課程名稱︰電力工程導論
課程性質︰電機系選修
課程教師︰許源裕
開課學院：電機資訊學院
開課系所︰電機工程學系
考試日期（年月日）︰2017/11/06
考試時限（分鐘）：120(?)
試題 :
1. Given the balanced three-phase 60Hz system shown below, find v1(t). (15%)
https://i.imgur.com/HkfjhyD.jpg
2. Given the balanced three-phase 60Hz system shown below, compute the complex
power loss due to the line impedence Za. (15%)
https://i.imgur.com/NDBllc1.jpg
3. Consider the 345kV, 60Hz, completely transposed balanced three phase lines
as shown below. the radius of each subconductor is 1cm.
(a) Find the per phase inductance in H/m. (5%)
(b) Find the per phase capacitance to neutral in F/m. (5%)
(c) Assume that the line resistance is negligible. find the three phase load
power which gives flat voltage profile, i.e., |V(x)| = |V_R| (load voltage)
for any x. (5%)
a b c
○ ○ ○↖0.1m
○○ ○○ ○○ ↘
├─6m─┼─6m─┤
4. Find the magnetic field energy per unit length of conductor stored inside a
straight infinitely long wire of radius r = 1cm. Assume that the conductor
current is 100A and the skin effect can be neglected. The relative
permeability of the conductor is assumed to be 1. (15%)
5.
https://i.imgur.com/JNBBb5p.jpg
Let |V1| = 1.05, |V2| = 1, θ12 = θ1 - θ2.
(a) Depict the power circle diagram with P12 as the abscissa and Q12 as the
ordinate (0≦θ12≦2π). (5%)
(b) Find the radius and center of the power circle. (5%)
(c) Find the maximum value for P12. (0≦θ12≦2π) (5%)
(d) Find the maximum value for Q12. (0≦θ12≦2π) (5%)
6.
https://i.imgur.com/xJ2y0U2.jpg
Neglect the line resistance and capacitance.
(a) Assume that X_D/R_D = 0.4. Find |V2| for P_D = 0.3.
(b) Assume that X_D/R_D = 0. Find |V2| for P_D = 0.3.
(c) Explain why the load voltage |V2| in case (a) is lower than that in case
(b).