Bindner, Henrik W.

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Downloaded from orbit.dtu.dk on: Dec 20, 2017Control Schemes for Small Distributed Energy ResourcesBindner, Henrik W.Publication date:2009Document VersionPublisher's PDF, also known as Version of recordLink back to DTU OrbitCitation (APA):Bindner, H. W. (2009). Control Schemes for Small Distributed Energy Resources [Sound/Visual production(digital)]. 2nd Wind Energy Systems Workshop: Wind Power and Flexible Load Control in Systems with LargeScale Wind Power, Risø, Denmark, 28/10/2009Control Schemes for Small Distributed Energy ResourcesHenrik BindnerSenior ScientistWind Energy Division, Risø DTUWES Workshop 28.10.09P t ti  O tliresen a on u ne• Background/Introduction• Functions to be provided by small DER• Issues/Requirements• Examples• Summary and conclusion29/10/20092 Risø DTU, Technical University of DenmarkB k dac groun• Increased amounts of WE• Increased need for regulating capacity and reserves on different time scales• Desire to decrease dependence on large central power plants for system services• Consumption side has a potential for participation since part of the load can be deferred• More sources of ancillary services– Many TSO’s are including consumption side– Requirements for large contributions• (substitute fossile fuels in heating and transport thus linking other energy subsystems)29/10/20093 Risø DTU, Technical University of DenmarkWh t i  it  ta s we wan• We want to utilize the potential resources already present in the tsys em• We want a cheap system since the individual contributions are small• Flexible: – Ability to fine tune function– Change behaviour depending on contextImplement several functions–• Scalable• AutomaticLittle or no user intervention required during setup and –operation• User and system interests/needs/requirements• Deterministic behaviour/predictable29/10/20094 Risø DTU, Technical University of DenmarkCl  f f tiasses o unc ons• System supporting functions – ancillary services• System operation optimisation– Peak shaving– Economic optimisation/trading• Shifting loads to low load situations– Wind power coordination29/10/20095 Risø DTU, Technical University of DenmarkA ill  S i  D i tinc ary erv ce escr p on• Continuous Regulation– Provided by online resources with automatic controls that respond rapidly to operator f d d d k drequests or up an  own movements. Use  to trac  an  correct minute-to-minute fluctuations in system load and generator output.• Energy Imbalance Management– Serves as a bridge between the regulation service and the hourly or halfhourly bid-in energy schedules; similar to but slower than Continuous Regulation. Also serves a financial (settlement) function in clearing spot markets.• Instantaneous Contingency Reserves– Provided by online resources equipped with frequency or other controls that can rapidly increase output or decrease consumption in response to a major disturbance or other contingency event.• Replacement Reserves– Provided by resources with a slower response time that can be called upon to replace or supplement the Instantaneous Contingency Reserve in restoring system stability.• Voltage Control– The injection or absorption of reactive power to maintain transmissionsystemvoltages within required ranges• Black Start– Generation able to start itself without support from the grid and with sufficient real and reactive capability and control to be useful in system restoration.From: G. Heffner et al: Loads Providing Ancillary Services: Review of International Experience, LBNL-6270129/10/20096 Risø DTU, Technical University of DenmarkWh t  th  ia are e ssues• How can millions of units be handled in a coordinated way• How is flexibility obtained• How can it be cheap– Communication– Computing requirements• Reliability• Topology/grid limitations/control areas– Local vs. Global issues29/10/20097 Risø DTU, Technical University of DenmarkT iff  fi d  d i  h d lar s – xe or ynam c sc e u e• Very simple to implement • Aggregation• User can be in control, and is often in the loop• It can be automated– Not needed• Control signal– Price schedule/time• Current situation of grid is not taken into account (only predicted situation when • Communication– Needed, oneway• Flexibilityprices were settled)• If prices are updated often, behaviour will approach real – Limited, often User dependent• Scalabilitytime price systems – Good• Cost– Low29/10/20098 Risø DTU, Technical University of DenmarkF  b d l d h ddirequency ase oa s e ng• Disconnection of load in t  it ti• Aggregationex reme s ua ons– Frequency based– Both under- and over-frequency– Not needed• Control signal– frequencyC i ti• Implementation is simple• Only active in contingency situations• ommun ca on– Not needed• FlexibilityPre programmed• Reconnection and synchronisation of state can be an issue– -• Scalability– good• Cost• Amount that is being disconnected cannot be directly controlled• Very short response time– low29/10/20099 Risø DTU, Technical University of DenmarkF  t lrequency con ro• Normal operation mode i.e. load has to be served  but can be• Aggregation– Needed if flexible,deferred• System frequency is availableand easy to measure• Can be implemented without• Control signal– frequency• CommunicationNot needed  but then inflexiblecommunication, but is theninflexible• Local bottlenecks cannot behandled without communication– ,• Flexibility– Limited• ScalabilityImplementation dependent• Fast response time–• Cost– Implementation dependentSystemControllablel dDisturbanceFrequencyR fSystemFrequencyError29/10/200910 Risø DTU, Technical University of Denmarkoa se erence FrequencyR l Ti  P i  Si lea me r ce gna s• Needs transparent mechanism for price generation• Aggregation– Not needed (at loads)• Requires broadcast of price signal• Bottlenecks implies different pricesfor different areas• How real time is real time• Control signal– price• CommunicationNeeded  price broadcast• Will the system be stable/what otherfunctions are required• Will all loads participateTh  i b li– ,• Flexibility– User determines cost function• Scalabilityd• e pr ce curve can e non- near• The TSO will not know the behaviourdue to price changes• The user determines the pricef ti– goo• Cost– lowDi t bunc onSystemControllableloadss ur anceSystem ReferencestateSystemStateSystemImbalance PriceSignalG ti29/10/200911 Risø DTU, Technical University of Denmarkenera onVi t l A lir ua pp ances• Aggregation of similar entitiesA t  t l  it hi  • AggregationN d d• ggrega or con ro s sw c ngdirectly• Using bidirectional communication load shapes can be constructed– ee e• Control signal– Switching commands/time to switch• Communication• Can pre-charge unit for improved/increased behaviour at later time• For scalability only few hundred – Needed, uni/bidirectional• Flexibility– Various load shapes can be implementedare grouped• More aggregation layers are requiredM  d d  h   • Scalability– Good?• CostL ?• ore a vance curve s apes canbe implemented• Short response time– ow29/10/200912 Risø DTU, Technical University of DenmarkSummaryTariffs Load-sheddingFrequencycontrolReal time price signalsVirtual AppliancesAggregation Not needed Not needed Not needed Not needed NeededControl signal Schedule Frequency Frequency Price SwitchingcommandsCommunicatio Unidirectional Not needed Not needed Needed  price Needed  n,broadcast,uni/bidirectionalFlexibility Limited, oftenuserPre-programmedLimited UserdeterminesVarious load shapes can bedependent cost function implementedScalability Good Good Implementation dependentGood Good?C t L L L L L ?os ow ow ow ow ow29/10/200913 Risø DTU, Technical University of DenmarkC l ionc us on• TSO’s are willing to include consumption side as a source of ill  ianc ary serv ces• Challenge is to include small resources connected at the low voltage network in the control of the system• Most schemes are only implementing one function and are therefore not fully exploiting the potential• Relies on communication is available or is pre-programmed and inflexible• There is room for implementation of more complex and flexible behaviour -> Policy-based control29/10/200914 Risø DTU, Technical University of DenmarkTh k an you29/10/200915 Risø DTU, Technical University of Denmark

Control Schemes for Small Distributed Energy Resources

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Control Schemes for Small Distributed Energy Resources

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