The Experts below are selected from a list of 72 Experts worldwide ranked by ideXlab platform
G. Galasso - One of the best experts on this subject based on the ideXlab platform.
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Adjustable speed operation of pumped hydroPlants
International Conference on AC and DC Power Transmission, 1991Co-Authors: G. GalassoAbstract:With a frequency synchronous converter at the main terminals of a generator or at the collector rings of a three phase rotor it would be no longer necessary to tie the electrical machine synchronously to the grid, so the speed of the hydraulic turbine could be adjusted freely to satisfy the load demand at the maximum possible hydraulic efficiency. In this way the adjustable speed operation of a pumped hydro Plant is an improvement in system performance and is a new flexibility in power Plant site selection and sizing of hydro units. In the case of a HVDC link, where the high voltage AC-DC converter is already required, the possibility of variable speed operation is a further advantage to be added at savings in the transmission line costs. The author describes the improvements in system efficiency and the influence of this way of operation on the design of Panjiakou generators for China.
H. Akagi - One of the best experts on this subject based on the ideXlab platform.
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Large static converters for industry and utility applications
Proceedings of the IEEE, 2001Co-Authors: H. AkagiAbstract:The emergence of high-power semiconductor devices such as insulated-gate bipolar transistors (IGBTs) or injection-enhanced gate transistors (IEGTs) and gate-commutated turn-off (GCT) thyristors or integrated gate-commutated thyristors (IGCTs) enables large static converters to expand into utility and industry applications. For instance, a /spl plusmn/80 kV 50 MW HVDC transmission system based on a string of many IGBTs connected in series was commissioned in 1999. This paper describes the present status of large static converters, with focus on their applications to utility and industry. The applications discussed are: HVDC transmission system, UPFC, flywheel energy storage system, pumped hydro Plant adjustable speed generator, active filters for power conditioning, and steel mill drives. The paper also describes their future prospects and directions in the 21st century, including the personal views and expectations of the author.
M.r. Mohan - One of the best experts on this subject based on the ideXlab platform.
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USE OF Pumped-Hydro AS PEAK-LOAD MANAGEMENT Plant IN OPTIMAL SCHEDULING OF POWER SYSTEMS
Electric Machines & Power Systems, 1997Co-Authors: M.r. Mohan, S. R. Paranjothi, S. Prince IsraelAbstract:ABSTRACT The system demand, during some intervals of a day, may exceed the available system generation (excluding the Pumped-Hydro generation). A Pumped-Hydro Plant may then, be used as a peak-load management unit to safeguard the power system by minimizing the power blackout in order to avoid large deviation in system frequency. In this paper, an algorithm is presented to obtain the optimal schedule for hydro, thermal Plants including the Pumped-Hydro unit by proper selection of initial feasible trajectory for the Pumped-Hydro Plant. An additional constraint is introduced to ensure the power balance in each time interval during the perturbation of water storage trajectory. The proposed method decomposes the problem into hydro and thermal subproblems and solves them alternately. The hydro subproblem is solved using a search procedure namely, the local variation method and the thermal subproblem is solved using a judicious combination of participation factors/linear programming method. Optimal scheduling w...
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Short-term hydrothermal scheduling of power systems with a pumped hydro Plant using the local variation approach
Electric Power Systems Research, 1993Co-Authors: M.r. Mohan, K. Kuppusamy, M. Abdullah KhanAbstract:Abstract In light-load seasons, the operational planning problem of hydrothermal scheduling with a pumped hydro Plant for the next day's demand in a power system is concerned with the determination of generation schedules for the hydro, thermal and pumped hydro Plants to meet the daily system demand so that the total fuel cost of the thermal Plants over the day is minimized subject to the operating constraints associated with the thermal, hydro and pumped hydro Plants as well as the security constraints. The security constraints include network security constraints and the generator outage induced security constraint. This paper presents a new problem formulation by including the generator outage induced security constraint on water storage level to operate the pumped hydro Plant as a spinning reserve unit and a method for the selection of the initial trajectory for the pumped hydro Plant. The effective algorithm used comprises a judicious combination of the participation factor method and the linear programming method. The algorithm is very effective in enforcing security constraints and gives an optimal generation/pumping schedule which can be readily implemented for the next day. A comparison of results obtained with and without the outage induced security constraint is made on a nine-bus system.
S. J. Ghaemsaidi - One of the best experts on this subject based on the ideXlab platform.
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Integrated Pumped Hydro Reverse Osmosis systems
Sustainable Energy Technologies and Assessments, 2016Co-Authors: Alexander H. Slocum, Maha N. Haji, A Zachary Trimble, Ferrara Marco, S. J. GhaemsaidiAbstract:Abstract Ideal head height for pumped hydro energy storage/generation systems and reverse osmosis desalination Plants coincide (500–700 m). Many drought stricken coastal regions have nearby mountains of sufficient elevation to support upper reservoirs at this ideal head height. A good symbiotic match might thus be realized by co-locating a pumped hydro Plant with a reverse osmosis desalination Plant, which we call an Integrated Pumped Hydro Reverse Osmosis (IPHRO) system. Combining systems reduces capital investment, such as pump costs, and solves the desalination brine disposal challenge since 10–20 times more water is required to generate one person’s power needs than to generate their fresh water needs, so brine outflow can be diluted by the turbine output water reducing costs of diffusing outflow pipes. This paper describes an algorithm that weights distance from the ocean and mountain height to explore where around the world such IPHRO systems might be located. Design equations are presented to preliminarily explore the size and cost of an IPHRO system and enable first order site feasibility assessment. An example is given for providing power and water for one million people with an IPRHO system in southern California. Analysis and consideration of other sites is included in a supplementary document.
H. Oman - One of the best experts on this subject based on the ideXlab platform.
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Batteries vs. alternatives for storing energy
IEEE Aerospace and Electronic Systems Magazine, 1996Co-Authors: H. OmanAbstract:Electric utilities need quickly-available sources of power for supplying expected and unexpected peak loads. Among useful sources have been the energy stored in water by pumping it to elevated storage reservoirs, in air compressed into underground chambers, and in batteries. A new power source, tBase-load nuclear and coal-fired steam Plants generate off-peak energy for recharging the depleted storage facility. The aero-derived gas turbine, challenges the economics of these traditional energy-storage means. These turbines have been designed for aircraft where quick startup, rapid change in output power, and high reliability are essential. With a 1426/spl deg/C (2600/spl deg/F) turbine inlet temperature the available efficiencies are 42% in simple-cycle operation and 60% in a combined-cycle power Plant. A recent 84-MW natural-gas-burning peak-power Plant cost $204 per kW. Pacific Gas and Electric's Helmes River Pumped-Hydro Plant had cost $656 per kW. The combined-cycle gas turbine Plants, with their low manpower requirements, are producing power that costs less than power from nuclear power Plants. We examine the performance and economics available from these new power sources.
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Batteries vs. alternatives for storing energy
IECEC 96. Proceedings of the 31st Intersociety Energy Conversion Engineering Conference, 1Co-Authors: H. OmanAbstract:Electric utilities need quickly-available sources of power for supplying expected and unexpected peak loads. Among such useful sources have been the energy stored in water by pumping it to elevated storage reservoirs, in air compressed into underground chambers and in batteries. A new power source, base-load nuclear and coal-fired steam Plants generate off-peak energy for recharging the depleted storage facility. The aero-derived gas turbine challenges the economics of these traditional energy-storage means. These turbines have been designed for aircraft where quick startup, rapid change in output power, and high reliability are essential. With a 1426/spl deg/C (2600/spl deg/F) turbine inlet temperature the available efficiencies are 42 percent in simple-cycle operation and 60 percent in a combined-cycle power Plant. A recent 84-MW natural-gas-burning peak-power Plant cost $204 per kW. Pacific Gas and Electric's Helmes River Pumped-Hydro Plant had cost $656 a kW. These combined-cycle gas turbine Plants, with their low manpower requirements, are producing power that costs less than power from nuclear power Plants. Here, the authors examine the performance and economics available from these new power sources.
