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WorksheetsEE8702 POWER SYSTEM OPERATION AND CONTROL /MODEL NOV 2020
Total questions: 45
Worksheet time: 28mins
1.1 Objectives of power system is/are
a. Cost of electrical energy per KWh is to be minimum
b. Rated voltage and frequency has to be supplied to the consumers
c. both a and b
d .neither a nor b
1.2 The frequency of the power system control the
a. Active power
b. Reactive power
c. (a) and (b) both
d. None of them
1. 3 The value of diversity factor is ............. than 1
a. equal to
b. lesser
c. more
d. greater
1. 4 Area under the daily load curve divided by 24 gives..............
a. average load
b. maximum demand
c. units generated
d. load factor
1.5 What is a load factor?
a. The ratio of average to maximum demand.
b. The ratio of maximum demand to average load.
c. The product of maximum demand and average load.
d. The ratio of average load to the plant capacity.
1.6 The heart of the speed governor system, which controls the change in speed, is
a. Linkage mechanism.
b. Fly-ball speed governor.
c. Speed changer.
d. Hydraulic amplifier.
1.7 (2 marks)
When two identical AC-generating units are operated in parallel on governor control, and one machine has a 5% governor droop and the other a 10% droop, the machine with the greater governor droop will
a. Tend to take the greater portion of the load changes.
b. Share the load equally with the other machine.
c. Tend to take the lesser portion of the load changes.
d. None.
1.8 ( 2 marks) A thermal generating station has a installed capacity of 15 MW and supplies a daily load of 10 MW for 12 hours and 5 MW for remaining 12 hours. The plant capacity factor for this station is
a. 1
b. 0.75
c. 0.67
d. 0.5
1.9 ( 2 marks) More efficient plants are used as
a. Base load plant
b. Peak load plant
c. Both 1 and 2
d. Non of the above
2.1 main control loops in generating stations are:
a. ALFC.
b. AVR.
c. Both (a) and (b).
d. None of these.
2.2 In an ALFC loop, Δfcan be reduced using ________ controller.
a. Differential.
b. Integral.
c. Proportional.
d. All of these.
2.3 Unit of Regulation(R) is ________.
a. Hz/MVAr.
b. Hz/MVA.
c. Hz/MW.
d. Hz-s.
2.4 Unit of H of a synchronous machine is:
a. MJ/MW.
b. MJ/MVA.
.
c. MJ/s.
d. MW-s
2.5 A signal area system is one in which:
a. It is not connected to any other system.
b. Total demand on the system should be fully met by its own local Generation.
c. All generators swing together.
d. All of these.
2.6 In a signal area system, all generators working remain in synchronism maintaining their relative power angles; such a group of generators is called ________.
a. Swing group.
b. Synchronous group.
c. Coherent group.
d. None of these
2.7 (2 marks)
The surplus power (ΔPg– ΔPd) can be absorbed by a system:
a. By increasing the stored K Є of the system at the rate d/dt(wKE)
b. By motor loads
.
c. There is no absorption of surplus power by the system.
d. Both (a) and (b).
2.8 (2 marks) For a two-area system, Δ f is related to increased step load M1 and M 2 with area frequency response characteristics β1 and β2 is:
a. M1+ M2/β1+ β2.
b. (M1+ M2) (β1+ β2).
c. - (M1+ M2)/ (β1+ β2).
d. None of these.
2.9 ( 2 marks) ACE equation for a general power system with tie-line bias control is:
a. ΔPij+ BiΔfi.
b. ΔPij–BiΔfi.
c. ΔPij/BiΔfi.
d. None of these.
3.1 The voltage at the bus can be controlled by the injection of _____ power of the correct sign.
a. Real.
b. Reactive.
c. Complex.
d. Both real and reactive.
3.2 . Permissible voltage variation is _____.
a. ± 10%.
b. ± 15%.
c. ± 20%.
d. ± 5%.
3.3 The function of a pilot exciter is:
a. To supply current to the rotor circuit.
b. To maintain constant voltage excitation for the main exciter.
c. To supply variable excitation for the main exciter.
d. None of these.
3.4 . The function of an amplidyne is:
a. To provide the constant excitation to a synchronous generator.
b. To provide large currents to the field winding of a main exciter.
c. To provide supply to the synchronous machine.
d. None of these.
3.5 The disadvantage of a series capacitor is that it produces _____voltage across the capacitor under short-circuit condition.
a. Low.
b. High.
c. Very low.
d. Either (a) or (b).
3.6 (2 marks) . When the excitation increases, the current ___________ and the power angle ___________.
a. Increases, increases.
b. Decreases, increases.
c. Increases, decreases.
d. Decreases, decreases
3.7 ( 2 marks) Disadvantages of shunt capacitors are _____.
a. Fall of voltage.
b. Reduction in VArs.
c. Reduction in effectiveness.
d. All of these
3.8 (2 marks )Voltage regulation is define as
a.The per unit change in the sending end voltage magnitude for a specific variation in the receiving end voltage from no load to full load
b.The per unit change in the receiving end voltage magnitude for a specific variation in the sending end voltage from no load to full load
c. The per unit change in the sending end voltage magnitude for a specific variation in the receiving end voltage
d. None of above
4.1 . This curve is showing?
a. Increment Fuel Cost Curve
b. Input Output Curve
c. Operating cost curve
d. None of these
4.2 The economic dispatch problem is use to calculate
a. Minimise the total cost of generating real power
b. Minimise the total cost of generating reactive power
c.Both A and B
d.None of them
4.3 . For economic measure the generators at a power plant operate at _____________.
a. Equal incremental cost
b. Equal loads
c. Equal power rating
d. All of these
4.4 In economic dispatch fuel cost efficient bi relates
a, investment cost
b,operating cost
c. salaries
d. none
4.5 The need for unit commitment are
a. To reduce loss
b. To reduce fuel cost
c. enough units will be committed to supply the system load
d. All of the above
4.6 Full load average production cost is
a. (Net heat rate at full load )+ fuel cost
b. (Net heat rate at full load) * fuel cost
c. (Net heat rate at full load )- fuel cost
d. (Net heat rate at full load) /fuel cost
4.7 (2 marks)
a.24
b. 20
c. 22
d. 23.5
4.8 (2 marks)
a. P1= 142.5 MW & P2 =107.5 MW
a. P1= 112.5 MW & P2 = 125 MW
a. P1= 100 MW & P2 =145 MW
a. P1= 125.8 MW & P2 = 85.96 MW
4.9 (2 marks) Which of the following plant is expected to have the longest expected life ?
a. Hydroelectric
b. steam
c. Diesel
d. All have equal life.
5.1 National
Load Dispatch Center is run by
a. Power Grid Corporation of India Limited (PGCIL)
b. Power System Operation Corporation Limited (POSOCO)
c. Government of India
d. Government of Delhi
5.2 How many regional load dispatch centres are available in India?
a. 4
b. 5
c. 8
d 6
5.3 SCADA system encompass the transfer of data between a central host computer and a number of___________ and /or programmable logic controllers (PLCs), and the central host and the operator terminals
a. Remote terminal units (RTUs)
b, Master Terminal Units (MTUs)
c. Junction Box
d. Micro-controller
5.4 A central host computer server or servers called ________
a.Switch
b.Master Terminal Units (MTUs)
c. Junction Box
d. Micro controller
5.5 Contingency analysis are used to study
a. Load flow study
b.State Estimation
c. Economical operation
d. Outage events
5.6 secure state is the one in which the following occurs
a, contingency happens
b. overloading of generators
c. spinning reserve margin reduces
d.over loading of transformers
5.7 Brown out and Block out in power system operation defined as
a. voltage increasing by the service provider / full power every where in grid
b. voltage decreasing by the service provider / full power every where in grid
c. voltage decreasing by the service provider / no power in the grid
d.all the above
5.8 (2 marks ) Which
estimation method is best suitable for state estimation in a power system?
a. Least square estimation
b.Equal Weighted Least square estimation
c. maximum likelihood Weighted least square estimation
d. Fast decoupled
5.9 (2 marks ) Power system having N number of buses, the state variable ‘x’ may be defined as_______number of buses voltage angle and __________number of bus voltage
magnitude
a.N-2,N-1
b . N-1,N
c. N,N
d, N,N-1
5.10 Automatic generation control is the one in which the following combination are in included in ENERGY CONTROL CENTRE (ECC)
a. exciter and generator
b, primary and secondary ALFC
c. AVR and ALFC
d . ALL THE ABOVE
