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2
(Coupled) 2
1. (Power Transformer)
2. (Variable Frequency Transformer)
“ ”
”
(Coil) (Ferromagnetic Core)
2 (Primary Winding)
(Secondary Winding)
2.1
1 50
.1885
William Stanley ( .1858-1916) 2.1
2.1
( )
(Lenz’s Law) (Faraday’s Law)
2.2
2.2 Coil 1
Coil 2
“
”
Coil 2
1 1 (+)
Coil 1 ( )
( )
1.8 1
2 51
= = (Volt) (2.1)
2.2
(Volt) (2.2)
2.2
-
( 2.1)
2.2 1
(Primary Winding)
(Secondary Winding) 1 2.3
2.3 1
2.3
(Leakage Flux)
1 2 Core-type
Shell-type 2.4 2.5
1 52
2.4 1
(Laminated Core)
Core-type L 2.5 .
Shell-type E I 2.5 .
. Core-type
. Shell-type
2.5 1
HV
LV
LV
HV
2 53
2.3
2.6
2.6 .
(Exciting Current ; )
2 - 5% ( 5% )
Mutual
Flux ( )
Primary =
2.6 . ( )
( = )
2.1 ( )
+, - (Dot, )
(+) (-) ( ) + 2.6
1 54
2.4
2.7
(Ideal Transformer)
(No Load Test)
(Open Circuit Test)
(Short Circuit Test)
2 55
2.5
2.8
2.8 . (Leakage Flux)
= +
=
1 1.8
1 1.8 ( 1.20)
= , = (2.3)
1 56
. . 1.21 1
.
2
( ) Core-loss
Current Magnetizing Current
2.8 .
= + , = , = , = + (2.4)
cos (Power Factor ; )
(Core Loss ; )
= = = = (2.5)
2.1 2.8 . ( ) 264
( ) 220 50
Leakage Flux
. ( ) 25 .
( )
. ( ) 50 W, Apparent Power [S, (VI)rms] 500 VA
Exciting Current ( ), Core-loss Current ( ), Magnetizing Current ( )
.
. = 25 cm
= = 220 V
2.3 ; = 2 =
= 2
= 2 = 220 2 (264)(50)(25 × 10 ) = 1.5 T
= .
2 57
. , , = 50 W, ( ) = 500 VA
2.8 . 2.8 .
= ( ) = = 2.273 A
= , = = = 0.2273 A
= = 2.273 0.2273 = 2.262 A
=( )
= = 0.1
= . , = . , = . , = .
.
= =.
= 968 , = =.
= 97.3
= , = .
2.6
(Transfer)
Leakage Flux
1 58
2.9
2.3
= = 2 ……………….. (1)
= = 2 ……………….. (2)
( )( )
; = = = …………………. (3)
Turn Ratio Voltage Ratio
2.9 .
2.9 . + + = 0
( = 0) =
= ……………………………… (4)
(3) (4)
2 59
= = = = (2.6)
2.6 Referred
2.6 ; = =
( ) = ( ) (2.7)
Referred Referred
(Impedance ; ) (Admittance ; )
2.10 Referred
2.10 Referred
. Referred
.
2.10 . ; = , =
2.6 ; = , =
= = =
= (2.8)
Referred Referred
Referred
1 60
= (2.9)
Referred
2.8, 2.9 ,
Referred , Referred 2.10
= , = (2.10)
2.7
(Polarity)
(Dot, )
1 3
2.11
2.11 ( ) . ( 1
3 ) 2 4 ,
2 61
1
3 (+) ( ) .
( ) ( )
.
.
(Subtractive Polarity)
= | | (2.11)
2.12
2.12 ( ) . ( 1
4 ) 2 4 ,
1 4
(+) ( ) .
( ) ( )
.
.
(Additive Polarity)
= | + | (2.12)
1 62
2.11 2.12
2.13
2.13 2 4
1
,
1. = | | ( ) 3 (
2.11)
2. = | + | ( ) 4 (
2.12)
1
2.14
( ) .
2.14
2 63
2.8
(Practical Transformer)
2.15
N2
.
+
-
+
-
+
-V1 E1 E2
+
-V2Load
Ideal Transformer
.
l1 l2
+
-
E1
+
-
+
-
V2
+
-
V1
R2R1 X l1 X l2
Primary Secondary
Primary Secondary
R c1 X m1
Im1Ic1
I
E2
I 2
I2
I 1
N : N or E : E or a1 21 2
m
N1
I 1 I 2
2.15
,
(Reactance) Leakage Flux
(Reactance) Leakage Flux
, Referred
(Ideal Transformer)
1 64
Referred
Referred , Referred
,
2.15 . Referred
2.16
Ideal Transformer
+
- a
+
-
V2
+
-
V1
R1 X l1
Primary Secondary
X l2 R2
V2
R c1 X m1
Im1Ic1
I I 2I2I 1
. Referred
Ideal Transformer
+
-a
+
-
V2
+
-
V1
Primary Secondary
I 2I 1
. Referred
R1 X l1 R2X l2
I1
Ic2 Im2
R c2 X m2
V1
I
2.16 Referred
2 65
2.15 . Referred (Parameter) -
Referred ,
2.16 .
Referred 2.8
= , =
2.15 . Referred (Parameter) -
Referred , ,
, 2.16 .
Referred 2.10
= = , = =
= , =
2.2 (Distribution Transformer)
50 kVA, 2200 220 V, 50 Hz (HV) 0.75 + 0.95
(LV) 0.007 + 0.009 = 310 + 44.6
(Referred LV)
. Referred HV
. Referred LV
= 2200 220 = 10
1 66
. Referred HV
Referred 2.8
+ = ( + ) = 10 (0.007 + 0.009) = 0.7 + 0.9
= =
= ( + ) = 10 (310 + 44.6) = (31 + 4.46) × 10
. Referred LV
Referred 2.10
+ = ( + ) = (0.75 + 0.95) 10 = 0.0075 + 0.0095
2 67
2.9
2.8 Referred
2.16
T-Circuit
(Approximate Equivalent Circuit)
Referred 2.16 .
2.17 .
( , ) 2.17 .
+
-
+
-
V1
R1 X l1 X l2 R2
V2R c1 X m1
Im1Ic1
I I 2I 1
. Referred
+
-
+
-
V1
R1 X l1 X l2R2
V2R c1
Im1Ic1
II 2
I 1
. , Xm1R c1 V1
X m1
2.17
1 68
2.17 . 2.18 . + = , + = , + =
(Equivalent Resistance) Referred
(Equivalent Reactance) Referred
(Equivalent Impedance) Referred
.
.
2.18 Referred
2.19 Referred
2.19 Referred
2 69
2.10
2.18 .
2.19 .
Referred ( 2.18 .)
Referred ( 2.19 .)
2.10.1
(No Load Test, Open Circuit
Test) ( )
, 2.20 .
+
-
. .
Primary Secondary
Transformer
WA
VVoc
IocPoc
P = Pc oc
Voc
Ioc
R c1 X m1
Y
2.20
2.20 . ( )
( )
( , , )
, .
1 70
.
= , = , = (2.13)
= , =
2.10.2
(Short Circuit Test)
, Referred
, 2.21 .
2.21
2.21 .
, , ,
.
= , = , = (2.14)
2 71
2.3 1 10 kVA, 200 1000 V, 50 Hz
= 0.04 + 0.3 (Referred )
1000
. = 1 . = 0.8
= 200 1000 = 1 5
( ) = 1000 V, ( ) = , ( ) = 10000 1000 = 10 A
= = (1000) = 200 V, = = = = 50 A
. = 1
= cos ( ) = cos 1 = 0° = 1000 0° V, = 10 0° A = 200 0° V, = 50 0° A
1 Complex Number
= + + = 200 0° + (0.04 + 0.3)(50 0°)
= 200 + 2 + 15 = 202 + 15 = 202.56 4.25° V
= .
2 Phasor Diagram
Phasor Diagram
= + + = + +
1 72
V2
V1
R eq1I2
I 2 Xeq1
I 2
= (50)(0.04) = 2 V
= (50)(0.3) = 15 V
Phasor Diagram
= + + = (200 + 2) + (15) = 202.56 V
= .
. = 0.8
= cos ( ) = cos (0.8) = 36.87°
= 1000 0° V, = 10 36.87° A
= 200 0° V, = 50 36.87° A
1 Complex Number
= + + = 200 0° + (0.04 + 0.3)(50 36.87°)
= 200 + (0.3027 82.41°)(50 36.87°) = 200 + 15.135 45.54°
= 200 + 10.6 + 10.802 = 210.6 + 10.802 = 210.88 2.94°
= .
2 Phasor Diagram
Phasor Diagram
= + +
Req1
I2
2 73
= cos = (50)(0.04) cos 36.87° = 1.6
= = sin = (50)(0.04) sin 36.87° = 1.2
= = sin = (50)(0.3) sin 36.87° = 9
= cos = (50)(0.3) cos 36.87° = 12
Phasor Diagram
= ( + + ) + ( )
= (200 + 1.6 + 9) + (12 1.2) = 210.88 V
= .
2.4 1 50 kVA, 2200 220 V, 50 Hz
= 0.0272 + 0.0348 (Referred )
= 0.9
(Feeder) 1.68 + 3.12
2200
= 2200 220 = 10
Referred Feeder
= = = 10 (0.0272 + 0.0348) = 2.72 + 3.48
1 74
+
-
a = 10
1.68 + j3.12 +
-
Load
Primary Secondary
V2
I 1
I 2I 2Feeder
(2200 V) 0.9 Leading
2.72 + j3.48Vs V2
+
-
Req1 Xeq1
a = 10
+
-
Load
Primary Secondary
V2
I 2I 2
0.9 Leading
4.4 + j6.6
V2
+
-
+
-
I 1
(2200 V)Vs
R X
( ) = 220 V, ( ) = , ( ) = 50000 220 = 227.3 A
= = (10) , = 10, = = = . = 22.73 A
= cos ( ) = cos (0.9) = 25.84°
= 0° V, = 227.3 25.84° A
= 0° V, = 22.73 25.84° A
1 Phasor Diagram
Phasor Diagram
= + +
2 75
= cos = (22.73)(4.4) cos 25.84° = 90
= = sin = (22.73)(4.4) sin 25.84° = 43.6
= = sin = (22.73)(6.6) sin 25.84° = 65.4
= cos = (22.73)(6.6) cos 25.84° = 135
= ( + ) + ( + )
(2200) = ( + 90 65.4) + (43.6 + 135) = ( + 24.6) + (178.6)
= (2200) (178.6) 24.6 = 2168 = 10 = 2168 10 = 216.8 V
= .
2 Complex Number
= + + , = 0° + ( + ) 25.84°
2200 = 0° + (4.4 + 6.6)(22.73 25.84°)
2200 = 0° + (7.932 56.31°)(22.73 25.84°)
2200 = 0° + 180.294 82.15°
2200 cos + 2200 sin = ( + 24.625) + 178.6
+ 24.625 = 2200 cos ………………………….. (1)
2200 sin = 178.6 ………………………………………. (2)
(2) ; sin = 178.6 2200 , = 4.66°
(1) ; + 24.625 = 2200 cos 4.66° , = 2168
= 10 = 2168 10 = 216.8 V
= .
1 76
2.11 Voltage Regulation
Voltage Regulation
(
) Voltage Regulation
2.22 Voltage Regulation
% = , ,
,× % (2.15)
,
,
2 77
2.22 . Referred
% = , ,
,× 100%
2.22 . = 0 = 0
, = % Voltage Regulation 2.16
% = | | ,
,× % (2.16)
2.16 % Voltage Regulation | |
2.22 . (Locus)
PF + = 0
% Voltage Regulation PF
Lagging PF ( ) )
% Voltage Regulation PF (cos )
% Voltage Regulation ±5%
% Voltage Regulation PF 2.23
2.23 %Voltage Regulation PF
1 78
2.5 1 10 kVA, 2200 220 V, 50 Hz
= 10 + 30 (Referred )
( , ) 220 % Voltage Regulation
. 80% = 0.6
. = 0.6
= 2200 220 = 10
. 80% = 0.6
= (0.8) (10 × 10 ) 2200 = 3.636 A
= cos ( ) = cos (0.6) = 53.13°
= = (10)(220) = 2200 V
= 0° = 2200 0°, = 53.13° = 3.636 53.13°
= + + = 2200 0° + (10 + 30)(3.636 53.13°)
= 2200 0° + 36.36 53.13° + 109.08 90° 53.13°
= 2200 + 21.816 29.089 + 87.264 + 65.448
= 2309.08 + 36.359 = 2309.37 0.9°
= 2309.37 V
% = | | ,
,× 100% = . × 100% = 4.97%
% = . %
2 79
. = 0.6 = (10 × 10 ) 2200 = 4.545 A
= cos ( ) = cos (0.6) = 53.13°
= = (10)(220) = 2200 V
= 0° = 2200 0°, = 53.13° = 4.545 53.13°
= + + = 2200 0° + (10 + 30)(4.545 53.13°)
= 2200 0° + 45.45 53.13° + 136.35 90° + 53.13°
= 2200 + 27.27 + 36.36 109.08 + 81.81
= 2118.19 + 118.17 = 2121.48 3.19°
= 2121.48 V
% = | | ,
,× 100% = . × 100%
3.57%
% . %
2.12
( -
) (Efficiency ; )
95%
= × % = × % (2.17)
2.24 Referred
1 80
2.24
= ( ) 2.25 .
= 2.25 .
= cos
= × % (2.18)
2.25 .
. .
2.25
2.12.1
2.25
( )
= = cos
=( )
= 0 = 0 =
c
cu
2 81
( )
2.19 = 2.25 .
= = , , (2.19)
= =
= ( ) ( )
= 0 sin = 0, = 0°
= cos 0° = 1
( )
2.20
= , , (2.20)
=
=
2.6 1 10 kVA, 2200 220 V, 50 Hz
(Referred ) = 100 W
80% PF = 0.6 Lagging
1 82
= %%
( ) ( ) = (0.8)(10000) 220 = 36.36 A
= %%
( ) ( ) = %%
(10000)(0.6) = 4800 W
= 100 W
= = 36.36 (0.104) = 137.5 W
= × 100% =.
× 100% = 95.29%
= . %
2.12.2
(All-day Efficiency ; ) (Energy)
24
(%Load)
= × % (2.21)
(kWh) ( kW)
( hr)
% = ( )( )
× 100% =,
× 100%,,
= %%
= %%
( ) ( )( )
= +
24 = ( )(24 )
= ( )( ) = ( ) = ,
,( )
= ,
,( ) =
,, ( )
= %% , ( )
2 83
2.7 1 50 kVA, 2200 220 V, 50 Hz
= 200 W = 500 W
24
% 0% 50% 80% 100% 110%
1 0.8 0.9 1
6 8 5 3 2
( )
24 = (50)(1)(8) + (50)(0.8)(5)
+ (50)(0.9)(3) + (50)(1)(2)
= 605 kWh
24 = (0.2 )(24 ) = 4.8 kWh
24 = (0.5)(8) + (0.5)(5)
+ (0.5)(3) + (0.5)(2)
= 5.31 kWh
24 = 4.8 + 5.31 = 10.11 kWh
= × 100%
=.
× 100% = 98.36%
= . %
1 84
2.13
(Autotransformer)
2.26
2.26
= = = , = (2.22)
( )
2.8
2 85
2.8 1 2 100 kVA, 2000 200 V
kVA
= = 2000 V, = + = 2200 V
= = 100 × 10 2000 = 50 A
= = = 100 × 10 200 = 500 A
= + = 50 + 500 = 550 A
= = (2000)(550) = 1100 kVA
= = (2200)(500) = 1100 kVA
= =
kVA 100 kVA
2.8 kVA 1100 kVA
1 86
2.14 Per-unit
Per-unit (Per-unit ; pu)
(Base, Reference)
= ( ) (2.22)
Per-unit
1.
2. Referred
)
Per-unit 1
1 2.1
2.1 1
, , = = 1
, = = 1 , = = 1
, =,
= 1 , =,
= 1
, = ,
,= , = 1 , = ,
,= , = 1
Referred Referred
, = , = , , , = , = ,
, = , = , , , = , = ,
, = , = , , , = , = ,
2 87
, ,
= , , = ,
, =,
, , =,
=,
=,
, = , Referred
Referred
, = , , , = , , , = , , , = , , = , , , = ,
Per-unit 100
2.9 1 10 kVA, 2200 220 V, 50 Hz
= 10 + 30 (Referred )
.
.
. 80% = 0.6 -
% Voltage Regulation
= 2200 220 = 10
. , , = = 10 kVA, , = = 2200 V
, = , = = 484
1 88
, =,
= = 0.02066 + 0.062
.
, = , = , = 1
, = , , = (1) (0.02066) = 0.02066
= , = (0.02066 )(10000) = 206.6 W
, = . , = .
, = ,
. 80% = 0.6 -
% Voltage Regulation
, = , = 1, , = , = , = 0.8
= cos ( ) = cos (0.6) = 53.13°
, = 1 0°, , = 0.8 53.13°
, = , + , , = 1 0° + (0.02066 + 0.062)(0.8 53.13°)
= 1 + 0.01653 53.13° + 0.0496 36.87°
= 1 + 0.00992 0.01322 + 0.03968 + 0.02976
= 1.0496 + 0.01654 = 1.04973 0.9°
% Voltage Regulation ( 2.16)
% = | | ,
,× 100% = , , ,
, ,× 100%
= . × 100% = 4.97%
% = . % 2.5 .)
2 89
2.15 3
3 120°
2 (Star, Wye ; Y) (Delta ; )
2.27 .
2.27
, , 120°
.
= = =
, , 120°
. 3
= = = = 3
30° . 30°
30° 30°
1 90
2.28 .
A
C B
VABVABVCA VCA
C
A
BVBC
VBC
. .
2.28
, ,
120°
= = = =
3 1 3
( 3
1 3 3
3
3 3
1.
2. Y
3. 1
58% Open-delta (V )
4. Y 3
2 91
2.15.1
. .
A
C
B
a
b
c
A
a b c
B C
A
B
C
a
bc
VAN
VBN
VCN
VABVCA
N
CC
AA
B BVBC
VAB
30
. . .
N
Vab
Vbc
Vca Vab
a
b
c
V2V1
I
aIV
V3 V
3 a
3 aI
2.29
3 Voltage Ratio 2 ( , )
( ) Voltage Ratio Voltage Ratio 1
2.29 . ( )
= =
= = 3 = 3
= ( ) (2.23)
1 92
Referred 3
Referred Voltage Ratio ( , ) Referred
Voltage Ratio ( )
Referred Voltage Ratio
Voltage Ratio Referred
2.29 .
30° Polarity 2.29 .)
2.15.2
. .
A
C
B
a
b
c
A
a b c
B C
A
B
C
a
bc
VAB
VCA
C
A
BVBC
VAB
30
. . .
n
Vab
Vbc
Vca
Vaba
bc
V2V1
I
V I3 V
a
aI3
aI3
3 Va
Van
Vbn
Vcn
a
c b
n
2.30 Y
2 93
2.30 . ( )
= =
= = 3 = 3
= ( Y) (2.24)
2.30 .
30° ( Polarity 2.30 .)
2.15.3
2.31
1 94
2.31 . ( )
= =
= = =
= ( ) (2.25)
2.31 .
( Polarity 2.31 .)
2.15.4
. .
A
C
B
a
b
c
A
a b c
B C
A
B
C
a
bc
VAN
VBNVCN
VABVCA
N
CC
AA
B BVBC
VAB
. . .
N
Vbc
Vca
Vab
a
b c
V2V1
I aI
V
V3
V3 a
n
Va
a
c
Vab
b
Van
VbnVcnn
2.32 Y
2 95
2.32 . ( )
= =
= = 3 3 =
= ( Y) (2.26)
2.32 .
Polarity 2.32 .)
2.15.5 Referred
Referred 3 1
2 Referred Referred
1. Referred Voltage Ratio -
( ) Referred
2. Referred Voltage Ratio -
( ) Referred
.
A
B
C
a
b
c
. Referred
A
B
C
a
b
c
Z eq2Z eq2
Z eq2Z L
Z L
Z L
Z eq1
Z eq1
Z eq1
Z L
Z L
Z L
2.33 Referred 3
Voltage Ratio ; = =
Voltage Ratio ; = = 3
1 96
2.15.6
3
(Y)
( )
. .3
2.34 Y
= (2.27)
2.15.7 3
3 1
3
3
2 Core-type Shell-type
1. Core-type
Core-type 2.35 1 Core-
type 3 .
, , 120° + + = 0
. B
. .
2 97
. .
. .
2.35 3 Core-type
2. Shell-type
Shell-type 1 Shell-type 3
2.36
2.36 3 Shell-type
1 98
1 Shell-type
2.36 2.37 Shell-type 5-leg
2.37 3 Shell-type 5-leg
2.2 3
Connection Connection
Voltage Magnitude = 3 =
Current Magnitude = = 3
Apparent Power (S) VA = 3 = 3
Active Power (P) W = 3 cos = 3 cos
Reactive Power (Q) VAR = 3 sin = 3 sin
Equivalent Y (Balanced Phase) = 3
3-phase Y Transformer = 3 , , , , 30°
3-phase Y Transformer = 3, , , , 30°
3-phase , Y Y Transformer = , , ,
Polarity 30° 0°, 30°, 150°, 180°,
330° Vector Group)
2 99
2.10 1 40 kVA, 2400 240 V
= 1.83 (Referred )
3 3
Feeder 3 -
= 0.8 /phase ( Feeder) Feeder
3 , 500 kVA, 24000 2400 V( )
= 2.76 /phase (Referred )
24000 V( )
3 240 V ( )
Feeder 2400 V 2400 240 V
240 V
.
2400 V 24000 V 240 V
24000 V
j0.8
j0.8
j0.8
I1 I4I3
I2
j1.83
j1.83
j1.83j2.76
j2.76
j2.76
Trans.1Trans.2
.
Trans.1 = = 2400 240 = 10
Y , = 1.83 3 = 0.61
Trans.2 = 24000 2400 = 10
Y , = 2.76 3 = 0.92
1 100
.
2400 V 24000 V 240 V
24000 V
j0.8
j0.8
j0.8
I1 I4I3
j0.61j0.92
Trans.1Trans.2
j0.61
j0.61j0.92
j0.92
2400 V N
.
j2.33
I1
0 V0 V
0 V
.
2400 V3
2400 V3
Trans.2 24000 2400 V( )
24000 V( ) 2400 V( ) Y
2400 3 V .
Feeder 2400 V Y 2 Neutral (
) Neutral
0.92 + 0.8 + 0.61 = 2.33 .
= 2400 3 2.33 = 594.7 A
, , .
= 3 = 594.7 3 = 343.35 A
= = (10)(343.35) = 3433.5 A
= 3 = 3(3433.5) = 5947 A
= . , = . , = . , =
2 101
2
1. ( ) 55
( ) 220 ( ) 2
Leakage Flux
. , Core-loss Current ( ) Magnetizing Current ( )
.
. = 0.125 , = 0.25 A, = 1.984 A
. = 880 , = 110.9
2. 1 100 kVA, 220 1100 V, 50 Hz
(LV) 0.011 + 0.031 (HV) 0.25 + 0.75
= 440 + 260 (Referred LV)
. Referred HV
. Referred LV
+
-
+
-
V2
+
-
V1
R1 X l1 X l2 R2
V2
R c1
Primary (LV) Secondary (HV)
0.011 + j0.031 0.01 + j0.03
Xm1
a = 1/5
440 + j260
.
.
1 102
3. 1 440 220 V, 50 Hz
Test Voltage (V) Current (A) Power (W)
Open Circuit 220 2.5 100 220 V
Short Circuit 30 22.75 209.1 440 V
. Referred . Referred
. .
4. 1 10 kVA, 2400 240 V, 50 Hz
= 6 + 30 (Referred )
= 0.8
240 % Voltage Regulation
2347.8 2.81° V, 2.175%
5. 1 24 kVA, 2400 240 V, 50 Hz
= 6 + 30 (Referred )
= 1
2400 % Voltage Regulation
232.12 V, 3.4%
2 103
6. 1 500 kVA, 2300 230 V, 50 Hz
= 0.174 + 0.4 (Referred HV)
= 2351 + 246 (Referred HV) = 1
HV 2300
1137 A, 98.3%
7. 1 10 kVA, 2400 240 V, 50 Hz
= 100 W = 240 W
24
% 0% 70% 90%
0.8 0.9
6 10 8
( )
95.93%
8. 4 pu (Referred
) 4 % Voltage
Regulation 4
2.175%
1 104
9. 1 440 110 V 3 3 Y
Feeder 3 = 1.6 /phase (
Feeder) (Resistive
Load) (Line) 50
= 0.5 (Referred )
Feeder 432 V( )
173.76 V( )
10. 1 2200 220 V 3 3
Feeder 3 = 2 /phase (
Feeder) R-L (Line)
433 218 V( )
Feeder 3880 V( ) = 0.01
(Referred )
PF
0.606
11. 1 10 kVA, 1330 230 V 3 3
Feeder 3 = 0.8 +
5 /phase Feeder 3 = 0.003 +
0.015 /phase 3 27 kVA, 0.9
230 V( ) = 0.12 + 0.25
(Referred )
Feeder
2437 V( )