CERTS Microgrids Tom Jahns Professor, University of Wisconsin-Madison LPPC Rates Roundtable May 21, 2013 Wisconsin Energy Institute WEI WEI provides linkage among all organizations associated with energy science, technology and policy work at UW-Madison DER Technologies Dispatchable Sources •! Small internal combustion-engine generator •! Small gas turbines generators •! Microturbines •! Fuel cells Intermittent Sources •! Wind turbines •! Photovoltaic Storage •! Batteries, Ultra-capacitors •! Flywheels How do we deal with 100,000+ DER units? Cluster Loads & DER (interfaced to the grid using a fast switch) •! Microgrids provide the most promising means of integrating large amounts of distributed sources into the power grid •! Microgrids open the door to significant system efficiency reliability improvements :.65% 4;"51<% !"#$% &'()"#*% +,% -((./% 0"1(2% &'()"#*% 3*#4*56% B2.$6% 7.8*(/%452(.9*% :'*=%>*==6% +='9?@#%A/)("$% :=/;<**=% !" Microgrid Drivers Provides system approach to high penetration issues Reduce load outages by ~ 98% (UPS like system) Fast islanding (~1 cycle) Provides for a stiff voltage during events (SVC) Reduced emissions and improve energy efficiencies Effective use of Combined Heat & Power (CHP) No transmission and distribution losses Facilitates demand side management Support renewable sources Provides higher reliability & modularity Autonomous local control (independent of loss of central controller) Graceful degradation Minimize engineering errors/cost/and maximizes flexibility Plug-and-play & peer-to-peer models Microgrids with Fast Controls and Communications Isolating Device (opens during island mode) Utility System Primary Connection (13.2 kV) 1.2 MVA Utility System Interface Control (Synchronization, fault protection, islanding detection, etc.) Generator Protection and Control Load control Heat Recovered from ICE Units Paralleling Bus (4.8 kV) 1.75 MVA Gen 1.75 MVA 1.75 MVA Gen Gen Issues: 0.8 MVA •! Loss of control & communication! •! Extensive site engineering •! Costly heat Heat Distribution distribution system. Communication & Control Signal Path •! Difficult to scale 1.4 MVA EPRI: Campus Microgrid System 6 CERTS Microgrid: Autonomous Components Microgrid with local Combined Heat & Power! Microgrid + CHP! 120 kV 13.2 kV PCC •! Autonomous DER model (independent of central controller) •! Plug & Play Model (avoids extensive site engineering, design errors & allows placement near heat/cooling loads) •! Units control power, frequency & voltage using local information Microgrid + CHP! ! Controller PV CH P CH P P V Other loads L c L L cL L c Storage 7 CERTS Microgrid Frequency Voltage 1.005 pu Vmax 1 pu Vref 0.995 pu Vmin Qlimit Inductive Reactive Power Qlimit Capacitive Reactive power-terminal voltage droop 0.5 pu 1.0 pu Real Power Real power-frequency droop •! Control of individual DGs is achieved using local information only •! Power is balanced using power frequency droop curves •! Voltage is controlled using reactive power droop curves CERTS Microgrid Concept Each DER unit is a grid-forming component (controls ac voltage and frequency). •! Autonomous load following •! Insures multi-unit stability (local voltage control) •! Autonomous load transfer from overloaded source to other sources •! Intelligent load and source shedding The interface switch provides for autonomous islanding and re-synchronizing to the network (opens on IEEE1547 & power quality events) UW Microgrid Testbed Utility System Static Switch 480 V 208 V 20 yd 4 wire Cable Diesel Genset 75 yd 4 wire Cable DG 3 480 V 25 yd 4 wire Cable Static Switch" 9.0 kW Y Loads DG 1 480 V 4.5 kW Y Load Inverter-Based Microsources 9.0 kW Y Loads DG 2 480 V Testbed has been used to develop robust plug-and-play control algorithms defining CERTS Microgrid Demonstrated at Site (inverter-based, no communications & no storage) !!Autonomous load following !!Seamless separation & automatic re-synchronizing with the grid !!Autonomous load transfer from overload source to other sources !!UPS-level power quality !!Stable operation for multi-sourced systems AEP/CERTS Microgrid Test Bed 3-60 kW Sources Loads Static Switch •! #$#"%&$'" """"""())*+())," •! -.$"'-/&" """"""()),+())0" •! -.$"/1234"536789:" """""""())0+;3<=<>4" •! First CERTS Compliant CHP Systems First product to commercially offer CERTs controls algorithms for microgrid operation •! Features: –! Low emission NG engine –! Operated over wide speed range to optimize fuel efficiency –! 700,000 BTUh recoverable heat –! 82.4% (LHV) overall efficiency TecoGen CERTS Microgrid Demonstration "! Alameda County, Santa Rita Jail Objective •! Demonstrate the commercial implementation of the CERTS concept •! Reduce peak electricity demand & demonstrate demand response •! Improve the security and reliability of the power supply •! Improve the fuel cell s performance Equipment •! •! •! •! •! •! 4 MW-hr Lithium Ion battery Two 1 MW diesel generators Smart switch 1 MW fuel cell with CHP 1.2 MW solar on rooftops 12 kV feeder DOE &CEC funded project Military Microgrids ! ! Fort Sill Energy Efficient! Microgrid! •! •! •! •! •! Advanced Distribution and! Control for Hybrid Intelligent! Power Systems:! •! Meshed microgrid with a reliable wireless communication system •! Intelligent distributed controls to promote graceful degradation MAXWELL Air Force Base! •! Interconnecting two buildings •! Demonstrate CERTS advanced controls •! 2- existing MW gen-sets Hybrid CERTS Microgrid 500 kW hr battery 2-200 kW NG gen-sets 30 kW PV 2.5 kW wind Wisconsin Energy Institute Building •!>2CD=*5*$%"#% E*1*C)*(%FGHF% •!@#1='$*6%#*;%<"9<% )./%C"1(29("$%=.)% New UW-Madison WEI Microgrid !I@%7'"=$"#9% •! !"#$%&'()#*%"+,%-'",%% $"&%)".+/%'0%123%45% •! 6'7*)%&(88-9*&%"+,% ,:+'&%#'+;)'--*,%;'% *<(-";*%=!%&'()#*&%% *," What's next? Coupled Microgrids Smart Switch: Two coupled microgrids: •!Seamless separation •!Automatic re-synchronizing •!Distribution level •!Customer level with high Local Reliability & CHP Standard building block for Smart Distribution 17 What is Next? Microgrid as a Grid Resource Controller PV PV Lc L L CHP CHP Lc Lc Storage •! Provides a standard building block for Smart Distribution . •! Dispatchable bi-directional real & reactive power. •! Demand side management. •! Multiple points of electrical coupling. •! Islands & re-synchronizes autonomously.! •! Controller interfaces with system controllers. and locally optimizes the microgrid operation. •! Can have custom features 18 For Discussion •! Can utilities and microgrids be friends? •! Is it possible to imagine creating a “win-win” environment in which utilities embrace DER and microgrids? •! Are the barriers inherent in the basic regulated utility structure? •! Can ratemaking improve the relationship between utilities and microgrids? For More Discussion…. Please contact: Prof. T.M. Jahns [email protected]
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