinking water supply and agricultural purposes, but today due to hydroelectric power and other purposes has been further developed. Forecast seepage from the earth fill dam embankment is a complex and dynamic issue. In this study, an artificial neural network (ANN) used to estimate the seepage of the dam embankment, "Bukan Shahid Kazemi" paid. To achieve this goal, the piezometric data set includes 864 data were used. The results that the proposed model showed that the model quite successful in finding purpose and high- speed operation. Using statistical parameters and applications show that the proposed network is well train and has high potential in estimating leakage.

Based on the history of the occurrence of abundant HSE problems in the construction phase of dams and hydropower plants (as a source of renewable energy), identification and assessment of HSE risks in these projects is of high importance. So, the aim of this study is determined to provide a model for the evaluating HSE risks in the construction phase of Bakhtiari dam and hydropower plant. First, risks were identified using the literature of the issue and interviews with experts. Then, the identified risks were analyzed using FMEA method combined with fuzzy logic. Since the severity parameter is more ambiguous for the experts than the two other parameters, it was calculated by considering the following four sub-criteria of cost, time, quality and individual. The weights of these criteria were achieved using fuzzy AHP method. Based on the results, the highest risk priority number of environmental risks is related to aquatic habitat quality loss and the highest risk priority number of safety and health risks is related to decrease in the individual's concentration and performance. Finally, among total risks, aquatic habitat quality loss, soil erosion escalation, and decrease in the individual's concentration and performance were identified as the most important risks respectively.

Dam building projects put serious impacts on the environmental parameters. Therefore, risk assessment of the dam is one of the most important aspects in managing environmental risks of dams. The construction and operation’s activities of Azad Dam on Kumasi River in Kurdistan provinc were investigated to assess the consequent environmental risks from this plan. Firstly, in this paper, environmental risks were identified based on their criteria including importance, severity, and probable occurrence by Delphi questionnaire method. Then the aforementioned risks criteria were weighted by using Entropy method. In the next stage, Hierarchical Additive Weighting (HAW), Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) and Elimination et Choice Translating Reality (ELECTRE) methods, three techniques of Multiple Attribute Decision Making (MADM) methods were used to rank the probable risks. Results showed that the most important risks of the Azad Dam plan are Soil contamination and flora destruction, reduction in water quality in Kumasi River, intense reduction of organic matter and nutrients in Kumasi River flow at down side

Micro-hydro power plants are now considered as a major source of of renewable energies. They are reliable and are highly efficient in the producing small quantities of energy. These plants often produce electricity in rural areas; However, micro-hydropower generating units generally isolated from the power grid and require to the efficient systems of control in order to keep of parameters such as power and frequency in any work setting. Two machines has been used in the structure of micro-hydro power plant, namely a doubly feed induction generator (DFIG) and a permanent magnet synchronous machine (PMSM). DFIG placed in the variable speed generators category and they are very used due to the higher efficiency and the less mechanical stress. The active and reactive power control is one of the important advantages of these generators. In this paper, novel design of a controller based on predictive control strategy has been shown which that duty is the control of active and reactive power of DFIG based on micro-hydro power plant energy conversion system. The simulation results with Matlab / Simulink and experimental results with the micro-controller based on STM32F407 platform show effectiveness, robustness and accuracy of the controller.