71. A system is said to be effectively grounded if its
A. neutral is grounded directly.
B. ratio of ? > 3.0 XiX0
C. ratio of ? >2.0 Xi X0
D. ratio of ?2- <3.0 Xi
72. Self GMD method is used to evaluate
C. inductance and capacitance both
D. none of these
73. Stringing chart is useful for
A. finding the sag in the conductor.
B. in the design of tower
C. in the design of insulator string
D. finding the distance between the tower.
74. Leakage resistance of a 50 km long cable is 1 Ma. For a 100 km long cable it will be
C. 0.66 MSZ
D. none Of these
75. Three insulating materials with breakdown strengths of 250 kV/cm, 200 kV/cm, 150 kV/cm and permittivities of 2.5, 3.0 and 3.5 are used in a single core cable. If the factor of safety for the materials is 5, the location of the materials with respect to the core of the cable with be
A. 2.5, 3.0, 3.5
B. 3.0, 2.5, 3.5
C. 3.5, 3.0 2.5
D. 3.5, 2.5, 3.0
76. Mho relay is normally used for the protection of
A. long transmission lines.
B. medium length lines
C. short length lines
D. no length criterion
77. A Mho relay is a
A. voltage restrained directional relay.
B. voltage controlled over current relay.
C. directional restrained over current relay.
D. directional restrained over voltage relay.
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