**PART A**

1. What is the objective of power system control?

2. What is the objective of power system operation and control?

3. What is load curve?

4. What is daily, Weekly, Annual load curve?

5. What is load duration curve?

6. Define load factor.

7. Define diversity factor.

8. Define spinning reserve.

9. Define Cold reserve.

10. Define hot reserve.

11. Define Maximum Demand.

12. Define demand factor.

13. What is plant use factor?

**PART B**

1. A generating station has the following daily load cycle:

Time (hours) | 0-6 | 6-10 | 10-12 | 12-16 | 16-20 | 20-24 |

Load(MW) | 20 | 25 | 30 | 25 | 35 | 20 |

Draw the Load curve (1)and load duration curve(1) and find

i. Maximum demand(2)

ii. Units generated per day(2)

iii. Average Load(2)

iv. Load Factor.(2)

2. Consider an inductive Load of type Z=R+jX

i. By how many percent will the real load drop if the voltage is reduced by 5 percent?(8)

ii. How would a 2 percent drop in frequency affects the real load, if the load is assumed to have a power factor of 0.8.(8)

3. A Power station has to meet the following demand.

Group A: 200kW between 8 A.M and 6 P.M

Group B: 100kW between 6 A.M and 10 A.M

Group C: 50kW between 6 A.M and 10 A.M

Group D: 100kW between 10 A.M and 6 P.M and 6 P.M and 6 A.M

Plot the daily load cure and load duration curve and determine

(i) Diversity factor

(ii) Units generated per day

(iii) Load factor.

**UNIT II-REAL POWER - FREQUENCY CONTROL**

**PART A**

1. What is the necessity for frequency constancy in a power system? (M/J 2006)

2. What is the need for frequency regulation? (M/J 2006)

3. What is the need for voltage regulation in power system? (M/J 2006)

4. What happens to frequency if the load on the generator increases? (M/J 2006)

5. What is meant by AFRC? (M/J 2006)

6. State the difference between P-f and Q-lVl.(N/D 2006)

7. Define area control error.(M/J 2006)

8. Give the two control loops of large generators. (A/M 2005)

9. What is the basic role of ALFC?(N/D 2004)(N/D 2006)

10. What is meant by control area? (N/D 2004)(N/D 2005)

11. Specify the disadvantage of ALFC loop.(A/M 2005)

12. Write the tie line power deviation equation in terms of frequency?(N/D 2005)

13. List the advantage of multi area operation. (M/J 2007)

**PART B**

1. Using a simplified functional diagram explain the operating features of a speed governing

system.(8) (M/J 2006)

2. Develop a linear mathematical model of a speed governing system.(8) (M/J 2006)

3. Explain the static and dynamic response of ALFC control loop.(8)(N/D 2004)

4. Explain the technique involved in load frequency control (LFC)of a single area

system.(8) (M/J 2006)

5. Explain the principle, involved in tie line frequency control in case of two area system.

(M/J 2006)

6. Develop a linear mathematical model of two area system.(8)(N/D 2004)

7. Explain the tie line bias control of two area system .(8)(N/D 2004)

8. Briefly discuss the LFC control of single area systems.(16)(N/D 2005)

9. Explain the dynamic response of two area system.(8) (N/D 2005)

10. Develop a linear mathematical model of two area system.(6)

11. Explain the tie line bias control of two area system.(6)

12. Describe the expression for Critical gain (4)

13. A single area controlled system has the following data(8)

Area capacity =2000MW

Operating Load=1000MW

R=2.4Hz/p.u.MW

Find K_{I} and find the nature of roots for K_{I}=1.

14. Determine the primary ALFC loop parameter for a control area having the following

data :

Total rated area capacity, P_{r} =2000MW

Normal Operating Load, P_{d}=1000MW

Inertia constant, H= 5 sec

R=2.4Hz/p.u. MW (all area generators)

We shall assume that the load frequency dependency as linear meaning that the old load would increase 1% for 1% frequency increases.

15. A single area controlled system has the following data(8)

Area capacity =3000MW

Operating Load=1500MW

R=3%

H=5 sec and frequency=50 Hz

Compute steady state drop in frequency in Hz for a step load changing of 25MW

16. Two 50 Hz power station are connected by means of an interconnected cable of negligible

impedance so that the station are in parallel. Station A has a full load capacity of 15 MW and uniform speed regulation of 3%, Station B has a capacity of 4MW and a uniform speed regulation of 4%. The load on the bus bar of station A is 10MW and B is 4MW. Calculate the generated output of each station. The power transmitted by the interconnected and the operating frequency .Assume frequency governor action and the speed changer of generator were set to have a frequency of 50 Hz

only for 2 units given

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