2. Course organizationSteven Low CMS, Caltech Winter 2010

3. cs/ee 146 W F

4. cs/ee 146 Wed Fri

5. Gencos Transcos ISO/RTO LSE (Utilities)

6. Where does electricity come from generator generator transmission Transcos substation Transmission: enerator to distribution Transmission: from generator to substation, long distance, high voltage Distribution:from substation to customer, shorter distance, lower voltage

8. Distribution

9. Generation

10. Transmission

11. Where can we help?

13. US power distribution Source: DoE, 2008 Smart Grid Intro

15. 10% of generation and 25% of distribution facilities are used less than 400 hrs per year, i.e. ~5% of time

16. Existing power plants can provide 73% of light vehicles

17. If they are plug-ins that recharge at night

18. Will reduce oil consumption by 6.2M barrels a daySource: DoE, Smart Grid Intro, 2008

20. China: 326 GW / 248 Wpc(2006);

21. EU: 322 GW / 700 Wpc(2004)Source: DoE, Smart Grid Intro, 2008

23. Future trend Source: DoE, Smart Grid Intro, 2008

24. Generate more than power... US CO2 emission Elect generation: 40% Transportation: 20% Source: DoE, Smart Grid Intro, 2008

25. US Energy Flow -1999Net Primary Resource Consumption 102 Exajoules

26. US Energy Flow -1999Net Primary Resource Consumption 102 Exajoules

28. Distribution

29. Generation

30. Transmission

31. Where can we help?

33. How much is reliability worth? Source: DoE, Smart Grid Intro, 2008

34. US power grid Source: Roger Anderson, Columbia University 2004

35. US power transmission Old infrastructure Average generating station build in 1960s Average age of substation transformer: 42 yrs (expected life span: 40 yrs) Before PCs and Internet! Since 1982, peak demand outgrows transmission capacity by 25%/yr From 1988-98, electricity demand rose by ~30%, while transmission capacity grew by ~15% Annual investment in transmission capacity has dropped 50% since 1975 [Wu et al, Proc IEEE, 2005] Source: DoE, Smart Grid Intro, 2008

38. Gencos, transcos, utilities

39. Different timescale

40. Transmission projects: 5-10 yrs

41. Generation projects: ~2 yrs

42. Uncertainty in matching supply & demand

43. Renewable sources, demand response

44. Substitution between trans capacity, gen capacity, demand mgt

46. Enabling technologies AMI (Advanced Metering Infrastructure) Enable demand response Promote user participation PMU (Phasor Measurement Unit) Real-time, global, synchronized measurement At ms timescale ICT integration with grid High speed WAN allows real-time and global monitoring at control centers High performance computing allows faster control decisions Integrating renewables & distributed sources

47. Conclusions Grid connects generation to load Gridmust become more efficient Demand and generation will continue to outpace transmission capacity Grid must integrate distributed and renewablesources Sustainability Grid must promote demandresponse Cutting peak demand has a large impact Integrate and exploit EV

49. Distribution

50. Generation

51. Transmission

52. Where can we help?

55. Current grid control Second line of defense Control center EMS Substation RTUs sample power measurements SCADA sends measurements to CC every 2-4s State estimator computes a snapshot of system equilibrium N-1 contingency simulation of dynamic behavior Preventive control: change system operating conditions before a fault to ensure the system can withstand the fault Timescale: 2-4s Based on global info

56. Current grid control: issues Different timescales drive independent actions by relay system and CC This gap has led to missed opportunity in preventing cascading outages E.g., NA blackout & Italian blackout of 2003 No analytical tools for emergency control No dynamic system model for stability analysis after fault Rely on simulation: too slow for real-time control Necessitates conservative open-loop control

57. Solution: grid+ICT Both issues due to ICT limitation Data acquisition system (SCADA) CC computational power ... that can be drastically improved More computational power in CC Faster SCADA communications over WAN GPS-based PMUs provide real-time and synchronized power measurements Future PMUs+ICTcan provide system-wide synchronized data on ms timescale

59. state estimation

60. contingency analysis

61. OPF dispatch

62. simulation

63. human in loop

64. decentralized

65. mechanicalrelay system local slow fast

67. state estimation

68. contingency analysis

69. OPF dispatch

70. simulation

71. human in loop

72. decentralized

73. software controlled

75. Where can we help Distributed sense & respond in SG Integration of solar and wind power Pricing and optimization of demand response Architecture and protocols to implement these algorithms These problems are interconnected Each requires engineering+economics

76. Integration of solar/wind Challenge: solar/wind are unreliable Questions How much renewable power can current grid carry? How can real-time/forecast weather data help predict supply? How (much) can geographical diversity improve reliability? Can EV serve as storage? How? How to do optimal power flow with intermittent sources?

77. Pricing demand response Questions How to compute optimal prices for demand response? How to price interruptible power for demand response?

78. Architecture and protocols Questions What protocols are needed to support above control and optimization mechanisms? What architecture features are essential? Where does current architecture fail? Cyber-physical aspect of control and protocols Protocols that enhance cyber-physical security

80. Distribution

81. Generation

82. Transmission

83. Where can we help?

85. SCE Info (Mani) Peak demand control Peak hour: 10/year Spread 15 min of peak over 45 min = 1 power plant Voltage control Stable & low voltage (e.g. 105V) at end users = great saving (How) Can real-time control over smart grid achieve it? Workforce: 50% of SCE retiring Automation, machine learning can help Market/demand response: Irvine project What data is available? What does it tell us?

86. SCE Info (Mani) Battery + solar/wind How much benefit? SCE has a real system and needs answer Protocols Current SCE system: large number of non-standard/insecure/inefficient protocols In addition to ideal protocols, need migration strategy

89. cs/ee146 Fri class Potential presentations: Solar power: model, literature Simulation: OpenDSS & examples (Julian/Roger) Smart grid protocols, Irvine project (Chris) Electricity market: OPF, transmission rights Net arch/security & smart grid