XX - 1 Control of the SuperGrid Crowne Plaza Cabana Palo Alto Hotel Palo Alto, California, November 6-8, 2002 Bob Lasseter University of Wisconsin-Madison

XX - 2 Long range assumptions Looking years ahead Environmental issues will increase Pressures to reduce carbon fuels Address both transportation and stationary energy needs

XX - 3 Continental SuperGrid DC Grid ac/dc dc/ac Load dc/ac Load dc/ac Load dc/ac Load Nuclear generation (other none carbon sources of energy) Hydrogen cooled superconducting grid DC network (power electronics & losses)

XX - 4 DC Superconducting Network System: Low voltage high current superconducting network (unit connected generation>DC>distribution) Issues Complexity of System control (100s of sources and 100,000s loads) Current control References: Johnson,B.K., R.H. Lasseter, F.L. Alvarado, D.M. Divan, H. Singh, M.C. Chandorkar, and R. Adapa, "High-Temperature Superconducting dc Networks", IEEE Transactions On Applied Superconductivity, Vol. 4, No.3, pp , September Tang, W and R.H.Lasseter, "An LVDC Industrial Power Distribution System without Central Control Unit," PECS, Ireland, June 2000.

XX - 5 How to handle load power needs AC systems; frequency droop Complexity of power flow control Need distributed control 100s of rectifiers 100,000s inverters

XX - 6 Distributed Control Issues Rectifiers (generation or storage) Change power output depending on load. Share load Independent of number Inverters Provides stable ac voltage to the load Provide required power for loads Automatic load shedding Coordination is achieved through dc voltage

XX - 7 Control of injected current Thyristor Controlled Rectifier Assume no resistance in line (some ac losses due to harmonics)

XX - 8 Power Dispatch on dc voltage

XX - 9 Power Dispatch on dc voltage Load shedding area

XX - 10 Single system voltage used for load tracking control All inverters 2 inverters Rectifier

XX - 11 Superconducting Network System: Low voltage high current superconducting network (generation>DC>distribution) Issues System control Current control References: Johnson,B.K., R.H. Lasseter, F.L. Alvarado, D.M. Divan, H. Singh, M.C. Chandorkar, and R. Adapa, "High-Temperature Superconducting dc Networks", IEEE Transactions On Applied Superconductivity, Vol. 4, No.3, pp , September Tang, W and R.H.Lasseter, "An LVDC Industrial Power Distribution System without Central Control Unit," PECS, Ireland, June 2000.

XX - 12 Current levels in superconductors Current flow is a function of over time and the line inductance. In steady state there is a single dc voltage across the system(some ac losses due to harmonics)

XX - 13 Issues:Control of grid currents DC grid Load Need current control devices for each segment Currents in segments are defined by past transients (no unique steady state) Issues of over-currents in segments and faults Adding a de-energized segment

XX - 14 Superconducting Network Power flow control is distributed Network current control requires new devices * (superconducting current transfer device) Point-to-point only transmission Storage needed near loads Ideal transport of H 2 *Johnson,B.K., R.H. Lasseter, F.L. Alvarado, and R.Adapa, "Superconducting Current Transfer Devices for Use with a Superconducting LVdc Mesh", IEEE Transactions on Applied Superconductivity, Vol. 4, No. 4, pp , December 1994.

XX - 15 Ratio of H 2 to electricity? For superconductor cooling only? Include transportation and stationary energy needs? Generate some H 2 at source and some at load? Two pipelines?

XX - 16 Hydrogen only grid? Clusters of microgrids with H 2 generators Small generation placed near the heat and electrical loads allows for reduncey The combined heat and power efficiencies can approach 95% Transportation is integral to system. Technology issues for H 2 grid & storage.

XX - 17 Hydrogen MicroGrid with CHP Campus Owned Distribution (13.2 kV) Heat Distribution Academic Building A Dormitory B Administrative Building Dormitory A Student Union Academic Building B To Other Campus Loads 500 kVA 300 kVA 75 kVA 800 kVA 300 kVA Generator Step Up Transforme r Generator Protection and Control Paralleling Bus (4.8 kV) Voltage Regulator Heat Distribution 1.75 MVA Heat Recovered from ICE Units Load control Communication & Control Signal Path HG Hydrogen

XX - 18 MicroGrids in each building H 2 electric generators are placed at the point of use to provide both electricity and heat storage Hydrogen Reference (http/certs.lbl.gov/) “Integration of Distributed Energy Resources: The CERTS MicroGrid Concept,” R. Lasseter, A. Akhil, C. Marnay, J. Stephens, A.S. Meliopoulous, R. Yinger, and J. Eto April 2002

XX - 19 Issues How to distribute H 2 ? Superconducting current control? Grid vs. point-to-point? H 2 line independent from superconducting line. H 2 microgrids

XX - 20 Possibilities Today Natural gas microgrids > H 2 base Point-to-point dc superconductor