p. ribeiro june, 2002 1 lecture 3 advanced facts devices and applications: performance, power...
TRANSCRIPT
1P. Ribeiro June, 2002
Lecture 3Advanced FACTS Devices and Applications:
Performance, Power Quality and Cost Considerations
Paulo F. Ribeiro, BSEE, MBA, PHD, PE
CALVIN COLLEGEEngineering DepartmentGrand Rapids, MI 49546
http://engr.calvin.edu/PRibeiro_WEBPAGE/[email protected]
10 5 0 5 102
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FACTS
• The Concept• History / Background - Origin of FACTS, Opportunities, Trends• System Architectures and Limitations• Power Flow Control on AC Systems• Application Studies and Implementation• Basic Switching Devices• Conditioners: SVC, STATCOM, TCSC, UPFC, SMES• Specification, Cost Considerations and Technology Trends• Impact of FACTS in interconnected networks• Market Assessment, Deregulation and Predictions
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Ptg
PV
VP
X
XP
The Concept
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A transmission system can carry power up to its thermal loading limits. But in practice the system has the following constraints:
-Transmission stability limits-Voltage limits-Loop flows
Transmission stability limits: limits of transmittable power with which a transmission system can ride through major faults in the system with its power transmission capability intact.
Voltage limits: limits of power transmission where the system voltage can be kept within permitted deviations from nominal.
Loop flows can be a problem as they are governed by the laws of nature which may not be coincident with the contracted path. This means that power which is to be sent from point ”A” to point ”B” in a grid will not necessarily take the shortest, direct route, but will go uncontrolled and fan out to take unwanted paths available in the grid.
The Concept and Challenges
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FACTS devices
FACTS are designed to remove such constraints and to meet planners´, investors´ and operators´ goals without their having to undertake major system additions. This offers ways of attaining an increase of power transmission capacity at optimum conditions, i.e. at maximum availability, minimum transmission losses, and minimum environmental impact. Plus, of course, at minimum investment cost and time expenditure.
The term ”FACTS” covers several power electronics based systems used for AC power transmission. Given the nature of power electronics equipment, FACTS solutions will be particularly justifiable in applications requiring one or more of the following qualities:
-Rapid dynamic response-Ability for frequent variations in output-Smoothly adjustable output.
Important applications in power transmission involving FACTS and Power Quality devices:SVC (Static Var Compensators), Fixed * as well as Thyristor-Controlled Series Capacitors (TCSC) and Statcom. Still others are PST (Phase-shifting Transformers), IPC (Interphase Power Controllers), UPFC (Universal Power Flow Controllers), and DVR (Dynamic Voltage Restorers).
The Concept
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History, Concepts, Background, and Issues
Origin of FACTS-Oil Embargo of 1974 and 1979-Environmental Movement-Magnetic Field Concerns-Permit to build new transmission lines-HVDC and SVCs-EPRI FACTS Initiative (1988)-Increase AC Power Transfer (GE and DOE Papers)-The Need for Power semiconductors
Why we need transmission interconnection-Pool power plants and load centers to minimize generation cost-Important in a deregulated environment
Opportunities for FACTSIncrease power transfer capacitySVC (Nebraska GE 1974, Minnesota Westinghouse 1975, Brazil Siemens 1985)TCSC, UPFC AEP 1999
Trends-Generation is not being built-Power sales/purchases are being
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System ArchitectureRadial, interconnected areas, complex network
Power Flow in an AC SystemPower Flow in Parallel and Meshed Paths
Transmission LimitationsSteady-State (angular stability, thermal limits, voltage limits)Stability Issues (transient, dynamic, voltage and SSR)System Issues (Post contingency conditions, loop flows, short-circuit levels)
Power Flow and Dynamic Stability Considerations
Controllable Parameters
Basic FACTS Devices - Impact of Energy Storage
System Architectures and Limitations
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Power Flow Control on AC Systems
RadialParallel
Meshed
Power Flow in Parallel PathsPower Flow in a Meshed SystemsWhat limits the loading capability?
Power Flow and Dynamic Considerations
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Power Flow Control on AC Systems
Relative Importance of Controllable Parameters
Control of X can provide current controlWhen angle is large X can provide power controlInjecting voltage in series and perpendicular to the current flow, can increase or decrease
50% Series Compensation
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Transmission Transfer Capacity Enhancement
Advanced Solutions
Transmission Link
Enhanced Power Transfer
and Stability
Line Reconfiguration
Fixed Compensation
FACTS
Energy Storage
Better Protection
Increased Inertia
Breaking Resistors Load
Shedding
FACTS
Devices
Traditional Solutions
SVCSTATCOMTCSC, SSSCUPFC
Steady StateIssues
Voltage LimitsThermal Limits
Angular Stability LimitsLoop Flows
DynamicIssues
Transient StabilityDamping Power Swings
Post-Contingency Voltage ControlVoltage Stability
Subsynchronous Res.
FACTS Applications and Implementations
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FACTS Devices
Shunt ConnectedStatic VAR Compensator (SVC)Static Synchronous Compensator (STATCOM)Static Synchronous Generator - SSGBattery Energy Storage System (BESS)Superconducting Magnetic Energy Storage (SMES)
Combined Series and Series-Shunt ConnectedStatic Synchronous Series Controllers (SSSC)Thyristor Controlled Phase-Shifting Transformer orPhase Angle Regulator (PAR)Interline Power Flow Controller (IPFC)Thyristor Controlled Series Capacitor (TCSC)Unified Power Flow Controller (UPFC)
Relative Importance of Different Types of ControllersShunt, Shunt-Series
Energy Storage
Energy Storage
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DevicesDiode (pn Junction)Silicon Controlled Rectifier (SCR)Gate Turn-Off Thyristor (GTO) GEMOS Turn-Off Thyristor (MTO) SPCOEmitter Turn-Off Thyristor (ETO) Virginia TechIntegrated Gate-Commutated Thyristor (IGCT) Mitsubishi, ABBMOS-Controlled Thyristor (MCT) Victor TempleInsulated Gate Bipolar Transistor (IGBT)
Power Electronics - Semiconductor Devices
DiodesTransistors
IGBTThyristors
SCR, GTO, MTO, ETO, GCT, IGCT, MCT
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Power Electronics - Semiconductor DevicesPrincipal Characteristics
Voltage and CurrentLosses and Speed of Switching
Speed of SwitchingSwitching Losses
Gate-driver power and energy requirements
Parameter Trade-offPower requirements for the gatedi/dt and dv/dt capabilityturn-on and turn-off timeUniformityQuality of silicon wafers
IGBT has pushed out the conventional GTO as IGBTs ratings go up.IGBTs - Low-switching losses, fast switching, current-limiting capabilityGTOs - large gate-drive requirements, slow-switching, high-switching lossesIGBTs (higher forward voltage drop)
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VSI CSI
Natural Forced
Synchronous PWM
Hard Soft
Two-Level Multi-Level
SCR GTO IGBT MCT MTO
System
CommutationApproach
SwitchingTechnology
TransitionApproach
CircuitTopology
DeviceType
Power Electronics - Semiconductor DevicesDecision-Making Matrix
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X
E1 / 1 E2 / 2I
P&Q
0 0.5 1 1.5 2 2.5 3 3.50
1
22
0
P1 x delta V1( )
3.140 delta
Real Power Angle Curve
Changes in X will increase or decrease real power flow for a fixed angle or change angle for a fixed power flow. Alternatively, the reactive power flow will change with the change of X. Adjustments on the bus voltage have little impact on the real power flow.
Vx
I
Vxo
Vs
I
Xeff = X - Xc
Vx
Vr
Vc
Vseff = Vs + Vc
VrVc
Vseff
P1 = E1 . E2 . sin () / (X - Xc)
Vs
Phase Angle
Pow
er T
rans
f er
AC Transmission Fundamentals (Series Compensation)
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X
E1 / 1 E2 / 2
IP&Q
P
E1
E2
I
E1 - E2
Injected Voltage
Integrated voltage series injection and bus voltage regulation (unified) will directly increase or decrease real and reactive power flow.
AC Transmission Fundamentals (Voltage-Series and Shunt Comp.)
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1 - prior to fault
2 - fault cleared
3 - equal area
3 >crit - loss of synchronism
Improvement of Transient Stability With FACTS CompensationEqual Area Criteria
1 2 3 crit
A1
A2
Amargin
Max
imum
Po w
e r T
ran s
f er
Phase Angle
no compensation
with VAR compensation (ideal midpoint)
A1 = Acceleration EnergyA2 = Deceleration Energy
Therefore, FACTS compensation can increase
power transfer without reducing the stability margin
Q / V
AC Transmission Fundamentals (Stability Margin)
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Voltage Source Vs. Current Source Converters
CSC AdvDis
VSC
Adv Dis
Device Type
Thyristor Self-Commutation
Thyristor Self-Commutation
Device Characteristic Symmetry
Symmetrical Asymmetrical +
Short-Circuit Current
Lower
+ Higher
Rate of Rise of Fault Current
Limited by DC Reactor + Fast Rise (Due to capacitor discharge)
Losses
Higher - Lower +
AC Capacitors Required Not Required + DC Capacitors
Not Required + Required
Valves dv/dt
Lower (AC Capacitors)
+ Higher
Interface with AC System More Complex Less Complex + Reactive Power Generation
Depends on Current Flowing through Energy Storage
Independent of Energy Storage +
Performance Harmonics -
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System bus
ConverterSwitching
DC-AC
C+
Vdc
s
Shunt Compensation
System busV
Transformer leakageinductance
Transformer
o
X
V
I
Coupling
C+
Vdc
s
ConverterSwitching
DC-AC
Transformer leakageinductance
TransformerCoupling
Series Compensation
o
X
V
I
VV
Voltage Source Converters
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Basic 6-Pulse, 2-level, Voltage-Source Converter
cec
Ta2 a2D Tb2
a
b
e
e
ai a1T
ib
i
a1 b1D T
D Tb2 c2 Dc2
dc2
V
b1 c1D T c1D
dc+Cs
V
dci
dcV
Hypotheticalneutral point
2
Voltage Source Converters
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2, 3, 5-level, VSC Waveforms
vdc2
vdc2 +
vdc2
vdc2
eout
vdc+
Neutral(mid-) point
dc+v
eout
- v dc
+ v dc
+vdc
dc+
v
Neutral(mid-) point
+vdc
dc+
v
1
2
eout
2 dcv
dcv
Voltage Source Converters
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Output voltage control of a two-level VSC
v
oFv (
ov ( )
ov ( )
*=
=) V(+ sin t)
V=oF ( ) sin(+ )
=
*
v sinV t
t
=
=
dc
t
v dc
dci
CC
t(v+v)dc
dc nominalvdcv)(v-
t
v
1dci dt
f C
dci
t (V=vo o )
0io
Vv=
Voltage Source Converters
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FACTS Technology - Possible Benefits
• Control of power flow as ordered. Increase the loading capability of lines to their thermal capabilities, including short term and seasonal.
• Increase the system security through raising the transient stability limit, limiting short-circuit currents and overloads, managing cascading blackouts and damping electromechanical oscillations of power systems and machines.
• Provide secure tie lines connections to neighboring utilities and regions thereby decreasing overall generation reserve requirements on both sides.
• Provide greater flexibility in siting new generation.
• Reduce reactive power flows, thus allowing the lines to carry more active power.
• Reduce loop flows.
• Increase utilization of lowest cost generation.
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FACTS and HVDC: Complimentary SolutionsHVDCIndependent frequency and controlLower line costsPower control, voltage control,stability control
FACTSPower control, voltage control,stability control
Installed Costs (millions of dollars)
Throughput MW HVDC 2 Terminals FACTS
2000 MW $ 40-50 M $ 5-10 M 500 MW $ 75-100M $ 10-20M1000 MW $120-170M $ 20-30M2000 MW $200-300M $ 30-50M
(*)Hingorani/Gyugyi
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FACTS and HVDC: Complimentary Solutions
Large market potential for FACTS is within the ac system on a value-added basis, where:
• The existing steady-state phase angle between bus nodes is reasonable• The cost of a FACTS device solution is lower than HVDC or other alternatives• The required FACTS controller capacity is less than 100% of the transmission throughput rating
HVDC Projects: Applications
Submarine cable
Long distance overhead transmission
Underground Transmission
Connecting AC systems of different or incompatible frequencies
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FACTS Attributes for Different ControllersFACTS Controller Control Attributes
Static Synchronous Compensator(STATCOM without storage)
Voltage control, VAR compensation, damping oscillations, voltagestability
Static Synchronous Compensator(STATCOM with storage, BESS, SMES,large dc capacitor)
Voltage control, VAR compensation, damping oscillations, transientand dynamic stability, voltage stability, AGC
Static VAR Compensator (SVC, TCR,TCS, TRS
Voltage control, VAR compensation, damping oscillations, transientand dynamic stability, voltage stability
Thyristor-Controlled Braking Resistor(TCBR)
Damping oscillations, transient and dynamic stability
Static Synchronous Series Compensator(SSSC without storage)
Current control, damping oscillations, transient and dynamic stability,voltage stability, fault current limiting
Static Synchronous Series Compensator(SSSC with storage)
Current control, damping oscillations, transient and dynamic stability,voltage stability
Thrystor-Controlled Series Capacitor(TCSC, TSSC)
Current control, damping oscillations, transient and dynamic stability,voltage stability, fault current limiting
Thyristor-Controlled Series Reactor(TCSR, TSSR)
Current control, damping oscillations, transient and dynamic stability,voltage stability, fault current limiting
Thyristor-Controlled Phase-ShiftingTransformer (TCPST or TCPR)
Active power control, damping oscillations, transient and dynamicstability, voltage stability
Unified Power Flow Controller (UPFC) Active and reactive power control, voltage control, VARcompensation, damping oscillations, transient and dynamic stability,voltage stability, fault current limiting
Thyristor-Controlled Voltage Limiter(TCVL)
Transient and dynamic voltage limit
Thyristor-Controlled Voltage Regulator(TCVR)
Reactive power control, voltage control, damping oscillations,transient and dynamic stability, voltage stability
Interline Power Flow Controller (IPFC) Reactive power control, voltage control, damping oscillations,transient and dynamic stability, voltage stability
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X
Regulating Bus VoltageCan Affect Power Flow Indirectly / Dynamically
E1 / 1 E2 / 2I P&Q
P1 = E1 (E2 . sin ())/X
FACTS Implementation - STATCOM
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Line Impedance CompensationCan Control Power Flow Continuously
E1 / 1 E2 / 2P&Q
P1 = E1 (E2 . sin ()) / Xeff
X
FACTS Implementation - TCSC
Xeff = X- Xc
The alternative solutions need to be distributed; often series compensation has to be installed in several places along a line but many of the other alternatives would put both voltage support and power flow control in the same location. This may not be useful. For instance, if voltage support were needed at the midpoint of a line, an IPFC would not be very useful at that spot. TCSC for damping oscillations ...
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X
E1 / 1 E2 / 2I
P&Q
FACTS Implementation - SSSC
P1 = E1 (E2 . sin ()) / Xeff
Xeff = X - Vinj/I
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X
E1 / 1 E2 / 2I
P&Q
Regulating Bus Voltage and Injecting Voltage In Series With the LineCan Control Power Flow
P1 = E1 (E2 . sin ()) / Xeff
Xeff = X - Vinj / I
FACTS Implementation - UPFC
Q1 = E1(E2 - E2 . cos ()) / X
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Shunt Inverter Series Inverter
Unified Power Flow Controller
Series Transformer
Shunt
Transformer
FACTS Implementation - UPFC
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X
Regulating Bus Voltage Plus Energy StorageCan Affect Power Flow Directly / Dynamically
E1 / 1 E2 / 2I
P&Q
Plus Energy Storage
FACTS Implementation - STATCOM + Energy Storage
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X
E1 / 1 E2 / 2I
P&Q
FACTS Implementation - SSSC + Energy Storage
Plus Energy Storage
Voltage Injection in Series Plus Energy StorageCan Affect Power Flow Directly / Dynamicallyand sustain operation under fault conditions
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X
E1 / 1 E2 / 2
IP&Q
Plus Energy Storage
Regulating Bus Voltage + Injected Voltage + Energy StorageCan Control Power Flow Continuously, and Support Operation Under Severe Fault Conditions (enhanced performance)
FACTS Implementation - UPFC + Energy Storage
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Shunt Inverter
Series Inverter
Unified Power Flow Controller - SMES Interface
SMES Chopper and Coil
1000μF
1000μF
1000μF
1000μF
FACTS Implementation - UPFC + Energy Storage
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SMES Chopper and Coil - Overvoltage Protection
UPFC Grounding
MOV
FACTS Implementation - UPFC + Energy Storage
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$
Regulating Bus Voltage + Energy Storage + Line Impedance CompensationCan Control Power Flow Continuously, and Support Operation Under Severe Fault Conditions (enhanced performance)
FACTS Implementation - TCSC + STACOM + Energy Storage
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E1 / 1 E3 / 3
FACTS Implementation - IPFC
P12 = E1 (E2 . sin (1- 2)) / X
E2 / 2
P13 = E1 (E2 . sin (1- 3)) / X
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Series Inverter #1 Series Inverter #2
Interline Power Flow Controller
Series Transformer, Line 2
Series Transformer, Line 1
FACTS Implementation - IPFC
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Increased Power Transfer
Enhanced Power Transfer and Stability:Technologies’ Perspective
FastReal Power Injection
and Absorption
FastReactive Power Injection
and Absorption
FastReactive Power Injection and
Absorption
CompensationDevices
FACTS DevicesEnergy Storage
Electric Grid Electric Grid
P
P AdditionalStability Margin
PTSSCSSSCUPFC
SMES
0 0.5 1 1.5 2 2.5 30
0.5
1
1.5
2
Phase Angle
Pow
er T
ransf
er
AccelerationArea
DecelerationArea
StabilityMargin
STATCOM STATCOM
TSSCSSSCUPFC
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STATCOMReactive Power OnlyOperates in the vertical axis only
STATCOM + SMESReal and Reactive PowerOperates anywhere within thePQ Plane / Circle (4-Quadrant)
P
Q
The Combination or Real and Reactive Power will typically reduce the Rating of the Power Electronics front end interface.Real Power takes care of power oscillation, whereas reactive power controls voltage.
The Role of Energy Storage: real power compensation can increase operating control and reduce capital costs
P - Active PowerQ - Reactive Power
MVA Reduction
FACTS + Energy Storage
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SMES Power (MW)
Add
itio
nal P
ower
Tra
nsfe
r(M
W)
Closer to generation
Closer to load centers
FACTS + Energy Storage - Location Sensitivity
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2 STATCOMs 1 STATCOM + SMES
Voltage and Stability Control Enhanced Voltage and Stability Control
Syst
em F
requ
ency
(H
z)
60.8
59.2
time (sec) time (sec)
(2 x 80 MVA Inverters) ( 80 MVA Inverter + 100Mjs SMES)
Syst
em F
requ
ency
(H
z)
60.8
59.2
Syst
em F
requ
ency
(H
z)
60.8
59.2
time (sec)
No Compensation
Enhanced Power Transfer and Stability:Location and Configuration Type Sensitivity
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FACTS For Optimizing Grid Investments
FACTS Devices Can Delay Transmission Lines ConstructionBy considering series compensation from the very beginning, power transmission between regions can be planned with a minimum of transmission circuits, thus minimizing costs as well as environmental impact from the start.
The Way to Proceed
· Planners, investors and financiers should issue functional specifications for the transmission system to qualified contractors, as opposed to the practice of issuing technical specifications, which are often inflexible, and many times include older technologies and techniques) while inviting bids for a transmission system.
· Functional specifications could lay down the power capacity, distance, availability and reliabilityrequirements; and last but not least, the environmental conditions.
· Manufacturers should be allowed to bid either a FACTS solution or a solution involving the building of (a) new line(s) and/or generation; and the best option chosen.
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Specifications
(Functional rather than Technical )
Transformer ConnectionsHigher-Pulse OperationHigher-Level OperationPWM ConverterPay Attention to Interface Issues and Controls
ConverterIncrease Pulse NumberHigher LevelDouble the Number of Phase-Legs and Connect them in ParallelConnect Converter Groups in ParallelUse A Combination of several options listed to achieve required rating and performance
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Technology Transmission LineTransfer Enhancement
Cost Range Operating principle ProcurementAvailability
Reconductor lines Increase thermal capacity $50K to $200K permile
Increases thermal limit for line Competitive
Fixed or Switched ShuntReactors
Voltage reduction – LightLoad Management
$8-$12 kVAR Compensates for capacitive var-load
Competitive
Fixed or Switched ShuntCapacitors
Voltage support andstability
$8-$10 kVAR Compensates for inductive var-load
Competitive
Fixed or Switched SeriesCapacitors
Power flow control,Voltage support andStability
$12-$16 kVAR Reduces inductive lineimpedance
Competitive
Static VAR Compensators Voltage support andstability
$20-$45 kVAR Compensates for inductiveand/or capacitive var-load
Competitive
Thyristor Controlled SeriesCompensation (TCSC)
Power flow control,Voltage support andstability
$25-$50 kVAR Reduces or increases inductiveline impedance
Limitedcompetition
STATCOM Voltage support andstability
$80-$100 kVAR Compensates for inductive andcapacitive var-load
Limitedcompetition
STATCOM w/SMES Voltage support andstability
$150-$300 kW Compensates for inductiveand/or capacitive var-load plusenergy storage for active power
Limited
Unified Power FlowController (UPFC)
Power flow control,Voltage support, andStability
$150-$200 kW SVC and TCSC functions plusphase angle control
Sole source
Unified Power FlowController (UPFC) w/SMES
Power flow controlVoltage support andStability,
$250-$350 kW SVC and TCSC functions plusvoltage regulator, phase anglecontroller and energy storage
Sole source
Shaded area indicates technologies that are either permanently connected or switched on or off with mechanical switches. (i.e. these arenot continuously controllable)
Cost Considerations
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Hardware
Eng & Project Mgmt.
Installation
Civil Works
Commissioning
Insurance
Cost Considerations
Cost structure
The cost of a FACTS installation depends on many factors, such as power rating, type of device, system voltage, system requirements, environmental conditions, regulatory requirements etc. On top of this, the variety of options available for optimum design renders it impossible to give a cost figure for a FACTS installation. It is strongly recommended that contact is taken with a manufacturer in order to get a first idea of costs andalternatives. The manufacturers should be able to give a budgetary price based on a brief description of thetransmission system along with the problem(s) needing to be solved and the improvement(s) needing to beattained.
(*) Joint World Bank / ABB Power Systems PaperImproving the efficiency and quality of AC transmission systems
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Technology & Cost Trends
I
$$$
$
I
additional cost savings possible
$
49P. Ribeiro June, 2002
Concerns About FACTS
Cost
Losses
Reliability
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Economics of Power Electronics
Sometimes a mix of conventional and FACTS systems has the lowest costLosses will increase with higher loading and FACTS equipment more lossy than conventional onesReliability and security issues - when system loaded beyond the limits of experienceDemonstration projects required
Cost of SystemCost of System
100% Power 100% Power Electronics Electronics
100% 100% ConventionalConventional
Delta-PDelta-P11
Delta-PDelta-P22 Delta-PDelta-P33
Delta-PDelta-P44
Stig Nilson’s paper
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Operation and Maintenance
Operation of FACTS in power systems is coordinated with operation of other items in the same system, for smooth and optimum function of the system. This is achieved in a natural way through the Central Power System Control, with which the FACTS device(s) is (are) communicating via system SCADA. This means that each FACTS device in the system can be operated from a central control point in the grid, where the operator will have skilled human resources available for the task. The FACTS device itself is normally unmanned, and there is normally no need for local presence in conjunction with FACTS operation, although the device itself may be located far out in the grid.
Maintenance is usually done in conjunction with regular system maintenance, i.e. normally once a year. It will require a planned standstill of typically a couple of days. Tasks normally to be done are cleaning of structures and porcelains, exchanging of mechanical seals in pump motors, checking through of capacitors, checking of control and protective settings, and similar. It can normally be done by a crew of 2-3 people with engineer´s skill.
Joint World Bank / ABB Power Systems PaperImproving the efficiency and quality of AC transmission systems
52P. Ribeiro June, 2002
Impact of FACTS in interconnected networksThe benefits of power system interconnection are well established. It enables the participating parties to share the benefits of large power systems, such as optimization of power generation, utilization of differences in load profiles and pooling of reserve capacity. From this follows not only technical and economical benefits, but also environmental, when for example surplus of clean hydro resources from one region can help to replace polluting fossil-fuelled generation in another.
For interconnections to serve their purpose, however, available transmission links must be powerful enough to safely transmit the amounts of power intended. If this is not the case, from a purely technical point of view it can always be remedied by building additional lines in parallel with the existing, or by uprating the existing system(s) to a higher voltage. This, however, is expensive, time-consuming, and calls for elaborate procedures for gaining the necessary permits. Also, in many cases, environmental considerations, popular opinion or other impediments will render the building of new lines as well as uprating to ultrahigh system voltages impossible inpractice. This is where FACTS comes in.
Examples of successful implementation of FACTS for power system interconnection can be found among others between the Nordic Countries, and between Canada and the United States. In such cases, FACTS helps to enable mutually beneficial trade of electric energy between the countries.Other regions in the world where FACTS is emerging as a means for AC bulk power interchange between regions can be found in South Asia as well as in Africa and Latin America. In fact, AC power corridors equipped with SVC and/or SC transmitting bulk power over distances of more than 1.000 km are a reality today.
Joint World Bank / ABB Power Systems PaperImproving the efficiency and quality of AC transmission systems
53P. Ribeiro June, 2002
Power Quality Issues
1 – Background2 – The Need For An Integrated Perspective of PQ3 – Harmonics4 – Imbalance5 – Voltage Fluctuations6 – Voltage Sags 7 – Standards, Limits, Diagnostics, and Recommendations
Flexibility, Compatibility, Probabilistic Nature, Alternative Indices8 – Combined effects9 – Power Quality Economics10 – Measurement Protocols11 – Probabilistic Approach12 – Modeling & Simulation13 – Advanced Techniques
(Wavelet, Fuzzy Logic, Neural Net, Genetic Algorithms)14 – Power Quality Programs
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Compatibility: The Key Approach
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kUref
kUrefkUkRTL ,0max
Relative Trespass Level (RTL)
Uk - measured or calculated harmonic voltage
Uref - harmonic voltage limit (standard or particular equipment)
k - harmonic order
2 4 6 8 10 12 140
2
4
6
88
0
RTL k
132 k
0 0.05 0.10
2
4
6
88
0
RTL k
.10 Uk
56P. Ribeiro June, 2002
Possible Problems
Caution SevereDistortions
DangerousLevels
NormalLevels
A B C D E F G RTL0
1
Norm
alB
elowN
ormal
Over
Heating
Very
Hot
Below
Norm
alab
cd
e
Equ
ipm
ent
Mal
fun c
t io n
Mag
nitu
de $
Ph a
se
Ang
le
Individual Harmonics (Vh)Equipment Malfunction
Fuzzy - Color Code CriteriaNo Problem
Caution
Possible Problems
Imminent Problems
Harmonic Distortion Diagnostic Index Applying Fuzzy Logic Comparisons
Alternative Approach
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How To Interpret This?
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How To Interpret This?
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Generation Delivery Conversion Processing
CentralStation
T&D AC-ACSupplies
Motion
Environmental Maintainability Availability Safety Efficiency Reliability Performance PricePower Quality
Power System Value Chain
Power Electronics Systems and Components
SMESBatteries
FACTSSMESPQ Parks
UPS Appliances
INPUTS OUTPUTS
Val
ue D
imen
sion
s
Energy Power Communication
Light / Motion
Utility User
The Total Quality Environment
60P. Ribeiro June, 2002
Conclusions
• Future systems can be expected to operate at higher stress levels• FACTS could provide means to control and alleviate stress• Reliability of the existing systems minimize risks (but not risk-free)• Interaction between FACTS devices needs to be studied• Existing Projects - Met Expectations• More Demonstrations Needed• R&D needed on avoiding security problems (with and w/o FACTS)• Energy storage can significantly enhance FACTS controllers performance
61P. Ribeiro June, 2002
Conclusions
A Balanced and Cautious Application
The acceptance of the new tools and technologies will take time, due to the computational requirements and educational barriers.
The flexibility and adaptability of these new techniques indicate that they will become part of the tools for solving power quality problems in this increasingly complex electrical environment.
The implementation and use of these advanced techniques needs to be done with much care and sensitivity. They should not replace the engineering understanding of the electromagnetic nature of the problems that need to be solved.
62P. Ribeiro June, 2002
Questions and Open Discussions