ENEE20002 Advanced Electrical

Question: 1

4 A 100-MVA 33-kV 3-phase generator has a sub-transient reactance of 15%. The generator is connected to the motors through a transmission line and transformers. The motors have rated inputs of 30 MVA, 20 MVA, and 50 MVA at 30 kV with 20% sub-transient reactance. The transformers are rated at 110 MVA, 32/110 kV with leakage reactance of 8%. The line has reactance of 50 ohm. Selecting the generator rating as base quantities in the circuit, determine the base quantities for other parts of the system and evaluate the corresponding per unit values.

Question: 2

Determine the feedback transfer function of the system with following transfer function analytically. Evaluate the frequency response of the closed loop system using MATLAB. Motor: 1 ????????(????????+10) ;

Power amplifier: 1 ????????+20; Controller: ???????? = 700

Question: 3

A permanent - magnet DC motor is known to have an armature resistance of 1.03 ?. When operated at no load from a DC source of 70 V, it is observed to operate at a speed of 2100 r/min and to draw a current of 1.25 A. Find the no load rotational losses of the motor and the power output at 1700 r/min from a 48 V source.

Question 4

Given the unity feedback system for DC motor with following transfer function ????????(????????) = ????????(???????? + 4) ????????(???????? + 1.2)(???????? + 2) Find the range of K that keeps the system stable.