al-owied voltage stabilty pdf
DESCRIPTION
voltage stability pdfTRANSCRIPT
![Page 1: Al-Owied voltage stabilty pdf](https://reader031.vdocument.in/reader031/viewer/2022032705/55cf91ff550346f57b928756/html5/thumbnails/1.jpg)
1
EE 306
TRANSFORMERS
Instructor:
Dr. Mahamed Shwehdi
Done By:
Ahmad Saleh Al-Owied
![Page 2: Al-Owied voltage stabilty pdf](https://reader031.vdocument.in/reader031/viewer/2022032705/55cf91ff550346f57b928756/html5/thumbnails/2.jpg)
2
Transformers
Very large three-phase network transformer.
![Page 3: Al-Owied voltage stabilty pdf](https://reader031.vdocument.in/reader031/viewer/2022032705/55cf91ff550346f57b928756/html5/thumbnails/3.jpg)
3
Transformer electromagnetic device (mutual induction)electromagnetic device (mutual induction)
1. components:-- 2 adjacent coils
-- coils not physically connected to each other
![Page 4: Al-Owied voltage stabilty pdf](https://reader031.vdocument.in/reader031/viewer/2022032705/55cf91ff550346f57b928756/html5/thumbnails/4.jpg)
4
Transformer (cont.)
2. operation:a) AC in primary coil produces B
b) Secondary coil receives a in I & V
N
SN
SN
SN
SN
SN
S
![Page 5: Al-Owied voltage stabilty pdf](https://reader031.vdocument.in/reader031/viewer/2022032705/55cf91ff550346f57b928756/html5/thumbnails/5.jpg)
5
Transformers
N n
A
B
C
a
b
c
IA Ia
VANVAB
VCN
VBN Vbn
Van
Vcn
Vab
Wye / Wye connection
![Page 6: Al-Owied voltage stabilty pdf](https://reader031.vdocument.in/reader031/viewer/2022032705/55cf91ff550346f57b928756/html5/thumbnails/6.jpg)
6
Transformers
LoadSupplyNetwork
Transformer
Y-Y
Three-phase network supplies a load through a transformer.
Transformer LoadSupply Network
Xtr_s
Van Vload_anVAN
Vnet_ANXnet
IAIa
N
n
A
a
Xtr_s
Van Vload_anVAN
IAIaVnet_AN
Xnet
Equivalent circuit of the wye-wye
Single-phase equivalent circuit for phase A of the three-phase wye-wye transformer system
![Page 7: Al-Owied voltage stabilty pdf](https://reader031.vdocument.in/reader031/viewer/2022032705/55cf91ff550346f57b928756/html5/thumbnails/7.jpg)
7
Wye / Delta connection
A
B
C
N
VANVAB
VBN
VBC
VCN
IA
Iba
Icb
VCA
a
b
c
a
b
c
Ia
Ic
IbVab
Vbc
Vca
Iac
![Page 8: Al-Owied voltage stabilty pdf](https://reader031.vdocument.in/reader031/viewer/2022032705/55cf91ff550346f57b928756/html5/thumbnails/8.jpg)
8
Transformers
Ia
Ib
Ic
Vab
Vbc
VcaVCN
VBN
VAN
A
B
C
a
b
c
Icb
Iba
Iac
Transformer
AC
AC
AC
IC
IB
IA
VAN
VBN
VCN
Supply
Iab
Ibc
Ica
Load
VAB
VBC
VCA
Iac
Vca
Vbc
Vab
N
Wye-delta connected transformer
![Page 9: Al-Owied voltage stabilty pdf](https://reader031.vdocument.in/reader031/viewer/2022032705/55cf91ff550346f57b928756/html5/thumbnails/9.jpg)
9
Transformers
Single-phase equivalent circuit of a wye-delta transformer.
Xtr_s
Van Vs_anVAN
IA Ia
Vp_AN
Xtr_pRtr_p Rtr_s
XmRc
Tspe
Y-
![Page 10: Al-Owied voltage stabilty pdf](https://reader031.vdocument.in/reader031/viewer/2022032705/55cf91ff550346f57b928756/html5/thumbnails/10.jpg)
10
Delta / Wye connection
A
B
C
n
a
b
cVBC
IaIA
Ib
Ic
VAB
VCA Vca
Vab
Vbc
Van
Vbn
Vcn
IC
IBICA
IAB
IBC
![Page 11: Al-Owied voltage stabilty pdf](https://reader031.vdocument.in/reader031/viewer/2022032705/55cf91ff550346f57b928756/html5/thumbnails/11.jpg)
11
Delta / Delta connection
A
B
C
a
b
c
VAB
Ia
Iba
Iac
IA
IAB
ICA
Vab
![Page 12: Al-Owied voltage stabilty pdf](https://reader031.vdocument.in/reader031/viewer/2022032705/55cf91ff550346f57b928756/html5/thumbnails/12.jpg)
12
Transformers
Transformer Connection
Primary and Secondary Voltage Phase Relation
Phase Shift*Windings Placed on the Same
Leg
Wye-Wye VAN is in phase with Van Zero A and a
Wye-Delta VAN is in phase with Vab 30° A and ab
Delta-Wye VAB is in phase with Van –30° AB and a
Delta-Delta VAB is in phase with Vab Zero AB and ab
* Note: Phase shift lead between line-to-line voltages, VAB and Vab, and line-to-neutral voltages, VAN and Van,
and line currents, IA and Ia.
Three-phase Transformer Relations
![Page 13: Al-Owied voltage stabilty pdf](https://reader031.vdocument.in/reader031/viewer/2022032705/55cf91ff550346f57b928756/html5/thumbnails/13.jpg)
13
Transformer Turns Ratio ratio of the # of turns in the
secondary coil to the # of turns in the primary coil P
S
N
NTR
numerical factor indicating relative change in PD across a transformer
TR > 1 = V (step up)TR < 1 = V (step down)
![Page 14: Al-Owied voltage stabilty pdf](https://reader031.vdocument.in/reader031/viewer/2022032705/55cf91ff550346f57b928756/html5/thumbnails/14.jpg)
14
Transformer Law (change in voltage in a transformer) in V is directly proportional to the ratio of the
# of turns in the secondary to the # of turns in the primary
Formula: NN
VV
S
P
S
P
=NS secondary coil turnsNP primary coil turns
VS secondary voltageVP primary voltage
direct relationship
![Page 15: Al-Owied voltage stabilty pdf](https://reader031.vdocument.in/reader031/viewer/2022032705/55cf91ff550346f57b928756/html5/thumbnails/15.jpg)
15
Transformer Current
Current in a transformer will be inversely proportional to the TR of the transformer
formula: NN
II
S
P
P
S
=
VV
II
S
P
P
S
=
IP primary coil currentIS secondary coil current
I vs. V = inverse relationship
![Page 16: Al-Owied voltage stabilty pdf](https://reader031.vdocument.in/reader031/viewer/2022032705/55cf91ff550346f57b928756/html5/thumbnails/16.jpg)
16
Types of Transformers Based on TURNS RATIO
2. step-down turns ratio < 1VS < VP
IS > IP
1. step-up turns ratio > 1VS > VP
IS < IP
![Page 17: Al-Owied voltage stabilty pdf](https://reader031.vdocument.in/reader031/viewer/2022032705/55cf91ff550346f57b928756/html5/thumbnails/17.jpg)
17
Transformer Types (cont.) Based on STRUCTURE OF COILS
1. air core -- inside area of coil is
empty
-- inefficient induction
2. open core-- ferromagnetic
material inside coils
-- B = induction
![Page 18: Al-Owied voltage stabilty pdf](https://reader031.vdocument.in/reader031/viewer/2022032705/55cf91ff550346f57b928756/html5/thumbnails/18.jpg)
18
Transformer Types (cont.)
3. closed core-- ferromagnetic ends
connected-- induction
4. shell -- lazy square eight-- overlap of coils on
same ferromagnetic core