AC Stalling Simulations (1)
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Transcript of AC Stalling Simulations (1)
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AC Stalling Computer
Simulations usingEMTDC/PSCAD
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* EMTDC/PSCAD Model of the SCE 500 kV System andValley 115 kV System
* Computer model development and validation againstShort Circuit Program, Digital Fault Recorders (DFR)captured disturbances and PMU events
* SCE 500 kV System bus voltages after clearing faults onat SCE 500 kV buses computer simulations
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THE EMTDC/PSCAD MODEL
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SCE 500kV PSCAD SYSTEM MODEL
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VALLEY (500 and 115 kV) SYSTEM PSCAD MODEL
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THE PSCAD MOTOR LOAD AT VALLEY 115/12kV
* Air Conditioning Motor electrical characteristics from reference [1]
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THE 500kV SYSTEM MOTOR LOAD
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MODEL DEVELOPMENT
Generate a short circuit model reduction from CAPE software usingSCE protection engineering data base
Setting up initial conditions using PSLF load flow by adjusting thesource equivalent voltage and angle
System validation by comparing short circuit results between CAPEand PSCAD models
Comparing actual captured faults from DFR records and PMUevents
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SHORT CIRCUIT SOURCE EQUIVALENT USING CAPE
MODEL REDUCTION
BUS X+ R+ Z+ Angle+ X0 R0 Z0 Angle0
(Ohms) (Ohms) (Ohms) (deg) (Ohms) (Ohms) (Ohms) (deg)
Vincent 2.94 51.92 51.999 86.759 0.83 24.80 24.816 88.090
Lugo 0.84 17.63 17.647 87.275 2.11 24.10 24.193 84.993
Mira Loma 1.14 39.87 39.888 88.356 0.27 22.48 22.477 89.315
Serrano 1.69 48.44 48.471 88.004 1.15 26.21 26.235 87.492
Valley 23.84 1207.79 1208.022 88.869 1.90 52.39 52.421 87.927
Devers 6.51 96.74 96.963 86.151 0.07 44.92 44.918 89.908
Palo Verde 0.32 6.91 6.920 87.385 0.24 5.10 5.107 87.346
The PSCAD model is designed based on a reduced network model fromCAPE (Protection Engineering Short Circuit Program).
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INITIAL CONDITIONS (STEADY STATE) FROM LOAD
FLOW PROGRAM PSLF
Voltage Voltage Angle
BUS P (MW) Q(MVAR) P Q (p.u.)* (kV) (degrees)
(p.u. on 100MVA) (p.u. on 100 MVA)
VINCENT 1618.2 83.6 16.182 0.836 1.044 522 -13.982
LUGO 3736.1 338.4 37.361 3.384 1.035 517.5 -18.792
MIRA LOMA -3071.2 -195.6 -30.712 -1.956 1.024 512 -26.297
SERRANO -1556.7 263 -15.567 2.63 1.029 514.5 -29.219
VALLEY -1465.6 -79 -14.656 -0.79 1.028 514 -32.836
DEVERS -754.1 283.8 -7.541 2.838 1.038 519 -28.687
PALO VERDE 1587.5 266.1 15.875 2.661 1.07 535 -3.843
The initial conditions maybe take from a load flow program. In our casethe PSLF load flow is used as the initial condition for the PSCADsimulations.
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THE VALIDATION PROCESS
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SHORT CIRCUIT VALIDATION CAPE VR. PSCAD
A well know method to validate EMTP-type model is to compare theShort Circuit results between the EMTP type program (PSCAD) andShort Circuit program (CAPE)
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VALIDATION AGAINST STATION DFR DISTURBANCE
(faults in the Valley 115 kV system)
SLG Fault on the secondary of Valley 2AA bank cleared inapproximately 3 cycles
-3
-2
-1
0
1
2
3
60 80 100 120 140 160 180
Valley 500/115 kV Tranformer Bank Current
Electrotek Concepts TOP, The Output Processor
agntue
ag
Time (ms)
DFR Record PSCAD Simulation
SLG Fault on 115kV Valley system at 115kV Skylard-Newcomb line
cleared in 6 cycles
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
50 100 150 200
Valley 2AA Tranformer Bank Current
Electrotek Concepts TOP, The Output Processor
MagnitueMag
Time (ms)
DFR PSCAD
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JULY 1, 2006 DISTURBANCE FROM PSCAD AND DFR
(fault at the 500 kV System)
Fault on the Devers-Palo Verde 500 kV transmission line 20 milesapproximately from California Caps on the Arizona side captured byDevers DFR.
-15
-10
-5
0
5
10
15
50 100 150 200
DEVERS - PALO VERDE PHASE A
Electrotek Concepts TOP, The Output Processor
Magnitude(kMag
Time (ms)
DEVERS DFR PSCAD
-20
-10
0
10
20
60 80 100 120 140 160 180
DEVERS PALO VERDE PHASE C CURRENT
Electrotek Concepts TOP, The Output Processor
Magnitude(kMag
Time (ms)
DFR PSCAD
To Devers To Palo Verde
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HOW DO THESE FAULTS IMPACT THE REST OF THE500 kV SYSTEM?
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FAULTS AND THE IMPACT OF THE 500 kV SYSTEM
The question may be answered by comparing the magnitude of the voltages fromthe PMU record before and after the fault is cleared. The in between points (duringfault) maybe more of a challenge but we will discuss it in a few slides later.
Pre-Fault
Post-Fault
During the fault
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LOAD FLOW FROM PMU DATA
In order to setup the initial conditions to the PMU load flow the PMU BusVoltages and Angles are utilized instead of the PSLF
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PRE-FAULT BUS VOLTAGES PSCAD VR. PMU(J uly 1, 2006 Disturbance)
Pre-Fault PSCAD vr. PMU Bus Voltages
400
420
440
460
480
500
520
540
560
Vincent 500kV Valley 500kV Lugo 500 kV Mira Loma 500 kV Serrano 500 kV
Voltage (kV)
PMU
PSCAD
Snap shot (voltage profile) of the SCE 500 kV system bus voltages before thedisturbance from the PMU and PSCAD
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POST-FAULT BUS VOLTAGES PMU VR. PSCAD
(July 1, 2006 Disturbance)
Post-Fault B us Voltage PMU vr. PSCAD
300
350
400
450
500
550
Vincent 500kV Valley 500kV Lugo 500 kV Mira Loma 500 kV Serrano 500 kV
Voltage (kV)
PMU
PSCAD
Snap shot (voltage profile) of the SCE 500 kV system right after the fault is clearedfrom the PMU and PSCAD
3.5% error difference
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WHAT ABOUT DURING THE FAULT?
During the fault as before mentioned we have to be careful when comparing thecomputer simulation to the actual PMU record. The PMU samples at 30Hz and inorder to look at the PSCAD simulation the PSCAD recorder has to be set of sampleat the same rate or the result may show a great difference. We must understand thatthe main purpose of the PMU is to look at slow time frame disturbance and not fast
transients.
Simulation is kept at small step
Plot at smaller step
PSCAD Recordersame as PMUSampling rate
COMPARING DATA PSCAD AND PMU AT SAME
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COMPARING DATA PSCAD AND PMU AT SAMESAMPLE RATE
As show on the plots below the bus voltage magnitudes are closely correlatedbefore, during and after the fault is cleared
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REMEMBER THE PMU BUS MAGNITUDE AT DEVERSDURING THE FAULT WENT TO ZERO?
CONVERTING DFR RECORD INSTANTANEOUS BUS VOLTAGE
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WAVEFORMS TO POSITIVE SEQUENCE MAGNITUDE
Using a Matlab-Simulink developed tool the instantaneous values from the DFRrecord are converted to positive sequence magnitude (similar to PMU but fartersampling rate)
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PSCAD SIMULATION VR. DFR RECORD
DFR Record
PSCAD Simulation
So lets compare it now to what our PSCAD simulation results show. On the plotbelow we compare the PSCAD simulation with a sample rate of 50 us to the DFRrecord positive sequence from Devers magnitude.
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System Fault versus Motor Stalling
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1 2 3 4 56 7 8 9 10 11 12 13 14 15 16 17
18S1
S3
S5
0.00
0.20
0.40
0.60
0.80
1.00
1.20
Voltage (Per Unit)
System Voltage After Clearing Fault
1.00-1.20
0.80-1.00
0.60-0.80
0.40-0.60
0.20-0.40
0.00-0.20
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Motor Speed on All 500 kV Buses
R l d R ti P
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LUGO : Motor Load LUGO
0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80
0
25
50
75
100125
150
175
200
RealPower(M
W)
Pmot_lug
-100
0
100
200
300
400
500
600
700
ReactivePower(MVAR
)
Qmot_lug
Real and Reactive Power
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FUTURE WORK
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ANY QUESTIONS?
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* IEEE Transactions in Power Systems Air ConditioningResponse to Transmission Faults: J ohn W. Shafter, May
1997
* IEEE Transactions in Power Systems Motor Load
Dynamics: Impact on Voltage Recovery PhenomenaGorge K. Stefopous, Georgia Tech, 2006.
References