1. An industrial consumer hall a daily load pattern of 2000 KW, 0.8 lag for 12 Hra and 1000 kW UPF for 1J Hr. The load factor i= _____.
(a) 0.5
(b) 0.75
(c) 0.6
(d) 2.0
Ans: c
2. What is the maximum value of a load which consume 500 KWh per day at a load factor of 0.40, if the consumer increases the load factor of 0.50 without increasing the maximum demand?
(a) 52.08 kW
(b) 50.8 kW
(c) 4.5 kW
(d) 60 kW
Ans: a
3. A consumer consume. 600 kWh per day at a load factor of 0.40. If the coneumer increases the load factor of 0.70 without increasing the maximum demand, what is the consumption of energy in kWh
(a) 950 kWh
(b) 1000 kWh
(c) 1050 kWh
(d) 1100 kWh
Ans: c
4. The yearly load duration curve of a power plant is a straight line. The maximum load is 750 MW and the minimum load is 600 Mw. The capacity of the plant is 900 MW. What is the capacity factor and utilization factor?
(a) 0.56,0.80
(b) 0.83,0.75
(c) 0.78, 0.9
(d) 0.75, 0.83
Ans: d
5. What is the utilization factor of a power station which supplies the following loads?
Load A: Motor load of200 kW between 10 AM to7PM
Load B : Lighting load of 100 kW between 7 PM to 11 PM
Load C : Pumping load of 110 kW between 3 PM to 10 AM
(a) 1.60
(c) 1.00
(b) 1.32
(d) 2.56
Ans: b
6. A power station supplies the peak load of 60 Mw, 40 MW and 70 MW to three localities. The annual load factor is 0.50 p.u. and the diversity factor of the load at the station is 1.55. The maximum demand on the station and average load respectively will be
(a) 120 MW, 60.8
(b) 90 MW, 50.6
(c) 103.2 MW, 51.61
(d) 100 MW, 0.51
Ans: c
7. The load duration curve for a system, is shown in the figure below. The load factor will be
(a) 0.83
(b) 0.96
(c) 0.67
(d) 0.50
Ans: a
8. A generating station has a maximum demand of 50 Mw, a load factor of 60%, a plant capacity factor of 45% and if the plant while running as per schedule, were fully loaded. The daily energy produced will be
(a) 400 MW
(b) 720 MW
(c) 500 MW
(d) 600 MW
Ans: b
9. A generating station has a maximum, demand of 20 mW, load factor of 60%, a plant capacity factor of 50% and a plant Use factor of 72%. What is the reserve capacity of the plant, if the plant, while running as per schedule, were fully loaded?
(a) 10 MW
(b) 15 MW
(c) 2 MW
(d) 5 MW
Ans: d
10. In the above question, the maximum energy that could be produced daily is
(a) 500 MWhlday
(b) 360 MWhIday
(c) 600 MWhlday
(d) 720 MWhlday
Ans: a
11. In a DC transmission line
(a) it is necessary for the sending end and receiving end to be operated in synchronism.
(b) the effects of inductive and capacitive reactances are greater than in an AC transmission line of the same rating.
(c) there are no effects due to inductive and capacitive reactances.
(d) power transfer capability is limited by stability considerations.
Ans: c
12. The impedance of a circuit is given by z=3+j4. Its conductance will be
(a) 1/3
(b) 3/5
(c) 3/25
(d) 4/5
Ans: c
13. A 100 km transmiesion line ia deaigned for a nominal voltage of 132 kV and conaiala of one conductor per phase. The line reactance is 0.726 ohm/km. The static transmission capacity of the line, in Megawatts, would be
(a) 132
(b) 240
(c) 416
(d) 720
Ans: c
14. The per unit impedance ofa circuit element is 0.15. If the base kV and base MVA are halved, then the new value of the per unit impedance of the circuit element will be
(a) 0.075
(b) 0.15
(c) 0.30
(d) 0.600
Ans: c
15. The conductor of a 10 km long, single phase, two wire line are separated by a distance of 1.5 m. The diameter of each conductor is 1 cm, If the conductors are of copper, the inductance of the circuit is
(a) 50.0 mH
(b) 45.3 mH
(c) 23.8 mH
(d) 19.6 mH
Ans: c
16. For a single phase overhead line having solid copper conductors of diameter 1 cm, spaced 60 cm between centers, the inductance in mH/km is
(a) 0.05 + 0.2 ln 60
(b) 0.2 ln 60
(c) 0.05 + 0.2 ln (6010.5)
(d) 0.2 ln (60/0.5)
Ans: c
17. A 100 km long transmission line is loaded at 110 kV.if the loss of line is 5 MW and the load is 150 MVA, the resistance of the line is
(a) 8.06 ohms per phase
(b) 0.806 ohms per phase
(c) 0.0806 ohms per phase
(d) 80.6 ohms per phase
Ans: a
18. A 3-phase, 11 kv, 50 Hz, 200 kW load has a power factor of 0.8 lag. A delta connected 3-phase capacitor is used to improve the power factor to unity. The capacitance perphase of the capacitor in micro-farads is
(a) 3.948
(b) 1.316
(c) 0.439
(d) 11.844
Ans: b
19. For equilateral spacing of conductors of an untrasposed 3-phase line, we have
(a) balanced receiving end voltage and no communication interference
(b) unbalanced receiving end voltage and no communication interference
(c) balanced receiving end voltage and communication interference
(d) unbalanced receiving end voltage and communication interference.
Ans: c
20. For a 500 Hz frequency excitation, a 50 #em long power line will be modelled as
(a) short line
(b) medium line
(c) long line
(d) data insufficient for decision
Ans: c
21. Which one of the following statement. is not correct for the use of bundled conductors in transmission lines?
(a) Control of voltage gradient
(b) Reduction in corona 1088
(c) Reduction in radio interference
(d) Increase in interference with communication lines
Ans: d
22. The main consideration for higher and higher operating voltage of transmission is to
(a) increase the efficiency of transmission
(b) reduce power losses
(c) increase power transmission capability
(d) both (a) and (b) above
Ans: c
23. A single phaae transmisson line of impedance j 0.8 ohm supplies a resistive load of 500 A at 300 V. The sending end power factor is
(a) unity
(b) 0.8 lagging
(c) 0.8 leading
(d) 0.6 lagging
Ans: d
24. A medium line with parameters A, B, C, D is extended by connecting a short line of impedance Z in series The overall ABCD parameteres of the series combinatton will be
(a) A, AZ, C + D/Z, D
(b) A, AZ + B, C, CZ + D
(c) A + BZ, B, C + DZ, D
(d) AZ, B, C/Z, D
Ans: b
25. When bundle conductors are used in place of single conductors, the effective inductance and capacitance will respectively
(a) increase and decrease
(b) decrease and increase
(c) decrease and remain unaffected
(d) remain unaffected and increase
Ans: c