Power Plant Engineering Objective Questions

61. Connected load means

(a) installed electrical load in the premises of a consumer.
(b) maximum load a consumer draws.
(c) load drawn by consumer at any instant.
(d) none of the above.

62. The maximum demand of a power station is

(a) sum of the maximum demands of all its consumers.
(b) greatest average load in a specified time.
(c) peak value of load in a specified time.
(d) all of the above.

63. Demand factor is defined as the ratio of

(a) average load to maximum demand.
(b) maximum demand to connected load.
(c) connected load to maximum demand.
(d) maximum demand to average load.

64. Demand factor on a power system is

(a) always greater than unity.
(b) normally greater than unity.
(c) always lesser than unity.
(d) normally lesser than unity.

65. The load factor is equal to

(a) average load/peak load.
(b) peak load/average load.
(c) average load/connected load.
(d) average load/base load.

66. A power station’s plant load factor is defined as the ratio of

(a) the energy generated to that of maximum energy that could have been generated.
(b) average load to peak load.
(c) minimum load to peak load.
(d) minimum load to average load.

67. Load factor of a power plant is

(a) generally equal to unity.
(b) always less than unity.
(c) always more than unity.
(d) normally more than unity.

68. The load factor for domestic loads may be taken as

(a) about 85%
(b) 50 – 60%
(c) 25 – 50%
(d) 10 – 15%

69. Load factor for heavy industries may be taken as

(a) 70 – 80%
(b) 40 – 50%
(c) 25 – 40%
(d) 20 – 25%

70. The annual load duration curve of a power supply system may be considered as a straight line from 40 MW to 8 MW. The load factor of the system is

(a) 20%
(b) 40%
(c) 60%
(d) 83.33%
(e) none of the above.

71. An industrial consumer has a load pattern of 2,000 kW 0.8 lag for 12 hours and 1,000 kW unity power factor for 12 hours. The load factor is

(a) 0.5
(b) 0.75
(c) 0.6
(d) 2.0

72. The maximum demand of a consumer is 2 kW and the corresponding daily energy consumption is 30 units. What is the corresponding load factor?

(a) 25%
(b) 50%
(c) 62.5%
(d) 75%

73. Diversity factor is the ratio of

(a) sum of maximum demands of consumers ÷ system maximum demand.
(b) maximum demand of consumers ÷ average demand.
(c) demand of all consumers ÷ average demand.
(d) none of the above.

74. The daily energy produced in thermal power station is 720 MWh at a load factor of 0.6. What is the maximum demand of the station?

(a) 50 MW
(b) 30 MW
(c) 72 MW
(d) 720 MW

75. Diversity factor in a power system is

(a) always less than unity.
(b) normally less than unity.
(c) always more than unity.
(d) normally more than unity

76. Diversity factor x maximum demand is

(a) average demand.
(b) sum of consumer’s maximum demands.
(c) installed capacity.
(d) generated power.

77. Diversity factor has direct effect on

(a) fixed cost per unit generated.
(b) operating cost per unit generated.
(c) both (a) and (b).
(d) neither (a) nor (b).

78. The knowledge of diversity factor helps in computing

(a) plant capacity.
(b) average load.
(c) units (kWh) generated.
(d) peak demand.

79. Plant capacity factor is

(a) actual energy produced ÷ maximum possible energy that could have been produced (based on installed capacity).
(b) actual energy produced ÷ plant capacity hours for which the plant has been in operation.
(c) energy generated in a given period ÷ (maximum demand x hours of operation in given period).
(d) none of the above.

80. Utilization factor is defined as the ratio of

(a) average demand to rated capacity of the power plant.
(b) maximum demand on the power plant to the rated capacity of the power plant.
(c) rated capacity of the power plant to the maximum demand.
(d) none of the above.

81. Capacity factor will be very low when the power plant

(a) is operated as base load plant.
(b) is operated for supplying base loads as well as peak loads.
(c) is operated hi emergency only.
(d) is under maintenance.

82. A thermal generating station has an installed capacity of 15 MW and supplies a daily load of 10 MW for 12 hours and 5 MW of remaining 12 hours. The plant capacity factor for this station is

(a) 1
(b) 0.75
(c) 0.67
(d) 0.5

83. A generating station has a maximum demand of 30 MW, a load factor of 60% and a plant capacity factor of 50%. The reserve capacity of the plant is

(a) 5 MW
(b) 4 MW
(c) 6 MW
(d) 10 MW

84. If the rated plant capacity and maximum load of a power station are equal then

(a) load factor is unity.
(b) capacity factor is unity .
(c) utilization factor is unity.
(d) load factor and capacity factor are equal.
(e) both (c) and (d).

85. Spinning reserve is

(a) the reserve generating capacity which is available for service but not in operation.
(b) the reserve generating capacity which is connected to the bus and is ready to take load.
(c) the reserve generating capacity which is in operation but is not in service.
(d) none of the above.

86. The power which must be available ever under emergency conditions is known as

(a) spinning reserve.
(b) cold reserve.
(c) firm reserve.
(d) hot reserve.

87. In a power plant, a reserve generating capacity which is in operation but not in service, in called the

(a) cold reserve.
(b) hot reserve.
(c) spinning reserve.
(d) firm reserve.

88. A power plant has a maximum demand of 15 MW. The load factor is 50% and the plant factor is 40%. The operating reserve is

(a) 3 MW
(b) 3.75 MW
(c) 6 MW
(d) 7.5 MW

89. Which of the following relations holds good ?

(a) Maximum demand = Connected load x demand factor.
(b) Average load = Maximum load x load factor.
(c) Capacity factor = Utilization factor x load factor.
(d) All of the above.

90. Two areas A and B have equal connected loads. However load diversity in area A is more than in area B. Then

(a) maximum demands of the two areas would be equal.
(b) maximum demand of A would be more than that of B.
(c) maximum demand of B would be more than that of A.
(d) maximum demand of A may be more or less than that of B.

91. A large diversity factor of the load in a power system

(a) reduces the installation cost.
(b) increases the installation cost.
(c) does not affect the installation cost

92. As the load factor of a generating plant increases, the generation cost per kWh generated

(a) decreases.
(b) increases.
(c) remains same.
(d) none of these.

93. In order to have a lower cost of electrical energy generation

(a) the load factor and diversity factor should be low.
(b) the load factor should be low but diversity factor should be high.
(c) the load factor should be high but the diversity factor should be low.
(d) the load factor and diversity factor should be high.

94. In a power station, the cost of generation of power reduces most effectively when

(a) diversity factor alone increases.
(b) both diversity factor and load factor increase.
(c) load factor alone increases.
(d) both diversity factor and load factor decrease

95. The economics of power plant is greatly influenced by:

1.load factor 2. utilization factor 3. unit capacity 4. type of load
(a) 1, 2, 3 and 4.
(b) 1, 3 and 4.
(c) 1, 2 and 3.
(d) 2, 3 and 4.

96. Flat rate tariff can be charged on the basis of

(a) connected load.
(b) units consumed.
(c) maximum demand.
(d) both (a) and (b).

98. Domestic consumers are usually charged

(a) flat demand tariff.
(b) block rate tariff.
(c) flat rate tariff.
(d) off peak tariff.

99. If the tariff for electrical energy charges provides incentive by way of reduced charges for higher consumption, then it may be concluded that the

(a) load factor is high.
(b) power factor is high.
(c) plant has sufficient reserve capacity.
(d) power is generated through hydropower plant.

100. Two part tariff is charged on the basis of

(a) connected load.
(b) units consumed.
(c) maximum demand.
(d) both (a) and (b).