Voltage Sag
Voltage Sag
Voltage Sag
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I. INTRODUCTION
Noviembre 2 7, 28 y 29
Medelln Colombia
2013
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Medelln Colombia
2013
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Fig. 3. Typical zero sequence open circuit impedance for core-type and shelltype transformers.
The zero-sequence magnetizing impedance of three-legcore transformers of Fig. 3 (a) is a notable exception. This low
impedance, as shown in the figure, is a direct result of the core
construction. When a set of three-phase windings is excited by
zero-sequence current, the three fluxes are forced out of the
iron core to return through the air or oil where the magnetic
permeability is much smaller than that of iron. For this reason
the transformer tank can be treated as a fictitious tertiary
winding connected in delta. We have said that the engineer
should consider the modeling of zero-sequence magnetizing
impedance of three-leg-core transformers if high accuracy is
desired. Some programs, as the one used in this work, provide
a field for this parameter as a part of the model, as the B and
mainly B0 indicated in Fig. 4.
Noviembre 2 7, 28 y 29
Medelln Colombia
Fig. 6. Transformer model dialog box of the program used for the simulations
with checking of Zps0 in wye-wye-delta transformers indicating possible
anomaly.
2013
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Noviembre 2 7, 28 y 29
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Fig. 7. Voltage sag process with faults applied tiers around the monitored bus
bus faults and transmission line intermediate faults.
Vb (pu)
Vb (deg)
0
0
1,45907
0,497507
0,071485
0,508471
0,588221
0,861981
0,093324
0,630863
0,61563
0,867458
0,082384
0,581782
0,599478
0,864765
0,104785
0,664995
0,631644
Vc (pu)
0
0
-172,063
149,251
-150
-170,963
-115,471
-178,373
-156,291
-176,493
-127,143
-177,68
-153,641
-175,131
-122,309
-178,023
-158,394
-176,95
-130,644
0
0
1,39841
0,497507
0,071485
0,071485
0,995014
0,071485
0,093324
0,093324
0,995014
0,093324
0,082384
0,082384
0,995014
0,082384
0,104785
0,104785
0,995014
2013
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Vc (ang)
0
0
113,783
149,251
90
90
89,2506
90
83,7088
83,7088
89,2506
83,7088
86,3586
86,3586
89,2506
86,3586
81,6061
81,6061
89,2506
Fig. 8. Voltage sag output table with the voltage level at the monitored bus
when bus faults and transmission line intermediate faults are applied around it.
33.kV 27
0.926p.u.
BUS 21
33.kV 21
0.750p.u.
BUS 25
33.kV 25
0.851p.u.
BUS 22
33.kV 22
0.669p.u.
BUS 23
33.kV 23
0.833p.u.
BUS 13
33.kV 13
0.601p.u.
BUS 14
33.kV 14
0.685p.u.
BUS 16
13.8kV 16
0.000p.u.
BUS0
33.kV
0.071p.u.
BUS 24
33.kV 24
0.928p.u.
BUS 20
33.kV 20
0.408p.u.
BUS 26
132.kV 26
0.677p.u.
BUS 15
33.kV 15
0.425p.u.
BUS 19
33.kV 19
0.392p.u.
BUS 17
33.kV 17
0.093p.u.
BUS 10
33.kV 10
0.579p.u.
BUS 18
33.kV 18
0.105p.u.
US
1
32.kV 1
736p.u.
BUS
9
33.kV 9
0.139p.u.
BUS 29
BUS 30 13.8kV 29
13.8kV 30 0.727p.u.
0.726p.u.
BUS
3
132.kV 3
0.711p.u.
BUS
132.kV
0.636p
BUS
6
132.kV 6
0.460p.u.
BUS
4
132.kV 4
0.578p.u.
BUS
2
132.kV 2
0 692
BUS
5
132.kV 5
0 818p
BUS
7
132.kV 7
0.752p.u.
Fig. 9. Voltage sag output on a one-line diagram with the voltage level at the
monitored bus indicated on the faulted buses.
Noviembre 2 7, 28 y 29
Medelln Colombia
REFERENCES
[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
2013
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Noviembre 2 7, 28 y 29
Medelln Colombia