VARDHAMAN COLLEGE OF ENGINEERING
(AUTONOMOUS)
B. Tech VI Semester Regular Examinations, May 2018
(Regulations: VCE-R15)
POWER SYSTEM DYNAMICS AND STABILITY
(Electrical and Electronics Engineering)
Date: 28 May, 2018 FN
Time: 3 hours
Max Marks: 75
Answer ONE question from each Unit
All Questions Carry Equal Marks
Unit I
1.

Explain the Normal secure state, alert state of operation of power system.
6M

A generator is supplying power to a load centre through a transmission line. The power output of the generator is increased slowly while maintaining the magnitudes of the voltages V1 and V2 constant at 1.0 pu. By manual control (of both generator excitation and infinite bus voltage). Find the steady state stability limit of power that can be transmitted. Assume xt 0.14, xline 0.6, Zt j0.12, xg 0.4.
Fig.1
9M
2.

Discuss recent trends in power system dynamic and stability problems.
5M

A generator is connected to an infinite bus through an external impedance of jxe. The generator is represented by a voltage source in series with a reactance of xg. If Eg=Eb (infinite bus voltage)=1.0, xg=0.3 (all in p.u) for pb=1.0p.u., find the equilibrium values of in the range of Test their stability (Pb is the received power at the infinite bus). Assume infinite bus angle as zero.
10M
Unit II
3.

What are the torque equations during the modeling of a synchronous machine?
6M

How are the transient and subtransient quantities from the equivalent circuit parameters?
9M
4.

Obtain the torque equations after Park's transformation.
8M

How are the rotor base quantities chosen for a synchronous machine?
7M
Unit III
5.

Discuss different types of excitation systems based on the power source for exciter. Also draw the functional block diagram of excitation control system.
7M

Discuss static load representation.
8M
6.

Draw the functional block diagram of mechanical hydraulic speed governing system for steam turbines and explain.
7M

With a single phase equivalent of a transmission line, explain modeling of a transmission network.
8M
Unit IV
7.

Discuss stator equations for synchronous machine model.
8M

Write a note on system simulations.
7M
8.

What are the rotor mechanical equations of model 1.1 of synchronous generator?
7M

What are the rotor equations of model 2.2 of synchronous generator?
8M
Unit V
9.

Explain how the "transient voltage instability" affects voltage instability and collapse.
7M

Write briefly about integrated analysis of voltage and angle stability.
8M
10.

Discuss with relevant equation, synchronizing torque and damping torques when applied to fast excitation system.
7M

Discuss the dynamics of load restoration.
8M