Download PTU B-Tech EEE 2020 Dec 6th Sem 71148 Power System Ii (Switch Gear And Protection) Question Paper

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Roll No. Total No. of Pages : 02

Total No. of Questions : 18

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B.Tech. (EE) (Electrical & Electronics Engg.) (2012 Onwards)/
B.Tech. (Electrical Engineering & Industrial Control)(2012 to 2017)
(Sem.-6)

POWER SYSTEM-II
(Switch Gear & Protection)

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Subject Code : BTEE-602
M.Code : 71148

Time : 3 Hrs. Max. Marks : 60

INSTRUCTIONS TO CANDIDATES :

1. SECTION-A is COMPULSORY consisting of TEN questions carrying TWO marks each.

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2. SECTION-B contains FIVE questions carrying FIVE marks each and students have to attempt any FOUR questions.
3. SECTION-C contains THREE questions carrying TEN marks each and students have to attempt any TWO questions.

SECTION-A

Answer briefly :

1. What are the different types of faults in power system transmission line?

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2. What type of relay is best suited for generator protection?
3. What is the role of metal oxide arresters in overvoltage protection?
4. Give the types of circuit-breakers.
5. Write any two advantages of SF₆ circuit breakers.
6. What is breaking capacity of circuit breaker?

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7. List out the application of static relay.
8. What is differential protection?
9. What is the effect of power system faults?
10. Differentiate between a fuse and a protective relay.

SECTION-B

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1. Briefly describe the different types of testing schemes of circuit breakers.
2. Discuss the role of protective relays in a modern power system.
3. Explain current chopping phenomenon.
4. Explain the construction and operating principle of over current relay with directional scheme.
5. A three phase power transformer has a voltage ratio of 33/6.6 kV and is star delta connected. The protective CTs on the 6.6 kV side have a current ratio of 100:1. What must be the ratio of protective CTs on the 33 kV side.

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SECTION-C

1. Discuss recovery rate theory and energy balance theory of arc interruption in a circuit breaker.
2. Explain the principle of a distance relay, stating clearly the difference between electromagnetic version of an impedance relay and aimho relay.
3. In a 132kV systems, the reactance and capacitance up to the location of the circuit breaker is 5 Ohm and 0.02uF respectively. A resistance of 500 Ohm is connected across the contacts of the circuit breaker. Determine :
   a) Natural frequency of oscillations:
   

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   b) Frequency of damped oscillations.
   c) Critical value of resistance.
   d) The value of resistance which will give frequency of damped oscillations which is equal to 1/4th the natural frequency.

NOTE : Disclosure of identity by writing mobile number or making passing request on any page of Answer sheet will lead to UMC against the Student.

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