AP ECET EEE 2016-3

1.A mho relay is normally used for protection of

A. Short length lines
B. Long length lines
C. Medium length lines
D. No length criterion.

Answer : Long length lines
Explain:-

2.A circuit breaker normally operates

A. When the power is to be supplied
B. When the line is to be tested
C. When the switch is to be put on
D. When ever fault occurs in line.

Answer : When ever fault occurs in line
Explain:-

3.A transmission line is protected by.

A. Inrush protection
B. Feeder protection
C. Time graded and current graded over current protection
D. Buchholz's relay protection.

Answer : Time graded and current graded over current protection
Explain:-

4. Bus bar protection is achieved by using relay.

A. Over current
B. Differential
C. Distance
D. None.

Answer : Differential
Explain:-

5. The fact that a conductor carries more current on the surface as compared to core is known as

A. Skin effect
B. Corona
C. Permeability
D. Proximity effect

Answer : Skin effect
Explain:-

6.In overhead transmission lines the effect of capacitance can be neglected when the length of time is less than

A. 200 km
B. 100 km
C. 160 km
D. 80 km

Answer : 80 km
Explain:-

7.A 4 insulator string has string efficiency of 80%, 45 k V is applied to the string What is voltage across lowest unit?

A. 11.3 KV
B. 16 KV
C. 14.06 KV
D. 17.02 KV.

Answer : 14.06 KV
Explain:-

8. Electric stress is expressed in terms of

A. ohms/cm
B. kV/cm
C. farad/cm
D. none.

Answer : kV/cm
Explain:-

9. A back to back HVDC link can be advantageous compared to AC primarily because

A. It is cheaper
B. of stabilityconsiderations
C. of controlled powerflow
D. Low voltage.

Answer : of controlled powerflow
Explain:-

10. The capacitance and Inductance per unit length of a 3-phase line, operating at 110 kV\nare 0.01 microfarad and 2.5 mH. The surge Impedance of the line is

A. 50 ohms
B. 500 ohms
C. 250 ohms
D. 25 ohms.

Answer : 500 ohms
Explain:-