Voltage Stabilization With Shunt Reactors
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Transcript of Voltage Stabilization With Shunt Reactors
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Voltage stabilization in transmission grids with fixed and variable shunt reactors
ABB Transformers, Tomas Olsson, Syracuse (NY), 6/4/2013
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ABBMonth DD, YYYY | Slide 2
ABB Red Tie event, 6/4/2013.Agenda
Reactive power compensation, Why shunt reactors?
Reliable Design of shunt reactors General design Sound and Vibrations Variable shunt reactor (VSR) Testing
Transmission applications with VSR
References and summary
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Reactive power compensation,Why shunt reactors?
ABB Transformers, Tomas Olsson, Syracuse (NY), 6/4/2013
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ABBMonth DD, YYYY | Slide 4
Apparent power consists of active(true) and reactive power components
P = S*cos Q = S*sin
Reactive power compensationDefinitions
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ABBMonth DD, YYYY | Slide 5
Active (True) power
Voltage and current in phase, cos = 1
Reactive power compensationDefinitions
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ABBMonth DD, YYYY | Slide 6
Reactive power
Voltage and current out of phase 90 deg, cos = 0ind
Inductive circuit, we say that the current lags the voltage.Capacitive circuit, we say that the current leads the voltage.
Reactive power compensationDefinitions
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ABBMonth DD, YYYY | Slide 7
To run a marathon with your hands in your pockets is very tiresome
The swinging movement of your bodyhas to be compensated with your arms.
This arm movement could be called a reactive power needed to help you move forward and also to keep the body balance
Likewise in an electrical power system the reactive power in balance is the carrier of the true power.If the reactive power is consumed the voltage decreases, its ability to transport the true power decreases.
Reactive power compensationDefinitions
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ABBMonth DD, YYYY | Slide 8
Reactive power compensationVoltage control
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ABBMonth DD, YYYY | Slide 9
Reactive power compensationVoltage control
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Transmission planning in North AmericaThe ISO/RTO Council (IRC) is comprised of 10 Independent System Operators (ISOs) and Regional Transmission Organizations (RTOs) in North America. These ISOs and RTOs serve two-thirds of electricity consumers in the United States and more than 50 percent of Canada's population
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ABBMonth DD, YYYY | Slide 11
Reactive power compensationVoltage control
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ABBMonth DD, YYYY | Slide 12
Reactive power compensationVoltage control
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ABBMonth DD, YYYY | Slide 13
1. Stability on long line transmissions2. Voltage control during light load
conditions
Reactor restores voltage to specified value
Voltage increase fromcapacitive generation
X
X
1
U
XQ
Q
Q
Q
X
Application of shunt reactors
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ABBMonth DD, YYYY | Slide 14
AC power cable is never loaded with its natural load (losses, heating and cooling)
Always more reactive power is produced than what is absorbed
Need for shunt reactors.
Reactive Power Generation in cables
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ABBMonth DD, YYYY | Slide 15
Reactive power compensationVoltage control
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ABBMonth DD, YYYY | Slide 16
Reactive power compensationVoltage control
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ABBMonth DD, YYYY | Slide 17
Zc = sqrt( l/c) Surge impedancePSIL = V02 / Zc Natural load at transmission voltage V0At PSILInsulation is uniformly stressed at all points along line
Power factor is unity, cos = 1The natural reactive power is zero
Reactive power compensationVoltage control
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ABBMonth DD, YYYY | Slide 18
Reactive power compensationVoltage control
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ABBMonth DD, YYYY | Slide 19
Reactive power compensationVoltage control
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ABBMonth DD, YYYY | Slide 20
Reactive power compensationVoltage control
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A
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The shunt reactorA voltage
regulating device Electrical power systemTransmission line at no load condition, I2=0
V1 V2
I1 I2
V1 = Vr cosVrAt 200 miles, electrical length at 60 Hz is 23,2 degrees (at 50 Hz is 19,3 degrees)V2 will be 1,088 pu (1,06 pu)
I1 = 0,429 pu !!! Q1 = 0,429 PSILThere is a line charging current in the sending end generators
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ABBMonth DD, YYYY | Slide 22
Reactive power compensationVoltage control
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The shunt reactorA voltage
regulating device Electrical power system
V1 V2
I1 I2
Transmission line at no load condition and X chosen so that V2 = V1
At 60 HzMidpoint voltage = V1/cos (/2)= 1,021 puI1= I2= Q1 = Q2 = 0,2055 PSIL
Required rating of shunt reactorAt 500 kV voltage system, ZSIL = 250 ohm
Q2 =
= 205 Mvar (3 phase)
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ABBMonth DD, YYYY | Slide 24
Reactive power compensationVoltage control
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ABBMonth DD, YYYY | Slide 25
Degree of shunt compensationZc = Zc / sqrt( 1-ksh) ; ksh positive, inductive compensation
Shunt reactors - increase virtual surge impedance Zc- reduce virtual natural load PSIL
100 % inductive shunt compensation, ksh =1- reduces PSILto zero- increases Zcto implies a flat voltage profile at zero load.
Reactive power compensationVoltage control
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P2, Q2
U2U1
(R) + X
Q
At natural loading, SIL; P2 = PSIL ( reactive power balance)
U1 U2
1,0 pu
Application of shunt reactorsVoltage profile
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P2, Q2
U2U1
(R) + X
Q
At no or low load (P2), voltage profile, Ferranti effect
U1 U2
1,0 pu
Application of shunt reactorsVoltage profile
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P2, Q2
U2U1
(R) + X
Q
At no or low load (P2), voltage profile with connected SR
U1 U2
1,0 pu
Application of shunt reactorsVoltage profile
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P2, Q2
U2U1
(R) + X
Q
Increased load (P2), voltage profile with connected SR
U1 U2
1,0 pu
Application of shunt reactorsVoltage profile
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P2, Q2
U2U1
(R) + X
Q
Increased load (P2), voltage profile with connected VSR
U1 U2
1,0 pu
Reactor power less than rated power.
VSR = Variable Shunt Reactor
Application of shunt reactorsFine tuning of the voltage with a variable shunt reactor
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ABB Reactors (oil immersed), Types and usage
Shunt reactorsVoltage control
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Reliable Design of shunt reactorsABB Transformers, Tomas Olsson, Syracuse (NY), 6/4/2013
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Rigid gapped core limb for low sound level1. Non-flexible grain oriented steel core sheet 2. Bounded with well proven stiff steatite spacers3. Spacers are machined to exactly the same heightPrecision crafted process ensures: Small axial movements Low vibrations & sound
DesignLow sound
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Earthed shieldno stress concentrationtowards core or winding
Winding centre entry and ground potential towards yokes reduces overall size and losses
Neutral
HV line terminal
DesignWinding arrangement
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It should withstand the loadof 40 cars, applied 120 times per second for 30 years continuous without rattling and high noise
DesignWhy to be careful when buying a reactor?
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Options for sound reduction Typical sound levels
Internal noise control only:Sound power level 80 95 dB(A)Sound pressure level 65 75
dB(A)
With sound panels:Sound power level 70 85 dB(A)Sound pressure level 55 65
dB(A)
With sound enclosure:Sound power level 65 80 dB(A)Sound pressure level 50 60
dB(A)
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OvervoltageOperating voltagesVoltage
Current
Application of shunt reactorsLinearity
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Variable Shunt Reactor (VSR)ABB Transformers, Tomas Olsson, Syracuse (NY), 6/4/2013
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ABB Group June 10, 2013 | Slide 39
Variable shunt reactor applicationsTo foresee the future?
We cannot today foresee the grid conditions of the future
Generation and load patterns Interconnections Regulations Need for reactive power compensation
Trend towards controllability, flexibility and intelligence of the networks
The expected life time of a reactor is 30-40 years
This talks to the favor of variable shunt reactors
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Neutral
Phase terminal
Neutral
Phase terminal
OLTC An unconventional Reactor built on conventional technology
Design solutions taken from our way of building Shunt Reactors and Power Transformers
VSR winding concept
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Normal shunt reactor Regulated shunt reactor
VSR design concept
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Feasible regulation ratio, R, versus operation voltage
VSR feasible Mvar output ranges
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On-load tap changer ABB
Three-phase neutral point tap changer of the diverter switch type
With conventional or vacuum current interrupters
VSR
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Control of LTC of a VSR
Manual / Remote control
Automatic relay controlControl parameters, voltage and Mvar
ABB Group June 10, 2013 | Slide 44
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TestingABB Transformers, Tomas Olsson, Syracuse (NY), 6/4/2013
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Winding resistance Applied voltage test Inductance and loss measurement Zero-sequence impedance Accessories and small wiring Switching impulse test Lightning impulse test PD-measurement Audible noise test and vibrations Test of temperature rise Measurement of harmonics Inductance curve measurement Insulation resistance measurement Capacitance and power factor in insulation
DesignFull scale test
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GC C
T1 T2
R
DesignFull scale test
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Transmission applications with VSRABB Transformers, Tomas Olsson, Syracuse (NY), 6/4/2013
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Variable Shunt Reactors (VSR) benefits
Statnett Norway
Reduced voltage jump at switching on operation.Coarse tuning of SVC equipment for best dynamical operation.Reduction of number of breakers. No parallell fixed reactors.Adjusting of seasonal related loads.Adjusting of daily dependable loads.Flexible spare unit possibility.Flexibility for new load conditions in the network. At revisions for example.Flexibility to move reactor to other locations.
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Variable Shunt Reactors (VSR)
420 kV120-200 Mvar
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ABB GroupJune 10, 2013 | Slide 51
High voltage level situation in the state, especially in the north.
Surplus of reactive power . Therefore big need for inductive power compensation. VSR solution gives flexible voltage control.
Dominion (VA)Variable shunt reactor applications
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ABB GroupJune 10, 2013 | Slide 52
Dominion (VA)
A, Substation Carson.B, Substation Garrysonville.C, Substation Yadkin.D, Substation Hamilton.E, Substation Jefferson street.F, Substation Idylwood.
Voltage stabilisation, Virginia state.
VSR 50-100 Mvar, 242 kV, 7 units.
Variable shunt reactor applications
B
DF
C
E
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ABB Group June 10, 2013 | Slide 53
Q Q
EHVEHV
X X
Reactor placed on the high-voltage side
Reactor power compensation from generators not longer reliable
Minimize number of breaker operations
Extended use of cables put higher demand on reactive power compensation
Eliminating air core reactors on transformer tertiary
Air core reactors take place and are spreading magnetic field
Tap changer used to keep voltage at constant value
Variable Shunt Reactor to Dominion, Virginia USA.
NEW OLD
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ABB GroupJune 10, 2013 | Slide 54
Variable Shunt Reactor50-100 Mvar, 242 kV
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ABB GroupJune 10, 2013 | Slide 55
Variable Shunt Reactor
Equipped with sound housing for sound level environmental impact.
50-100 Mvar, 242 kV.
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Case, Wind Power generation in Texas
Sharyland Utilities part of CREZ
Wind energy transmission to consumer centres in eastern TX
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ABB Inc. June 10, 2013 | Slide 57
Wind Power Generation in TexasSharyland Utilities part of CREZ
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Wind Power generation in TexasFinal stage
Flexibility use for transmission line expansion and voltage stability
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Variable shunt reactor applicationsSharyland Utilities
ABB in tank tap changer VUCG for variable Mvar output.
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Variable shunt reactor applicationsSharyland Utilities
Reactive power compensation flexibility for better voltage control. More cost effective customer solution to two or more reactors with fixed ratings.Smaller footprint.Less number of breakers and breaker maintenance.Customer chooses ABB VSR for the reliability.
50-100 Mvar/345 kV
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Zero Miss Phenomena (and other VSR application)
Siphon transmissionline, 400 kV
Cable transmissionline from wind mill park, 235 kV
1. Askaer S/S, 50-110 Mvar, 2 units to avoid zero miss phenomena. TC in min Mvar position when cable is energized.
2. Tjele S/S, 70-140 Mvar, to minimise voltage jump min Mvar position when switched in.
3. Revsing S/S,70-140 Mvar, to minimise voltage jump min Mvar position when switched in.
4. Grenaa S/S, 120 Mvar, compensation of sea cable from wind mill park.
5. Trige S/S, 60 -120 Mvar, 2 units to compensate for variable wind power generation and loss optimisation.
1
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3
45
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ABB VSR World wide referencesCustomer Nominalvoltage
(kV)Ratingrange,3phase(Mvar)
Type Yearofdelivery
Ghana,Africa 161 918 OLTC 4units19891unit2001
GEWCologne,Germany
110 1030 DETC 1unit1996
ChannelIslands,UK 132 716 OLTC 2unit1999
Sonabel,BurkinaFaso,Africa
225 1330 OLTC 1unit2004
Statnett,Norway 420 120200 OLTC 1unit2008Statnett,Norway 420 120200 OLTC 2units2010Statnett,Norway 300 80150 OLTC 2units2010ECoVannkraft,Norway
420 120200 OLTC 1unit2010
DominionVirginia,USA
242 50100 OLTC 3units20094units20101unit 2014
SvenskaKraftnt,Sweden
400 110180 OLTC 1unit2010
Energinet dk,Denmark
235 60120 OLTC 2units2011
Statnett,Norway 420 90200 OLTC 8units 2012/20131unit 2014
Sharyland Utilities TX,USA
345 50100 OLTC 1unit 2013
Energinet dk,Denmark
400 5011070140
OLTC 3units 2013/20142units 2013/2014
CenterPointEnergyTX,USA
143 2550 OLTC 1unit 2014
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ReferencesABB Transformers, Tomas Olsson, Syracuse (NY), 6/4/2013
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ABB Shunt reactorsReferences
170 Mvar, 525 kVto APS, Arizona
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150 Mvar, 345 kVto New York Power AuthorityEquipped with a sound enclosure for very low sound emission ~ 55 dB
ABB Shunt reactorsReferences
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ABB Shunt reactorsReferences
80 Mvar, 230 kVto PEPCOequipped with sound panels
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Summary
AC apparent power (MVA) has two components, Active power (MW) and
Reactive power (Mvar).
Voltage is influenced by the level of Reactive power (AC system).
The Shunt Reactor is a regulating device to limit the voltage.
High manufacturing accuracy is requested to make reliable shunt reactors.
The Variable Shunt Reactor (VSR) principle is to regulate number of
electrical turns by a tap changer.
VSR is used by customers to satisfy the demand for improved flexibility
(economy driven) in the grid.