课程名称︰电力工程导论 课程性质︰电机系选修 课程教师︰许源裕 开课学院：电机资讯学院 开课系所︰电机工程学系 考试日期（年月日）︰2017/11/06 考试时限（分钟）：120(?) 试题 : 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). --

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