1. DEMAND-BASED FREQUENCY CONTROL (DBFC) Jason W Black, Marija Ilic MIT March 15, 2002

2. Intro to DBFC Loads Respond to Frequency deviations Decentralized control – similar to AGC Utilizes energy based (e.g. Water Heaters, AC) rather than power based (e.g. lights, Televisions) loads

3. Motivation Islanding/Mini-Grids –Growth in DG –Replacement of T&D investments by DG Issues with Renewable DG –Uncontrollable and uncertain Power Production Necessitates additional AGC and Reserves

4. Appliance/UsePercent of Consumption Hot Water25 Heat23 Refrigeration10 Freezer4 Demand Side Potential Energy dependent Loads (Residential): * From ELCAP Study in Pacific Northwest

5. Control Scheme Control Needed: Where: And Sampling Time:

6. Single Control Characteristic f act PP AGC ff -f act

7. Aggregate Control Characteristic TSTS  P L t PP Slope =

8. Simulations Islanded SystemMini-Grid

9. Simulation Assumptions Asynchronous Wind Generator with random deviations Sequence of Equilibria - No Transient stability Issues 20% of Load Participation 5 minute activation time of controls

10. Simulation Results 01002003004005006007008009001000 -0.15 -0.1 -0.05 0 0.05 0.1 0.15 0.2 0.25 Uncontrolled Controlled Frequency Deviation (Hz) Time (s) Frequency Deviation (Hz) 01002003004005006007008009001000 -4 -2 0 2 4 6 8 x 10 -3 Uncontrolled Controlled Time (s) Islanded SystemMini-Grid

11. Conclusions DBFC can alleviate DG issues such as: –Islanding –Reserve Requirements –Lack of Controllability of renewables DBFC can augment AGC Potential for competitive bidding for AGC or reserves

12. Issues Costs of Implementation –Metering accuracy –Native (appliance level) vs Local Response (building level) Droop Characteristics –Unknown for load and generation Willingness to Participate and level of participation needed

13. References 1.Black, Jason W., Ilic, Marija, “Survey Of Technologies And Cost Estimates For Residential Electricity Services”, Proceedings IEEE Power Engineering Society Summer Meeting, Vancouver, Canada, July 2001. 2.Constantopoulos, P., Schweppe, F., and Larson, R., “ESTIA: A Real-Time Consumer Control Scheme for Space Conditioning Usage Under Spot Electricity Pricing”, Computers Operations Research, Vol. 18, No 8, pp 751-765, 1991. 3.Haykin, S., Communication Systems, Wiley and Sons, 1983. 4.Ilic, M., Skantze, P., Yu, C-N., Fink, L.H., Cardell, J., "Power Exchange for Frequency Control (PXFC)", Proceedings of the International Symposium on Bulk Power Systems Dynamics and Control-IV: Restructuring, Santorini, Greece, August 23-28, 1998. 5.Ilic, M.D. and J. Zaborszky, Dynamics and Control of Large Electric Power Systems, Wiley Interscience, May 2000. 6.Pratt, R. G., C. C. Conner, E. E. Richman, K. G. Ritland, W. F. Sandusky, M. E. Taylor. “Description of Electric Energy Use in Single Family Residences in the Pacific Northwest”, DOE/BP-13795-21, Bonneville Power Administration, Portland, Oregon, 1989. 7.Ilic, M. “Model-based Protocols for the Changing Electric Power Industry”, Proceedings of the Power Systems Computing Conference (PSCC), Spain, July 2002. (Under Review). 8.Schweppe, F., et al., “Homeostatic Utility Control”, IEEE Transactions on Power Apparatus and Systems, Vol. PAS-99, No. 3, May/June 1980.