STUPIDSID
Solve any one question fromQ.1(a,b) and Q.2(a,b)
1(a)
Explain low resistance principle of are interruption in case of circuit breaker.
4 M
1(b)
In a 220kv system, the reactance & capacitance upto the location of circuit breaker is 8Ω and 0.025μf respectively. A resistance of 600Ω is connected across the contacts of the circuit breaker.
Determine-
i) Natural frequency of oscillations
ii) Damped frequency of oscillations
iii) Critical value of resistance which will give no transient oscillations.
Determine-
i) Natural frequency of oscillations
ii) Damped frequency of oscillations
iii) Critical value of resistance which will give no transient oscillations.
6 M
2(a)
A Vacuum circuit breaker is rated as 3 phase 1500 Amp, 2000 MVA, 33 kv, 3 seconds. Determine-
i) the breaking current
ii) Making current
iii) Short time current
iv) Rated normal current
i) the breaking current
ii) Making current
iii) Short time current
iv) Rated normal current
4 M
2(b)
In case of circuit breaker, explain following ratings.
i) Making current
ii) Breaking current
iii) Short time current rating
i) Making current
ii) Breaking current
iii) Short time current rating
6 M
Solve any one question fromQ.3(a,b) and Q.4(a,b)
3(a)
Write a short note on 'zones of protection'
4 M
3(b)
Explain important properties of SF6 gas used in case of SF6 CB
6 M
4(a)
Classify relays on the basis of operating time.
4 M
4(b)
Explain following essential qualities of protective relaying-
i) Stability
ii)Adequatness
iii) Discrimination
i) Stability
ii)Adequatness
iii) Discrimination
6 M
Solve any one question fromQ.5(a,b) and Q.6(a,b)
5(a)
Draw a block diagram of static relay & explain its working. State advantages & limitations of static relay.
10 M
5(b)
Explain the construction & working of metal oxide arresters state its advantages & disadvantages.
8 M
6(a)
Draw a block diagram of numerical relay. & explain its working state its advantages over conventional & static relays.
10 M
6(b)
Write a short note on -
i) Smpling theorem
ii) PMU ( phasor measurement unit)
i) Smpling theorem
ii) PMU ( phasor measurement unit)
8 M
Solve any one question fromQ.7(a,b) and Q.8(a,b)
7(a)
Explain with neat diagram protection scheme of transformer against incipient faults.
8 M
7(b)
With neat diagram explain working of single phasing preventer in case of 3phase induction motor.
8 M
8(a)
Explain the protection of alternater against
i) Loss of prime-mover
ii) Interturn faults
iii) Loss excitation
i) Loss of prime-mover
ii) Interturn faults
iii) Loss excitation
10 M
8(b)
A 3phase 66kv/11kv, star-delta connected transformer is protected by merz price-system. The CTs on LT side have ration of 420/5. Calculate the CT ratio on HT side draw this protection scheme also.
6 M
Solve any one question fromQ.9(a,b) and Q.10(a,b)
9(a)
Explain the effect of arc resistance and power swing on the performance of distance relay.
8 M
9(b)
With a neat sketch, explain three step distance protection scheme for transmission lines.
8 M
10(a)
Explain how impedance relay is used for transmission line protection. Derive its torque equation. Draw its characteristics on R-x plain.
8 M
10(b)
Draw & explain block schematic of carrier aided protection.
8 M
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