SREC EEE
PSOC A.U QP (Nov 2011 – May 2015) – Unit - II
DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING
Year/Sem : IV/VII
POWER SYSTEM OPERATION AND CONTROL [EE 2401]
UNIT – II A.U QUESTIONS (Nov 2011 – May 2015)
Part – A
1. What is “ AGC ” ? (Nov 2011)
2. What are the conditions necessary for sharing load operating in parallel between the two
synchronous machines ? (Nov 2011)
3. What are the classification of system load ? (May 2012)
4. What is meant by “ Load frequency control ” ? (May 2012)
5. What are the types of automatic load frequency control for interconnected power system?
(Nov 2012)
6. What is automatic load dispatching? (Nov 2012)
7. What is the function of load frequency control on a power system? (May 2013) (Nov 2013)
8. Define speed droop. (May 2013)
9. Give two conditions for proper synchronizing of alternators. (Nov 2013)
10. State any two necessities to put alternators in parallel.
(May 2014)
11. What are the assumption made in dynamic response of uncontrolled case? (May 2014)
12. What is meant by control area?
(Nov 2014)
13. State the control objective of two area load frequency control. (Nov 2014)
14. Find the open loop gain of an Automatic voltage regulator loop if the static error does not
exceed 2 %. (May 2015)
15. Brief the application of secondary ALFC loop in power system networks. (May 2015)
Part – B
1. Draw the block diagram of uncontrolled two area load frequency control system and
explain the salient features under static conditions.
(16) (Nov 2011) (May 2013)
2. How is speed governor mechanism modeled? Explain its operations with the speed load
characteristics.
(16) (Nov 2011)
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SREC EEE
PSOC A.U QP (Nov 2011 – May 2015) – Unit - II
3. What are the components of speed governor system of an alternator? Derive the
mathematical model of speed governor system with aid of block diagram. (16) (May 2012)
(Nov 2013)
4. With the block diagram of speed governing system, explain the Automatic Load
frequency control. Also derive necessary equations.
(16) (May 2015)
5. Explain the dynamic response of single area load frequency control. Also discuss the
effect of P-I controller on single area load frequency control.
(16) (May 2012)
6. With a neat block diagram, explain the single area load frequency control system.
(16) (Nov 2012)(Nov 2014)
7. Discuss the integration of economic dispatch control with automatic generation control.
(08) (Nov 2012)
8. Derive an expression for load sharing between two alternators. What are the effects of
fuel supply and change of excitation?
(08) (Nov 2012)
9. Develop a schematic of speed governing system and explain its operation.(08) (May 2013)
10. Develop the state variable model of a two area system and state the advantages of the
model.
(16) (May 2014)
11. Two generators rated 200 MW and 400 MW are operating in parallel. The droop
characteristics of their governors are 4 % and 5 % respectively from no load to full load.
Assume that the generators are operating at 50 Hz at no load, how would a load of 600
MW be shared between them? What will be the system frequency at this load? Assume
free governor operation. Also find the load sharing if both governors have a
droop of 4 %.
(08) (May 2013) (Nov 2013) (Nov 2014)
12. An isolated power system has the following parameters:
Turbine rated output = 300 MW, Nominal frequency = 50 Hz,
Governor speed regulation = 0.05 p.u, Inertia constant = 5,
Turbine time constant = 0.5 sec. Governor time constant = 0.2 sec,
Load change 60 MW. The load varies by 0.8 % for a 1 % change in frequency.
Determine the steady state frequency deviation in Hz.
(16) (May 2014)
13. A sub-grid has total rated capacity 2500 MW. It encounters a load increase of 50 MW if
the normal operating load is 1000 MW. Assume inertia constant(H) to be 5 sec and
regulation of the generators in the system as 2 Hz/p.u MW. Find (i) ALFC loop
parameters, (ii) Static frequency drop, (iii) Transient response of the ALFC loop. Assume
load frequency dependency to be linear.
(16) (May 2015)
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