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課程名稱︰電力工程導論
課程性質︰電機系複選必修
課程教師︰劉志文
開課學院：電資學院
開課系所︰電機系
考試日期（年月日）︰2010/11/11
考試時限（分鐘）：120 mins
是否需發放獎勵金：是 謝謝
（如未明確表示，則不予發放）
試題 :
Introduction to Power Engineering
Midterm exam 2010/11/11
1. Please List 5 kinds of primary energy. (5%)
2. Please list 5 kinds of renewable energy. (5%)
3. State the Theorem of Conservation of Complex Power in terms of mathematical
formula. (10%)
4. What is balanced three-phase system? Pleasse explain it. (10%)
5. A single phase load draws 10kW from a 416-V line at a power factor of 0.9
lagging.
(a) Find S = P+ jQ (5%)
(b) Find |I| (5%)
6. If a straight infinitely long wire of radius r has uniform current density
in the wire and total current i, then calculate the flux linkages inside
the wire. (10%)
7. Calculate the inductance per meter of each phase of a three-phase
transmission line(Fig.1). Assume that
1. Conductors are equally spaced D, and have equal radii r. (5%)
2. ia+ib+ic=0 (5%)
Fig.1 -> 請見課本P.63 Fig. E3.2
8. A 60-Hz 138-kV 3Φ transmission line is 200 km long.the distributed line
parameters are
r = 0.15 Ω/km
l = 2 mH/km
c = 0.012 uF/km
g = 0
The transmission line delivers 40MW at 132kV with a 95% power factor
lagging. Finding the sending-end voltage and current.
Find the transmission line efficiency. (10%)
[Hint]: Zc = √(z/y), γ = √(z*y), z = r + jωl, y = g + jωc
V(x) = V2cosh(γx) + Zc*I2sinh(γx),
I(X) = I1cosh(γx) + V2/Zcsinh(γx),
where V2, I2 are receiving-end voltage and current.
9. In Fig. 2, assume that V1 = 1∠0度
Fig. 2 -> 請見課本P.103 Fig. 4.4
Pick QG2 so that |V2| = 1. In this case what are QG2, SG1 and ∠V2? (10%)
10.Consider the following system shown in Fig. 3. In the transmission system
all the shunt elements are capacitors with an admittance Yc = 0.01j, while
all the series elements are inductors with an impedence of Zc = 0.1j.
Find:
(a) Ybus matrix (5%)
(b) power flow equations. You don't need to solve the equations.
Just list equations. (5%)
Fig. 3 -> 請見課本P. 347 Fig. E10.6
11.Use the Newton method to solve
f1(x) = (x1)^2 + (x2)^2 - 1 = 0
f2(x) = (x1) + (x2) = 0
With an initial guess " 0" = 1 and " 0" = 0. Do two iterations. (10%)
x x
1 1
//""裡 0和1分別是x的上標與下標
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