98年 中華電信招考 專業職(四)第一類專員 電力類 電機工程 試卷

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3
2.
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250 MCM
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100 mm
2
3
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100 W
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100V
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200 W
100 W
50 W
25 W
2
4.
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RS
TUVW
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2
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Z[PQ
(load factor)
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(average load)
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(peak load)
9ab
cPQ
(demand factor)
-^"c
(average demand)
d ec
(peak demand)
9ab
f g P Q
(loss factor)
-^ " D E f g
(average power loss)
_ ` Z [ hD E f g
(power loss at peak load)
9 a b
ijPQ
(diversity factor)
-)kdec9Cl
(sum of individual maximum demand)
mJdec
(coincident maximum demand)
9ab
4
6.
nopqSrs9tu
@qSp,vab
@qSp,wxy+b
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2
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(
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20sin 377 90
i t t
= °
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
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90
°
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3
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(
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(
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800 1000cos 754 36.87
p t t
:&&apos;
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60 Hz
<opZ[-
20 36.87
°
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(
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3
9.
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0.8
(leading)
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1600
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600
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1800
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10.
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(per unit system)
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old
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old
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V
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new
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new
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new
pu
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new new
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pu pu
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+
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+ +
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= °
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(generator bus)
³e´µ¶-+b
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(load bus)
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(P)
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(effective resistance)
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16.
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aS
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aS
(CT)
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1
17.
®qS
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(copper loss)
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4
18.
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(kVA
b
)
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(kV
b
)
25kV
¤çê
22kV
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R
(kVA
b
)
.
(kV
b
)
.
(kA
b
)
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(Z
b
)
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2
19.
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ò ô
õöë÷ø
óôë÷ø
ù
1
20.
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(balanced delta system)
$
(line current)
üý¬
3
þp
(phase current)
2
þp
p
p3
3
1
21.

a
.
b
-FG
4 V
6 V
7.5 V
10 V
2
22.

a
.
b
Òü
(V
TH
)
ë
(Z
TH
)
k-FG
V
TH
= 10 V
Z
TH
= 9
V
TH
= 10 V
Z
TH
= 2
V
TH
= 9 V
Z
TH
= 2
V
TH
= 9 V
Z
TH
= 6
2
23.
2
R
 b -
3
: ß
R
 -F G
1 A
2 A
3 A
4 A
4
24.
n®L
±Y
TUVW
,XVY
1
25.
-6)9deVY9UÎK¬
Ñ
(subtransient reactance,
d
X
)

(transient reactance,
d
X
)
,X
(synchronous reactance,
d
X
)
«p©
(zero-sequence reactance,
0
X
)
3
26.
ªp^¢9®±hH «p©
o$
(bolted single line-to-ground fault)
($
(bolted double line-to-ground fault)
ªp
(bolted three phase-to-ground fault)
o$ë($ÓÅ
(bolted single line-to-ground and line-to-line fault)
2
27.
DEk-
10 kW
.
11kW
ë
15kW
DEPQ"-
0.8
O6ª)Z[ ÊqS
!y<ª)Z[
(connected loads)
mJcPQ
(demand factor)
-
0.6
:<ÊqS@
cd´;DE*+-FG
22 kVA
27 kVA
45 kVA
75 kVA
4
28.
"#$%&&apos;()*:×Ê$9*+&&apos;
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×$ÅÛ$Å;&U+,0--./3 ³
×$Å1,2$Å.34ü30 --./ 3³-5:
×$Å1,6743---./ 3³-5:
3
29.
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;*+
:Å"H<=>9?(JH<>9ª
:Å"H<=>9?(JH<>9?
:Å"H<=>9ª(JH<>90
:Å"H<=>9ª(JH<>9@
4
30.
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

20
)


~ªpRSG
(three-phase capacitor bank)
9HpI
6
¹
200-kvar
.
2770-V
.
60-Hz
9opRSo
J
(single-phase capacitor units)
GKªpL] H
Y
û $
(floating wye connected)
Á
4.16-kV
.
60-Hz
MN
OP;<Qu<ªpRSGåDE*+b
(actual reactive power
rating)
O


@¥-ARÊo$ O-ST¡U V @Jub"W X Y O
ÓÅR-
250 MVA
ZiQ¨OP 3
Fault
± ªpÓÅ
h
Fault
9 C ëÓÅRO
6
3
2

8
4
6
4
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