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Reactive Power Compensation - PTD H16M - Rev. 1.0 1
Tutorial on Static Var CompensatorsSan Francisco, June 12, 2005
Presented by:Heinz Tyll
Rajiv K. VarmaHubert Bilodeau
Chris Horwill
Prepared by:Hubert Bilodeau
Michael BahrmanChris Horwill
Peter LipsHeinz Tyll
Rajiv K. Varma
Reactive Power Compensation - PTD H16M - Rev. 1.0 2
Tutorial on Static Var CompensatorsSan Francisco, June 12, 2005
OUTLINE
Module 1 - Reasons for reactive power compensation
Module 2 - Basic characteristics of SVC
Module 3 - SVC configurations and implications
Module 4 - Main components in existing installations
Module 5 - Thyristor valves
Module 6 - Regulation, Control and Protection system
Module 7 - Commissioning
Module 8 - Standards
Module 9 - References
Reactive Power Compensation - PTD H16M - Rev. 1.0 3
Transmission Line CharacteristicsReceiving End Voltage during Power Transfer
Line constants: x’, r’, c’, g’VS VR
S=P+jQTransmission Line
Sending end Receiving end
PSIL = Surge impedance loadingExample: 200 km line with no lossesEffect of capacitive and inductive loading
Reactive Power Compensation - PTD H16M - Rev. 1.0 4
Voltage Profile along a Long Transmission Line
Reactive Power Compensation - PTD H16M - Rev. 1.0 5
Voltage Profile along a Long Transmission Line with Midpoint Reactive Power Compensation
Reactive Power Compensation - PTD H16M - Rev. 1.0 6
Power System Improvements with Var Control:Influence of a Reactive Power Compensator
Reactive Power Compensation - PTD H16M - Rev. 1.0 7
Voltage Stability
Normal System Conditions – 2000 MVA Short Circuit
n-1 Contingency – 1500 MVA Short Circuit Level
Voltage stability limits power transferAdequate stability margin required for contingenciesInadequate reactive power reserve risks voltage collapseDynamic voltage support via SVC permits higher power transfer
Reactive Power Compensation - PTD H16M - Rev. 1.0 8
Increased Transfer with Dynamic Voltage Support
n-1 Contingency – 1500 MVA Short Circuit Level
Maximum power flow depends on network and voltage supportSteady state voltage via slow devices, e.g., switched capacitors, tap changersDynamic reactive power reserve required for contingencies Improved post-contingency voltage profile due to SVC dynamic reactive support
Reactive Power Compensation - PTD H16M - Rev. 1.0 9
SVC Applications in LV Transmission Systems
Power factor correctionImprovement of load voltageDecrease of transmission system losses
to be added to power plant installationsto be added to operating costs
Load balancingSymmetrisation of system voltage
Reactive Power Compensation - PTD H16M - Rev. 1.0 10
SVC Applications in HV Transmission Systems
Voltage controlImprovement of system voltage regulationunder varying load conditions
Increase in steady state power transfer capacity
Enhancement in transient stability
Prevention of voltage instability
Augmentation of system damping
Improvement of HVDC link performance
Reactive Power Compensation - PTD H16M - Rev. 1.0 11
Voltage Control: Voltage in the Systemfor Various Operating Conditions
a Heavy load
b Light load
c Outage of 1 line(at full load)
d Load rejectionat bus 2
System Conditions:Load
SVC
230 kV - 300 km
V2V1
Grid
1.2
1.1
1.0
0.9
0.8
ba c d
without SVC
with SVCV2
V2N
Reactive Power Compensation - PTD H16M - Rev. 1.0 12
Increase in Steady State Power Transfer Capacity: Comparison of different limits of power flow
Reactive Power Compensation - PTD H16M - Rev. 1.0 13
The problems of distance & variable load
0 MW Ferranti Effect
400kV
Target 800MW Natural Load
1000MW System Collapse
400kV400kV
800MWGeneration
800MWLoad
400kV
Power
400kV
400kV Transmission Line (uncompensated)
Length of Line
800 km
Reactive Power Compensation - PTD H16M - Rev. 1.0 14
The problems of distance & variable load
400kV400kV
1000MWGeneration
1000MWLoad
400kV
1000MW
400kV
SVCSVC
800 km
400kV
Target 1000MW Increased capacitydue to SVC
Shunt Compensated Line
Length of Line
Reactive Power Compensation - PTD H16M - Rev. 1.0 15
Power Oscillation Damping (POD) with SVC
SVC
G1
P1, δ1Infinite bus
• If d(∆δ)/dt or ∆f is positive, i.e. rotor is accelerating due to built up kinetic energy, the FACTS device is controlled to increase generator electrical power output
• If d(∆δ)/dt or ∆f is negative, i.e. rotor is decelerating due to loss of kinetic energy, the FACTS device is controlled to decrease generator electrical power output
• Modulation of SVC bus voltage required through auxiliary signals
Reactive Power Compensation - PTD H16M - Rev. 1.0 16
Two - Area study system (cont’d)
Three-phase fault is introduced in one of the transmission lines between bus 8 and bus 9
Oscillations caused:
• Local rotor mode oscillations• Inter- machine rotor mode oscillations• Inter- area oscillations are associated with swinging of
two machines in area 1 against the other two machinesin area 2.
Reactive Power Compensation - PTD H16M - Rev. 1.0 17
Static Var Compensator (SVC)Damping of Power Oscillations (POD)
Reactive Power Compensation - PTD H16M - Rev. 1.0 18
Improvement of HVDC Link Performance with SVC
Voltage regulation
Support during recovery from large disturbances
Suppression of temporary over voltages
Reactive Power Compensation - PTD H16M - Rev. 1.0 19
Static Var Compensator (SVC)Typical SVC Configuration
LV bus bar
Fixed filter circuit
Thyristor controlledreactor
Thyristor switchedcapacitor
Control
Step-down transformer
HV
LV
Reactive Power Compensation - PTD H16M - Rev. 1.0 20
Static Var Compensator (SVC)Common Configurations (1)
TCR, FC TSR, TSCTCR, TSC, FC
Reactive Power Compensation - PTD H16M - Rev. 1.0 21
Static Var Compensator (SVC)Common Configurations (2)
3AC 60Hz 138 kV
SN = 150 MVA, uk = 10 %
CF1
3AC 60Hz 14.3 kV
STF 1
LF1
TCR 1
LTCR12
LTCR12
3AC 60Hz 14.3 kV
STF 2
LF2
TCR 2
LTCR22
LTCR22
Reactive Power Compensation - PTD H16M - Rev. 1.0 22
Static Var Compensator (SVC)Loss Comparison
0.4
Reactive Power Compensation - PTD H16M - Rev. 1.0 23
Main Components of an SVC
Transformer TSC FilterTCR
Reactive Power Compensation - PTD H16M - Rev. 1.0 24
SVCs Centrals, NGC, UK 275 kV, 150 c / 75 i MVar
Reactive Power Compensation - PTD H16M - Rev. 1.0 25
SVCs Centrals, NGC, UK 275 kV, 150 c / 75 i MVar
Reactive Power Compensation - PTD H16M - Rev. 1.0 26
SVC Pelham, NGC, UK 400 kV, 150 c / 75 i MVar
Reactive Power Compensation - PTD H16M - Rev. 1.0 27
SVC Pelham, NGC, UK 400 kV, 150 c / 75 i MVar
Reactive Power Compensation - PTD H16M - Rev. 1.0 28
Natal SVCs, Eskom, South AfricaDouble stacked air core reactor
Reactive Power Compensation - PTD H16M - Rev. 1.0 29
SVC Brushy Hill, NSPC, CanadaFilter Branches
Reactive Power Compensation - PTD H16M - Rev. 1.0 30
SVC Mead Adelanto, LADWP, USA Capacitor banks (externally fused)
Reactive Power Compensation - PTD H16M - Rev. 1.0 31
Static Var Compensators (SVC) Filter Capacitor Bank (internally fused)
Reactive Power Compensation - PTD H16M - Rev. 1.0 32
Thyristor Valve Cooling
IS
Major producers of heat losses are thyristors and snubber resistorsThyristor losses are determined by the forward voltage in the on state and the switching losses during turn on and turn offSnubber losses result from the charging current of the snubber capacitors
Reactive Power Compensation - PTD H16M - Rev. 1.0 33
Thyristor Triggering & Monitoring Approaches
chec
k-ba
ck s
igna
l
optic
al tr
igge
r sig
nal
elec
tric
al g
ate
puls
e
ETT
Valve Base Electronic(valve control)with LED
TCU
check-backauxiliary power
logicelectric gate pulse
protective gate pulse
voltage detection
chec
k-ba
ck s
igna
l
optic
al g
ate
puls
e
Valve Base Electronic(valve control)with laser
LTT
voltage detection
Reactive Power Compensation - PTD H16M - Rev. 1.0 34
Auxiliary Powerfor Triggering (Gating) of Thyristors
Typical gate pulse for ETT hasduration of 10 µspeak power of 50 W
Energy is extracted from power circuit at each level
Typical gate pulse for LTT hasduration of 10 µspeak power of 40 mW
Energy is provided by light pulse from ground level
Reactive Power Compensation - PTD H16M - Rev. 1.0 35
LTT Light Path
Reactive Power Compensation - PTD H16M - Rev. 1.0 36
Thyristor Valve Control and Monitoring
VALVE BASEELECTRONIC
I/O UNITS
MV SWITCHYARD
DIGITAL FAULTRECORDER
I/O UNITS
HV SWITCHYARD
I/O UNITS
TRANSFORMER
I/O UNITSCONTROL SYSTEM
MONITORINGPLANT CONTROL
CLOSED LOOPCONTROL
Industrial Ethernet
Process Fieldbus
AUXILIARYSUPPLY
I/O UNITS
COOLING SYSTEM
I/O UNITS
PROTECTIONSYSTEMI/O UNITS
DISPATCH CENTER
GATEWAYEXT. DEVICESV/Q CONTROL
PROTECTION(DIGSI, OSCOP, etc.)
WinCC REMOTE(HMI)
WinCC LOCAL(HMI)
TIMESYNCHRONISATION
GPS RECEIVER
SVC CONTROLROOM
SVC CONTROLROOM
SUBSTATIONCONTROL ROOM
SWITCHYARD
GPS
TSC/TCR
VALVE BASEELECTRONIC
PLANT CONTROL
CLOSED LOOPCONTROL
WinCC LOCAL(HMI)
TSC/TCRVALVE
GPS
TIMESYNCHRONISATION
GPS RECEIVER
Process Fieldbus
Industrial Ethernet
SWITCHYARD
SVC CONTROLROOM
SUBSTATIONCONTROL ROOM
Reactive Power Compensation - PTD H16M - Rev. 1.0 37
LTT Thyristor Module for SVC Valve
The module is a mechanical building block for the three phase valve setup
Reactive Power Compensation - PTD H16M - Rev. 1.0 38
SVC Control, Monitoring and Protection
Station Control Hierarchies
Devices or High-Voltage Equipment in SwitchyardLocal control of devices or SVC ControlSubstation ControlDispatch Center Control
Reactive Power Compensation - PTD H16M - Rev. 1.0 39
SVC Control, Monitoring and Protection
LOCAL (HMI)
VALVE BASEELECTRONIC
I/O UNITS
MV SWITCHYARD
DIGITAL FAULTRECORDER
I/O UNITS
HV SWITCHYARD
I/O UNITS
TRANSFORMER
I/O UNITSCONTROL SYSTEM
MONITORINGPLANT CONTROL
CLOSED LOOPCONTROL
Industrial Ethernet
Process Fieldbus
AUXILIARYSUPPLY
I/O UNITS
COOLING SYSTEM
I/O UNITS
PROTECTIONSYSTEMI/O UNITS
DISPATCH CENTER
GATEWAYEXT. DEVICESV/Q CONTROL
PROTECTION
TIMESYNCHRONISATION
GPS RECEIVER
SVC CONTROLROOM
SVC CONTROLROOM
SUBSTATIONCONTROL ROOM
SWITCHYARD
GPS
TSC/TCR
REMOTE (HMI)
Reactive Power Compensation - PTD H16M - Rev. 1.0 40
SVC Control, Monitoring and Protection
SVC Control
Plant control and monitoringClosed-loop control or RegulationValve Base ElectronicProtection system
Reactive Power Compensation - PTD H16M - Rev. 1.0 41
Static Var Compensator (SVC)Plant control
SVC Station Control and Monitoring can be divided into:
Sequence control Operator's or Human Machine Interface (HMI))Local Area Communication (LAN)Time Synchronism and distributionsSequence of events and event recording (SER)Digital fault recorderI/O from switchyard
Reactive Power Compensation - PTD H16M - Rev. 1.0 42
Static Var Compensator (SVC)Plant control
Typical functions of sequence control
SVC ON/OFF Sequence
Auto-Reclosing
Emergency Shutdown
Remote Control Function (that may include SCADA interface)
Manual and automatic switchyard control
Degraded control modes
Reactive Power Compensation - PTD H16M - Rev. 1.0 43
Static Var Compensator (SVC)Plant control
The SVC can only be energized if the status of critical systems is confirmed such as:
Cooling System On-Line and no abnormal flow or temperature conditionsInterlocks in ready statePrimary voltage measurement system synchronized and readySwitches in closed positionCLC ready and synchronizedValve Firing System ready and valves blockedTransformer cooling normalPlant Control in proper configuration (local, remote etc.)Relay systems set and no lock-out functions detected
Reactive Power Compensation - PTD H16M - Rev. 1.0 44
Static VAr Compensator (SVC)Voltage Control
Vsource
Znetwork
TCR TSCFC
LV
Control Regulator
XsSlope
+
-1/sTi-
SystemVoltage
Evaluation
HV
TSC Controller TCR/TSRController
POWER SYSTEM
VRESP
VREF
BSVC
BREF
VT
α
Distribution Unit
VBUS
∆V-
BSVC
Reactive Power Compensation - PTD H16M - Rev. 1.0 45
Static Var Compensator (SVC)Additional control functions
POD control
Q control
Gain control
Stability control
Voltage symmetrisation
Reactive Power Compensation - PTD H16M - Rev. 1.0 46
Static Var Compensator (SVC)Further Options
Degraded mode
Var management
Test mode
Redundancy
Reactive Power Compensation - PTD H16M - Rev. 1.0 47
Control and RegulationControl loop Analysis
SVCNETSOURCERESPBUS IZVVV ×−==
The SVC control loop linking the regulator to the power system canbe represented as shown
Vsource
Znetwork
Control Regulator
XsSlope
+
-1/sTi-
SystemVoltage
Evaluation
HVPOWER SYSTEM
VRESP
VREF BREF
VT
VBUS
∆V-
Valve
Bsvc
BSVC
Slope Xs
V Primary
VSOURCE
VREF
Isvc
NetworkZnet
Vresp
BSVC
Vsource
Znetwork
Control Regulator
XsSlope
+
-1/sTi-
SystemVoltage
Evaluation
HVPOWER SYSTEM
VRESP
VREF BREF
VT
VBUS
∆V-
Valve
Bsvc
BSVC
Slope Xs
V Primary
VSOURCE
VREF
Isvc
NetworkZnet
Vresp
BSVC
Reactive Power Compensation - PTD H16M - Rev. 1.0 48
Control and RegulationControl loop Analysis
Control Regulator
XsSlope
+
-1/sTi
VRESP
VREF
BREF
∆V
BSVC
ZNETWORK
Valvee -sTd
IsvcVsource-Vresp-
+
Vsource
Vresp-Vref
-
+
IsvcZnetVrespVsource ×=−
Reactive Power Compensation - PTD H16M - Rev. 1.0 49
Module 7 Commissioning an SVC
The commissioning processPrecommissioning testsSystem and operational considerationsCommissioning testsStandards and guides
Reactive Power Compensation - PTD H16M - Rev. 1.0 50
Basic steps in the commissioning process
Pre-commissioning testsTests on plant and sub systemsComplete before energising SVC at high voltage
Commissioning testsCorrect operation of the SVC designPerformance to specificationSVC performs correctly on the system
Acceptance by the purchaser
Reactive Power Compensation - PTD H16M - Rev. 1.0 51
Precommissioning tests
Tests on individual items of plant to be done in an agreedwayInterNational Electrical Testing Association (NETA), www.netaworld.org
Produces documentation on test methods and record sheets (Acceptance Testing Specifications)Certifies testing companies and technicians
Equipment not covered by NETA documentation is tested to manufacturer’s own test sheets by the manufacturer
Reactive Power Compensation - PTD H16M - Rev. 1.0 52
Precommissioning tests
Purpose of pre-commissioning testsCheck that equipment is undamagedElectrical tests to confirm rating plate detailsChecks on installation
–Cabling–Connections–Insulation resistance
Functional checksGrounding resistance check
Reactive Power Compensation - PTD H16M - Rev. 1.0 53
Precommissioning tests
Tests to be done on the largest possible sub-systemswithout making equipment aliveTests to be witnessed by the purchaser’s representativewhere possibleComplete test results accepted by the purchaserTest results presented with a master document, listing all test sheets for each equipment
Proceed to the next stage
Reactive Power Compensation - PTD H16M - Rev. 1.0 54
Safety
Safety rules covering live plantOSHA regulationsPurchaser’s safety rulesQualification of Vendor’s personnel
Reactive Power Compensation - PTD H16M - Rev. 1.0 55
Effect on system
Test program to be agreed in advanceProgram should give details of each testTest program should state Mvar output for each testLimitations on SVC output during testing
Determined from studies by the purchaserLimits may vary with time of day or day of the weekGenerators may be dispatched during some tests
Reactive Power Compensation - PTD H16M - Rev. 1.0 56
Operational matters
Personnel qualified to switchSwitching jurisdictionLiaison with control centerTest schedule to accompany the test program
Control center can plan system reconfiguration
Reactive Power Compensation - PTD H16M - Rev. 1.0 57
Commissioning tests
Detailed test program containsStep by Step details for each testMeans of recording test resultsMvar outputs
Connect recording equipmentStage by stage testing
Reactive Power Compensation - PTD H16M - Rev. 1.0 58
Commissioning tests Stage 1
Tests to confirm that the SVC has been designed correctlyEnergise all equipmentPass current in manual controlTest in automatic controlCooling plant checksHarmonic measurements
Reactive Power Compensation - PTD H16M - Rev. 1.0 59
Commissioning tests Stage 2
Tests to confirm that the SVC has met the performance specification
System harmonic measurementsVoltage/current characteristicsSpeed of responseRFI measurementsAcoustic noise measurements
Reactive Power Compensation - PTD H16M - Rev. 1.0 60
Commissioning tests stage 3
Tests to ensure that the SVC performs correctlyCapacitor and reactor switching testsAutomatic switchgear controlTemperature rise testsTrial operation periodOperation during disturbancesService experience
Reactive Power Compensation - PTD H16M - Rev. 1.0 61
Service experience
Extension of commissioning testsMonitoring of service experience may last until the endof the warranty period
Commissioning test program does not normally includestaged faultsDFR and SER at the SVC installation used to gatherperformance data
Reactive Power Compensation - PTD H16M - Rev. 1.0 62
Standards and Guides
IEEE 1303 : 1994. IEEE Guide for Static Var CompensatorField TestsCIGRE Document WG38-01 Task Force 2. Static Var Compensators, Chapter 6
Reactive Power Compensation - PTD H16M - Rev. 1.0 63
SVC DesignFunctional Specification IEEE 1031
03_03 240203
Reactive Power Compensation - PTD H16M - Rev. 1.0 64
SVC DesignField Tests for Static Var Compensator IEEE 1303
03_03 240203
Reactive Power Compensation - PTD H16M - Rev. 1.0 65
SVC DesignTest Standard for thyristor valves IEC 61954
03_03 240203