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Conventional and Renewable Energy Issues
Conventional and Renewable Energy Issues
The structure of the electric utility system is changing due to the deployment of renewable energy sources such as solar and wind power plants in the MW range, and distributed plants (e.g., on roof tops) in the kW ranges. The effects of these changes within the power system call for a study of the present-day load/frequency and voltage control approaches. Islanding operations will result in an enhancement of reliability and local availability of electric power, mitigating the occurrence of large-scale power outages. The reliance on intermittent power generation complicates short-term load forecasting.
Power system analysis tools which are available, such as special transformer configurations, symmetrical components, short-circuit calculations, and Newton-Raphson load flow within a distribution feeder, will be reviewed and applied to voltage control. The frequency- and load control for islanding and interconnected power pools plays an important role for power system operation. Improved conventional and emerging renewable energy sources including short- and long-term energy storage facilities will be designed within the framework of homework assignments that is, case studies. Various techniques for the optimal power flow, reactive power compensation, and filtering within a distribution feeder will be reviewed, and reliability indices and on-line measurement techniques will be applied to decrease power outages.
First, we will review existing power system structure, federal and state regulations, the role of public utilities commissions, international and national standards and the state of deregulation. We will then discuss sources of energy suitable for electric power systems.
After a review of state-of-the-art distribution and transmission systems, the influence of distributed generation on the infrastructure of distribution systems will be discussed. An introduction of symmetrical components and associated short-circuit calculations provide tools for the assessment of systems with distributed generation. The renewable energy sources will be connected to the utility system at low voltage levels, where the system impedance is relatively large. This results in unfavorable transient interaction between the intermittently operating renewable-energy plant with the utility system.
The available renewable sources such as photovoltaic arrays with their required load matching, peak-power tracking, shadowing effects, and wind power generation with constant and variable-speed generators will lead to the combination of solar and wind power plants with short-term storage plants --such as battery and variable-speed hydro plants based on the doubly fed induction generator (DFIG)-- and long-term storage plants such as pump-storage/compressed-air facilities. The fact that wind power plants can change their power output relatively quickly (e.g., 60 MW per minute as reported by a New Mexico wind farm) and compressed-air power plants – which is a long-term storage plant-- have a start-up time of 6 minutes calls for short-term energy storage plants such as either super capacitors, batteries, fly-wheel storage or variable-speed hydro plants which can be deployed within a 60 Hz cycle. These short-term plants are necessary to provide power between the time when the renewable power plant (e.g., photovoltaic, wind) is unable to deliver power and the time the compressed-air power plant can replace the power generated by the renewable power plant. The discussion of cogeneration plants concludes the renewable energy section. The ability to store electric energy will be an important feature of future system with intermittent distributed generation. The merits of batteries, super capacitors, fuel cells, magnetic storage, hydrogen, pump-storage plants, compressed-air plants, and variable-speed hydro plants will be examined.
The management of loads and their control is an important issue of the power system of the future due to the intermittent operation of renewable energy sources. It is proposed to match each intermittently operating renewable source with a short-term storage plant which can complement the insufficient output of the renewable source for about 10 minutes, thereafter, a long-term storage plant will provide power to the system in case the outputs of the renewable sources are still insufficient. Linear and nonlinear loads will be analyzed, strategies for load shedding are devised.
The course concludes with the discussion of on-line measuring methods and components as applied to a utility system. Reliability indices will be used to enhance the overall performance of the electric power system.
- To get informed of existing regulatory procedures, national and international standards, and deregulation procedures.
- To understand the operating principles, design and implementation of improved conventional and renewable energy sources within the electric utility system.
- Application of special transformer configurations, and short-circuit calculations based on symmetrical components to distributed generation networks.
- To design short- and long-term, large-scale storage plants of electric energy.
- To study power plants with optimal performance such as load matching, peak-power tracking, load shedding, and filter applications to improve the quality of power.
- Application of SPICE, MATHEMATICA; and MATLAB software to case studies. Course is geared to utility, industrial process and consulting engineers.
Prerequisites: ECEN 3170 (Energy Conversion I) or equivalent.
Lecture notes available from the Electrical, Computer, and Energy Engineering Department, and a few books are recommended as background material such as :
- J. J. Grainger and W.D. Stevenson, Jr, Power System Analysis, McGraw-Hill, 1994.
- A. J. Wood and B.F. Wollenberg, Power Generation Operation & Control, John Wiley & Sons, Inc., 1984.
- R. Decher, Energy Conversion - Systems, Flow Physics and Engineering, Oxford University Press, 1994.
- R. O’Hayre, S.W. Cha, W. Colella, and F. B. Prinz, Fuel Cell Fundamentals, John Wiley & Sons, Hoboken, NJ, 2005.
- E. F. Fuchs, Electromechanical Systems, Class Notes for ECEN 3170, 2004
- E. F. Fuchs and M. A. S. Masoum, Power Quality in Power Systems and Electrical Machines, Elsevier/Academic Press, February 2008, 638 pages. ISBN: 978-0-12-369536-9.
- E. F. Fuchs and M. A. S. Masoum, Power Conversion of Renewable Energy Systems,Springer, February 2011, 580 pages. ISBN: 978-1-4419-7978-0.
PSPICE, MATHEMATICA and MATLAB.