# In a Kelvin's Double Bridge, two sets of readings are taken when measuring a low resistance, one with the current in one direction and the other with direction of current reversed. This is done to eliminate the effect of

1.  contact-resistance

3.  changes in battery voltage

4.  thermo-electric emfs

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thermo-electric emfs

Explanation :
No Explanation available for this question

# A transformer er is rated at 11 kV/0.4 kV, 500 kVa, 5% reactance. What is ,the short. circuit MVA of the transformer when connected to an infinite bus

1.  20 MVA

2.  10 MVA

3.  15 MVA

4.   5 MVA

4

10 MVA

Explanation :
No Explanation available for this question

# When a potentiometer is used for measurement of voltage of an unknown source, the power consume in the circuit of the unknown source under null conditions is

1.  very high

2.  high

3.  small

4.  ideally zero

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ideally zero

Explanation :
No Explanation available for this question

# Standardization of potentiometers is done in order that, they become

1.  accurate

2.  Precise

4.  accurate and precise

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Explanation :
No Explanation available for this question

# Two 11 kV, 20 MVA, three phase, star connected generators operate in parallel. The positive negative and zero sequence reactance of each having j 0.18, j 0.15, j 0.10 p.u. Assume that the grounded generator is solidly grounded. What is the voltage of the healthy phase for a double line to ground fault at terminals of the generator Assume (solid fault Zf= 0)

1.  0.45

2.  0.969

3.  0.251

4.   0.85

4

0.969

Explanation :
No Explanation available for this question

# Two generating stations having short circuit capacities of 1200 MVA and 800 KVA respectively and operating at 11 kV are, linked by an interconnected cable having a reactance of 0.5Ω per phase The short circuit current of each station will be

1.  1600 MVA, 1800 MVA

2.  1200 MVA, 200 MVA

3.  1009 MVA, 1200 MVA

4.  1386 MVA, 1001 MVA

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1386 MVA, 1001 MVA

Explanation :
No Explanation available for this question

# A Buchholz relay is used for

1.  protection of a transformer againts all internal faults

2.  protection of a transformer against external faults

3.  protection of a transformer against both internal and external faluts

4.   protection of induction motors

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protection of a transformer againts all internal faults

Explanation :
No Explanation available for this question

# Resistance switching in normally employed in

1.  all breakers

2.  bulk oil breakers

3.  minimum oil breakers

4.  air blast circuit breakers

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air blast circuit breakers

Explanation :
No Explanation available for this question

# If the fault current is 2000 A, the relay setting is 50 % and CT ratio is 400: 5, then plug setting multiplier will be

1.  25A

2.  15A

3.  50A

4.  10A

4

10A

Explanation :
No Explanation available for this question

# Reactance relay is normally preferred for protection against

1.  earth faults

2.  phase faults

3.  open corciut faults

4.  none of these

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