52209-mt----power System Control And Stability

NR

Code No: 52209/MT

M.Tech. – II Semester Regular Examinations, September, 2008 POWER SYSTEM CONTROL AND STABILITY (Common to Power System Control & Automation/ Electrical Power Systems) Time: 3hours

Max. Marks:60 Answer any FIVE questions All questions carry equal marks ---

1.a) b)

Derive the expression of Power-Angle curve for single machine connected to an infinite bus through a transmission line. A synchronous machine is connected to an infinite bus through a transformer and a double circuit line. The infinite bus voltage is 1.0 p.u. The Direct Axis transient reactance of the machine is 0.2 p.u, the transformer reactance is 0.10 pu, and the reactance if each of the transmission lines is 0.40 pu, all to a base of the machine rating of the synchronous machine. Initially the machine is delivering a power of 0.8 p.u with a terminal voltage of 1.05 pu. The inertia constant H = 5 mj/KVA. All resistances are neglected. Find the swing equation.

2.

For a single machine connected to an infinite bus, obtain the block diagram with voltage regulation and derive the characteristic equation.

3.

Derive the state space model of one machine system connected to an infinite bus for dynamic stability studies? What is the effect of excitation on dynamic stability?

4.

Why is lead compensation necessary for a power system stabilize? Explain how phase lead is provided using a passive circuit?

5.

With block diagram explain the state space model for an excitation system.

6.

Draw the block diagram of a continuously acting regulator and exciter, Type 1 system and explain function of various blocks. What is the state space model for this? Contd…2.,

Code No: 52209/MT

::2::

7.

How is Lyapunov’s method using energy concept is used for stability Analysis? Explain how Lyapunov’s function for single machine connected to an infinite bus is obtained?

8.

What is the difference between rotor angle stability and voltage stability? How are real and reactive powers affect these stabilities? Give the mathematical formulation of voltage stability problem of single machine connected to load through a line. *****