Ernest Camm_S&C_Dynamic reactive power control for wind power plants [Modo de compatibilidad]Dynamic Reactive Power Control Dynamic Reactive Power Control for Wind Power Plantsfor Wind Power Plants
©2009 www.sandc.com©2009 www.sandc.com
for Wind Power Plantsfor Wind Power Plants Techwindgrid ’09 Grid Integration SeminarTechwindgrid ’09 Grid Integration Seminar
Madrid 20/21 April 2009Madrid 20/21 April 2009
Ernst Camm Charles EdwardsErnst Camm Charles Edwards Ken Mattern Stephen WilliamsKen Mattern Stephen Williams
Presentation OutlinePresentation Outline
•• Introduction to S&C Electric CompanyIntroduction to S&C Electric Company
•• Introduction to Dynamic Reactive Power Control for Introduction to Dynamic Reactive Power Control for
Wind Power PlantsWind Power Plants
•• InverterInverter--based Dynamic Compensatorsbased Dynamic Compensators•• InverterInverter--based Dynamic Compensatorsbased Dynamic Compensators
•• Hybrid Reactive Power CompensatorsHybrid Reactive Power Compensators
•• Power Factor Control Using Hybrid Reactive Power Power Factor Control Using Hybrid Reactive Power
CompensatorsCompensators
by WTGsby WTGs
•• SummarySummary
Introduction to S&C Electric CompanyIntroduction to S&C Electric Company
•• Established in 1911Established in 1911
•• EmployeeEmployee--owned companyowned company
USAUSA
•• Leading provider of products Leading provider of products
and services for electric and services for electric
power switching, protection, power switching, protection,
automation, power quality automation, power quality
solutions, and engineering solutions, and engineering
servicesservices
Introduction to S&C Electric CompanyIntroduction to S&C Electric Company
•• Manufacturing & engineering Manufacturing & engineering
–– Franklin, WIFranklin, WI
–– Alameda, CAAlameda, CA
•• S&C subsidiariesS&C subsidiaries –– S&C Electric Canada LtdS&C Electric Canada Ltd
–– S&C Mexicana, S. de R.L. de C.V.S&C Mexicana, S. de R.L. de C.V.
–– S&C Electric do Brasil LtdaS&C Electric do Brasil Ltda
–– S&C Electric (Suzhou) Co., LtdS&C Electric (Suzhou) Co., Ltd
–– S&C Electric Europe LtdS&C Electric Europe Ltd
Introduction to Dynamic Reactive Power Introduction to Dynamic Reactive Power Control for Wind Power PlantsControl for Wind Power Plants
•• Grid code reactive power Grid code reactive power
requirements for wind power requirements for wind power
plantsplants
–– Vary power factor to meet Vary power factor to meet
system operating system operating
conditionsconditions
production/consumptionproduction/consumption
periodsperiods
Inducti
ve
Capacit
ive
InverterInverter--based Dynamic Compensatorsbased Dynamic Compensators
•• Voltage source inverter using PWM Voltage source inverter using PWM techniques to synthesize a voltage techniques to synthesize a voltage either greater than or less than the either greater than or less than the bus where the inverters are bus where the inverters are connected connected
•• Commercial inverterCommercial inverter--based dynamic based dynamic •• Commercial inverterCommercial inverter--based dynamic based dynamic compensators are available in compensators are available in modules of modules of ±±1.25 MVAR1.25 MVAR at 480 Vat 480 V
•• ShortShort--term capabilities of term capabilities of 3.3 MVAR3.3 MVAR per module (i.e. per module (i.e. 264%264% of the of the continuous rating) for up to continuous rating) for up to 3 3 secondsseconds
•• Capability to swing from full inductive Capability to swing from full inductive to full capacitive output, or vice to full capacitive output, or vice versa, in about versa, in about 2 milliseconds2 milliseconds
InverterInverter--based Dynamic Compensatorsbased Dynamic Compensators
•• Two modules can be connected to Two modules can be connected to
a single 2.5 MVA, 0.48/33 kV stepa single 2.5 MVA, 0.48/33 kV step--
up transformer for connection to a up transformer for connection to a
33 kV (or other medium voltage) 33 kV (or other medium voltage)
collector substationcollector substation
•• Larger dynamic compensators are Larger dynamic compensators are •• Larger dynamic compensators are Larger dynamic compensators are
comprised of multiple comprised of multiple ±±2.5 MVAR 2.5 MVAR
units with stepunits with step--up transformersup transformers
•• A single A single ±±1.25 MVAR module can 1.25 MVAR module can
be connected via its own stepbe connected via its own step--up up
transformer if the total MVAR rating transformer if the total MVAR rating
requires an odd number of invertersrequires an odd number of inverters
Hybrid Reactive Power CompensatorsHybrid Reactive Power Compensators
•• Consist of an inverterConsist of an inverter--based based dynamic compensator and one or dynamic compensator and one or more mediummore medium--voltage mechanicallyvoltage mechanically-- switched shunt capacitor banks and switched shunt capacitor banks and reactorsreactors
•• Dynamic compensator can control Dynamic compensator can control •• Dynamic compensator can control Dynamic compensator can control up to six switched shunt devices up to six switched shunt devices (SSDs)(SSDs) –– Can be configured to control Can be configured to control
either voltage, reactive power, or either voltage, reactive power, or power factorpower factor
•• Dynamic compensator is typically Dynamic compensator is typically sized such that the largest capacitor sized such that the largest capacitor or reactor bank does not exceed or reactor bank does not exceed about 70 to 75% of the rated total about 70 to 75% of the rated total dynamic rangedynamic range
Hybrid Reactive Power CompensatorsHybrid Reactive Power Compensators
•• Installation for 48 MW wind Installation for 48 MW wind
power plantpower plant
compensatorcompensator
–– two 8 MVAR, 33 kV shunt two 8 MVAR, 33 kV shunt –– two 8 MVAR, 33 kV shunt two 8 MVAR, 33 kV shunt
capacitor bankscapacitor banks
•• Provides reactive power in the Provides reactive power in the
range of 0.95 leading range of 0.95 leading
(inductive) to 0.95 lagging (inductive) to 0.95 lagging
(capacitive) power factor at (capacitive) power factor at
the 33 kV POCthe 33 kV POC
Power Factor Control Using Hybrid Power Factor Control Using Hybrid Reactive Power CompensatorsReactive Power Compensators
•• Hybrid reactive power Hybrid reactive power compensators can be used to compensators can be used to dynamically control the power dynamically control the power factor at the POC with response factor at the POC with response times dictated by intentional delays times dictated by intentional delays associated with the switching of associated with the switching of
80
100
80
100
80
100
associated with the switching of associated with the switching of SSDsSSDs
•• Local collector bus voltage and Local collector bus voltage and current sensing and “slow” current sensing and “slow” feedback of voltage and current at feedback of voltage and current at the POC through SCADA allows the POC through SCADA allows compensator to dynamically control compensator to dynamically control the power factor at a remote POC the power factor at a remote POC using a line drop compensation using a line drop compensation algorithmalgorithm
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Hours
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•• Application review must include review of potential Application review must include review of potential
harmonic resonance conditionsharmonic resonance conditions
–– Harmonic resonance analysisHarmonic resonance analysis
–– Harmonic distortion analysis based on representative Harmonic distortion analysis based on representative –– Harmonic distortion analysis based on representative Harmonic distortion analysis based on representative
“ambient” harmonic levels“ambient” harmonic levels
•• In cases where WTGs with power factor correction In cases where WTGs with power factor correction
capacitors are involved, careful attention must also be capacitors are involved, careful attention must also be
paid to any potential resonance conditions caused by paid to any potential resonance conditions caused by
the WTG capacitorsthe WTG capacitors
Harmonic Resonance And Harmonic Harmonic Resonance And Harmonic Current Injection by WTGsCurrent Injection by WTGs
•• If resonance conditions with high If resonance conditions with high local impedances at characteristic local impedances at characteristic harmonic frequencies (i.e. 5th, 7th, harmonic frequencies (i.e. 5th, 7th, 11th, 13th, etc. harmonics) are 11th, 13th, etc. harmonics) are identifiedidentified –– Capacitor banks in the hybrid Capacitor banks in the hybrid
reactive compensation system reactive compensation system reactive compensation system reactive compensation system can be converted to harmonic can be converted to harmonic filter banksfilter banks
•• If resonance conditions due to If resonance conditions due to WTGs with power factor correction WTGs with power factor correction capacitorscapacitors –– Damped CDamped C--type filter commonly type filter commonly
used to lower local impedance used to lower local impedance of the wind power plant over a of the wind power plant over a wide range of frequencieswide range of frequencies
0.01
0.1
1
10
100
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
Harmonic number (n)
Harmonic Resonance And Harmonic Harmonic Resonance And Harmonic Current Injection by WTGsCurrent Injection by WTGs
•• If utilizing WTGs with DFIG or fullIf utilizing WTGs with DFIG or full--
converter WTGs with appreciable converter WTGs with appreciable
levels of harmonic current injectionlevels of harmonic current injection
–– Sometimes necessary to apply Sometimes necessary to apply
a higha high--pass filter to prevent pass filter to prevent
some of the harmonic currents some of the harmonic currents
Reactor
L
Resistor
Rsome of the harmonic currents some of the harmonic currents
from flowing into the system from flowing into the system
causing high levels of harmonic causing high levels of harmonic
voltage and current distortionvoltage and current distortion
–– If hybrid compensator is If hybrid compensator is
applied, one or more of the applied, one or more of the
capacitor banks can be capacitor banks can be
converted to highconverted to high--pass filterspass filters
Capacitor
C
R
SummarySummary
•• Hybrid reactive power compensation systems provide an Hybrid reactive power compensation systems provide an economical means of meeting typical grid code economical means of meeting typical grid code requirements for power factor and voltage controlrequirements for power factor and voltage control
•• The application and associated wind power plant and The application and associated wind power plant and power system parameters must be carefully reviewed topower system parameters must be carefully reviewed topower system parameters must be carefully reviewed topower system parameters must be carefully reviewed to –– Optimize the design of the hybrid reactive power Optimize the design of the hybrid reactive power compensatorcompensator