2. Outline Introduction to Microgrid. Microgrid Operating Modes. The Need of Microgrid. Interconnected Microgrids – Power Parks. Environmental Aspects. Conventional Grid versus Microgrid. Advantages & Disadvantages of Microgrid. Future Directions on Microgrid Research. References. 8/25/2009 2
3. Introduction To Microgrid What is Microgrid? Itis a small-scale power supply network that is designed to provide power for a small community. It enables local power generation for local loads. It comprises of various small power generating sources that makes it highly flexible and efficient. 8/25/2009 3
4. Introduction To Microgrid What is Microgrid? It is connected to both the local generating units and the utility grid thus preventing power outages. Excess power can be sold to the utility grid. Size of the Microgrid may range from housing estate to municipal regions. 8/25/2009 4
5. Introduction To Microgrid Microgrid Components Distributed Generation Loads Immediate storage Controller Point of Common Coupling 8/25/2009 5
8. Microgrid Operating Modes Grid Connected Mode: Utility grid is active. Static switch is closed All the feeders are being supplied by utility grid. 8/25/2009 8
9. Microgrid Operating Modes Island Mode: Utility grid is not supplying power Static switch is open. Feeder A, B, C are being supplied by Microsources. Feeder D (not sensitive ) is dead. 8/25/2009 9
10. The Need Of Microgrid Microgrid could be the answer to our energy crisis. Transmission losses gets highly reduced. Microgrid results in substantial savings and cuts emissions without major changes to lifestyles. Provide high quality and reliable energy supply to critical loads 8/25/2009 10
11. Interconnected Microgrids Interconnected Microgrids – Power Parks Practical size of Microgrids is limited to a few MVA. For larger loads, it is desirable to interconnect many Microgrids to form a larger Microgrid network called Power Parks. The advantages of this Microgrid structure insures greater stability and controllability for the Power Parks. 8/25/2009 11
12. Environmental Aspects Microgrid encourages the use of the renewable energy sources. Large land use impacts are avoided. CO2 Emissions are reduced. 8/25/2009 12
13. Conventional Grid vs. Microgrid Efficiency of conventional grid is very low as compared to Microgrid. Large amount of energy in the form of heat is wasted in conventional grid. Power sources in case of Microgrid (often referred to as Microsources) are small and are located in close proximity to load. 8/25/2009 13
14. Advantages & Disadvantages Microgrid Advantages A major advantage of a Microgrid, is its ability, during a utility grid disturbance, to separate and isolate itself from the utility seamlessly with little or no disruption to the loads within the Microgrid. In peak load periods it prevents utility grid failure by reducing the load on the grid. Significant environmental benefits made possible by the use of low or zero emission generators. 8/25/2009 14
15. Advantages & Disadvantages Microgrid Advantages The use of both electricity and heat permitted by the close proximity of the generator to the user, thereby increasing the overall energy efficiency. Microgrid can act to mitigate the electricity costs to its users by generating some or all of its electricity needs. 8/25/2009 15
16. Advantages & Disadvantages Microgrid Disadvantages Voltage, frequency and power quality are three main parameters that must be considered and controlled to acceptable standards whilst the power and energy balance is maintained. Electrical energy needs to be stored in battery banks thus requiring more space and maintenance. Resynchronization with the utility grid is difficult. 8/25/2009 16
17. Advantages & Disadvantages Microgrid Disadvantages Microgrid protection is one of the most important challenges facing the implementation of Microgrids. Issues such as standby charges and net metering may pose obstacles for Microgrid. Interconnection standards needs to be developed to ensure consistency. IEEE P1547, a standard proposed by Institute of Electrical and Electronics Engineers may end up filling the void. 8/25/2009 17
18. Future Directions on Microgrid Research To investigate full-scale development, field demonstration, experimental performance evaluation of frequency and voltage control methods under various operation modes. Transition between grid connected and islanded modes on interaction phenomena between distribution generation and high penetration of distributed generation. Transformation of Microgrid system today into the intelligent, robust energy delivery system in the future by providing significant reliability and security benefits. 8/25/2009 18
19. References A. A. Salam, A. Mohamed and M. A. Hannan. "TECHNICAL CHALLENGES ON MICROGRIDS" (DECEMBER 2008) http://www.arpnjournals.com/jeas/research_papers/rp_2008/jeas_1208_146.pdf S. Abu-Sharkha, R.J. Arnolde, J. Kohlerd, R. Lia, T. Markvarta, J.N. Rossb, K. Steemersc, P. Wilsonb, R. Yaoc. "Can microgrids make a major contribution to UK energy supply?" (September 2004) http://eprints.ecs.soton.ac.uk/11276/1/Microgrids.pdf John Stevens. "Characterization of Microgrids in the United States", Sandia National Laboratories (January 2005) http://www.electricdistribution.ctc.com/pdfs/RDC_Microgrid_Whitepaper_1-7-05.pdf Robert H. Lasseter, Paolo Piagi. "Microgrid: A Conceptual Solution", University of Wisconsin-Madison (June 2004) http://www.pserc.wisc.edu/ecow/get/publicatio/2004public/lasseterpesc04us.pdf 8/25/2009 19
20. References "Integration of Distributed Energy Resources - The CERTS MicroGrid Concept", Consultant Report (October 2003) http://www.pserc.org/cgi-pserc/getbig/researchdo/certsdocum0/certspubli/certsmicrogridwhitepaper.pdf "Why the Microgrid Could Be the Answer to Our Energy Crisis" http://www.fastcompany.com/magazine/137/beyond-the-grid.html "How a Microgrid Works" http://science.howstuffworks.com/microgrid.htm “The Rise of MicroGrid Power Networks" http://www.sustainablefacility.com/Articles/Feature_Article/58905d08bd629010VgnVCM100000f932a8c0____ 8/25/2009 20
Each feeder has several circuit breakers and power and voltage flow controllers. The power and voltage controller near each microsource provides the control signals to the source, which regulates feeder power flow and bus voltage at levels prescribed by the Energy Manager.
Interconnectedmicrogrids (power parks) allows us to feed the power