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PEAC Workshop on DRfor TVA Distributors
September 10, 2002Knoxville, TN
Presented by E.J. HontonResource Dynamics Corporation
DR Interconnection Issues: Standards, Technologies and Impacts on
Facilities use DR to generate power on-site in lieu of gridpurchasesCutting energy costs is a primary motivation, but boostingreliability and quality of power is also a driverCurrently, U.S. manufacturers ship over $3 billion annually inDR worldwide, mostly diesel gensets for backup powerRough market estimates based on emergence of improvedDR units call for $5-10 billion annually in U.S. markets alone(equipment and installation)Service market could be substantial at $1-2 billion annually
The interconnection systemperforms the functions necessary tomaintain the safety, power quality,and reliability of connected EPSsand DRsSystem complexity depends on thelevel of interaction requiredbetween the DR and the EPS
The users wants the ability to use both the DR and grid,sometimes simultaneouslyUtilities may want the ability to remotely dispatch acustomer’s DR unit - the power export optionUser needs grid for backup, standby
Interconnection is Not aSimple Issue: Utility Concerns
Electric power distribution systems designed for one-way operationPersonnel safety and grid stability are dominantconcernsUtilities reluctant to rely on unfamiliar, customer-supplied protective relaying schemesIntegrated interconnection “packages” not generallyaccepted and known
Interconnection is Not aSimple Issue: Customer Concerns
Utility interconnection costs can be a “deal breaker”for smaller-sized projectsSome requirements not understood by customer, andmay appear unreasonableManufacturer, customer and utility DR activities arefrequently not coordinatedInterconnection requirements are far from standard
Understanding the interconnection "black box" marketis important to understanding the future role of andbarriers to DRThe interconnection package is advancing quickly, withfunctional performance available today that was notpossible even 1 year agoThe convergence of software and hardware isproviding protection relaying and coordination functionsat lower cost and at higher reliability
DR Interconnection TechnologyDevelopment at a Crossroads
Digital, multi-function relays emergingRise of inverter technology opened door to inverter-based protective relayingUtility protection and coordination practices have beenbased on “discrete” relays on the utility side of meterUtility protection engineers are now learning andbecoming familiar with digital circuitryTechnology development is now coupled with electronicinformation age
Interconnection “Black Box”The “Black Box” is often more than one boxThe interconnection “black box” provides acombination of functions including power conversion,performance monitoring, protective relaying, andgenerator control and protection“Seamless” power transfer increases complexity withgreater dependence on sub-cycle transfer capability
No Interconnection - Complete Isolated OperationIsolated DR - Automatic Transfer to EPSParallel DR Operation - No Power ExportParallel DR Operation with Power Export
Three organizations are major players in the DR interconnectioncodes and standards arena
– Institute of Electrical and Electronics Engineers (IEEE)– National Fire Protection Association/NEC (NFPA)– Underwriters Laboratories (UL)
Others also issue standards and regulations– International Electrotechnical Commission (IEC)– American National Standards Institute (ANSI)– American Society of Mechanical Engineers (ASME)– American Gas Association (AGA)– Gas Technology Institute (GTI)– National Electrical Manufacturers Association (NEMA)– Electrical Generating Systems Association (EGSA)– Federal, State and Local Governments
Codes and standards set requirements for DRinterconnection equipment manufacture, installation,and operationCodes and standards primarily address reliability,safety and power quality issuesMost standards apply to “components”Limited coverage of interconnection systems
– IEEE P1547– UL 1741
Certification for grid interconnection is a huge gap
BODY OF STANDARDSP1547 Standard for Interconnecting Distributed Resources with Electric Power Systems.
P1589 Standard forConformance TestProcedures forEquipmentInterconnectingDistributed Resourceswith Electric PowerSystem(Lab Certification)
Does the system use an inverter?Does the system have a parallel connection to the EPS?Can the system export power to the EPS?Is the system remotely dispatchable?Application type (and owner/operator), e.g., baseload,cogeneration, emergency/backup, premium, remote?
Microturbine Used for Prime Power, as aPeaking Unit, For Backup or Power Export
DER Prime
Mover
DER Electric
Generator
Interc onnection System
AC
Loads
Area Electric
Powe r Syste m
Powe r
Distribution
Power Flow
Point o f Com mon Coupling
Meter
DC
Loads
Powe r Conversion that Includes: Synchronization for Paralleling Oper ation Local EPS and Area EPS Protective Relaying DER Control and Monitoring Dispatch and Control
Power Conversion that Includes: Undervoltage /Ove rvoltage Under Frequency/O verfrequency Overcurrent Synchronization Ground Fault Overvoltage Active-Anti Island Function
• Exciter control system for generators• Synchronizer to transfer power DR EPS• Automatic transfer switch control• Import/export control• Protective relay functions
− over/under frequency and voltage− directional real and reactive power flow− phase-to-phase current balance
• Metering or net metering• Remote communications capabilities
Categories of InterconnectionEquipment Product Offerings
1. Transfer switches2. Paralleling switchgear3. Dispatch, communication, and control4. DR controls5. Power conversion6. Metering and monitoring7. Relays and protective relaying
Most genset control system components could be andsometimes are built into an interconnection system
• Metering and Monitoring: ABB, Advanced Energy, AlphaPower, Ametek Power Instruments, ASCO, Basler, Beckwith,Capstone, Caterpillar, Cutler-Hammer, Electro Industries,Encorp, Enetics, Generac, GE Zenith, Heliotronics, Hydrogenics,Invensys, L-3 Communications, Liebert, Measurlogic,Omnimetrix, PDI, Power Measurement, Reliable Power Meters,Siemens, Simpson, Square D, Thermo Westronics, Toshiba,Vanner, Woodward, ZTR Control
• Relays and Protective Relaying: ABB, Basler, Beckwith,Capstone, Cutler-Hammer, Encorp, GE Zenith, SchweitzerEngineering Labs, Siemens, Square D, Toshiba, ZTR ControlAll companies are not designing their architecture to the samestandards; not all equipment can work with other components
Siting costs vary greatly by project size, location, complexityand the role of outside parties
“Individual” site specific interconnection packages increasecost of equipment as well
Typical Costs per kWCost Category DR Units <500 kW DR Units >500 kWGenset capital cost $600-1,500 $400-1,200Engineering, permitting, installation $200-700 $150-600Interconnection and testing $75-300 $25-200
Successful integration of all DR technologies into EPSStandards and market requirements must be achievable bythe technologyIncreasingly need seamless transfer of powerMust build in design flexibility - modularity?Increasingly complex control systems, paralleling switchgear, and transfer switches are needed for a smart systemMuch technology exists, and even as incremental technicalimprovements are made, most RD&D efforts are designed toimprove system economics
Defining a single communications protocol (“grid to chip”)Transforming the interconnection system into a set of plug-and-playcomponentsTurning the black box into a distributed metering and monitoringstation of a smart EPSDeveloping more flexible, adaptive, cheaper, and reliable controlsystems using digital processors/telemetry to perform enhancedmetering, logging and dispatchUsing interconnection control and monitoring systems to improveDR environmental performance, as well as unit predictive andscheduled maintenance
Pre-engineered structures thatcontain the functions necessaryfor synchronization and paralleloperation with the grid:− operator interface− controls− protective relays− circuit breakers− synchronization
Generally used for DR units withmore traditional AC output
Designed for use with prime moverswith DC or high frequency AC output(i.e. PV systems, fuel cells, andmicroturbines)In the future, inverter basedinterconnection systems may beapplied to standard reciprocatingengine gensets
10 kW - 1 MW size rangeVariety of “prime movers”Modes of operation
– grid mode and stand-alone mode operation– grid mode and stand-alone mode transition– stand-alone mode to grid mode transition– standby generator start/stop, remote wake-up, standby function– multi-unit capability up to 1 MW for grid and stand-alone operation– reliable synchronization to the grid– remote monitoring/controls/dispatch
T&D upgrade deferralCHP with utility supplying equipment, technical know howPeak shaving by owning or leasing DR at industrial sitePrice incentives to interconnect customer DR (low base rate and high“excessive” use charge) for peak shavingPrice incentives for curtailment programsSmart interconnection system (satellite or internet) that feeds backhealth of the T&D systemInvest limited amounts in multiple DR technologiesCustomer reliability enhancer (no interconnection)Short- and medium-term efficiency and operation gains; long-termtechnology developmentAutomotive tie-ins for hydrogen infrastructure, then fuel cells
Evolving regulations, technologies and market adoption of DRUtilities remain uncertain of impact on their T&D operationsStandardized interconnection may not apply universallyImproved manufacturer interconnection packages - lower costand improved performanceAccelerated activity at state and federal levels regardinginterconnection, with reference to IEEE standard
Both the existing conversion and new technology DR marketsare potentially largeDR interconnection systems exist, but are expensiveInterconnection codes and standards are being developedThe choice of interconnection components and the installationcost depend upon the DR applicationMany manufacturers make products, but not all are modularnor do they all work togetherFurther RD&D is needed to lower costsA modular UIT may be forthcomingDistributors may be able to benefit from DR in several ways
E.J. Honton, Director, Resource Dynamics Corporation,2046 NW Flanders, Suite 24, Portland, OR 97209, 541-462-3118, [email protected]
N. Richard Friedman, CEO, Resource DynamicsCorporation, 8605 Westwood Center Drive, Suite 410,Vienna, VA 22182, 703-356-1300 ext. 203,[email protected]