Code No: RR320205

RR

SET-1

B. Tech III Year II Semester Examinations, December/January -2011-2012 POWER SYSTEMS - III (ELECTRICAL AND ELECTRONICS ENGINEERING)

Time: 3 hours

Max. Marks: 80 Answer any five questions All questions carry equal marks ---

Derive expression for reflection & refraction coefficients. Write about Bewley’s lattice coefficients.

2.a) b)

Explain about attenuation and distortion of traveling waves. Discuss about effectively grounded system and ungrounded system.

[8+8]

3.a) b)

Discuss any one type of neutral grounding. What are the different types of lighting arrestors? Explain with diagrams.

[8+8]

4.a)

Classify the types of circuit breakers when the arc quenching medium is the criterion. With the help of block diagrams explain the principle of working of i) Minimum oil circuit breaker ii) Air blast circuit breaker. [8+8]

[8+8]

or ld

b)

.in

1.a) b)

Discuss the design features of current limiting reactors. Draw the block diagram of induction cup type relay also explain its working principle. [8+8]

6.

A generator connected through a 3-cycle circuit breaker to a transformer is rated

uW

5.a) b)

nt

10 MVA, 13.8 kv, with reactance of X d′′ =12%, X d′ =16%, and X d = 100% . It is operated at no load and rated voltage when a 3-phase short circuit occurs between the breaker and the transformer. Determine: a) The sustained short circuit current in breaker b) The initial symmetrical rms current in the breaker. c) The maximum possible D.C. component of the short circuit current in the breaker. d) The momentary current rating of the breaker. e) The current to be interrupted by the breaker. f) The interrupting KVA. [16]

Draw the characteristics of IDMT relay and explain the procedure of obtaining these characteristics. Derive characteristic equation of distance relay. Also draw the characteristics curves of Impedance and admittance relays. [8+8]

Aj

7.a)

b)

8.a)

b)

Draw the block diagram of static instantaneous over current relay. Also explain it’s operation. Explain the differential protection of transformer. [8+8]

--ooOoo—

Code No: RR320205

RR

SET-2

B. Tech III Year II Semester Examinations, December/January -2011-2012 POWER SYSTEMS - III (ELECTRICAL AND ELECTRONICS ENGINEERING)

Time: 3 hours

Max. Marks: 80 Answer any five questions All questions carry equal marks ---

Discuss any one type of neutral grounding. What are the different types of lighting arrestors? Explain with diagrams.

2.a)

Classify the types of circuit breakers when the arc quenching medium is the criterion. With the help of block diagrams explain the principle of working of i) Minimum oil circuit breaker ii) Air blast circuit breaker. [8+8]

[8+8]

or ld

b)

.in

1.a) b)

3.a) b)

Discuss the design features of current limiting reactors. Draw the block diagram of induction cup type relay also explain its working principle. [8+8]

4.

A generator connected through a 3-cycle circuit breaker to a transformer is rated

Draw the characteristics of IDMT relay and explain the procedure of obtaining these characteristics. Derive characteristic equation of distance relay. Also draw the characteristics curves of Impedance and admittance relays. [8+8]

nt

b)

uW

5.a)

10 MVA, 13.8 kv, with reactance of X d′′ =12%, X d′ =16%, and X d = 100% . It is operated at no load and rated voltage when a 3-phase short circuit occurs between the breaker and the transformer. Determine: a) The sustained short circuit current in breaker b) The initial symmetrical rms current in the breaker. c) The maximum possible D.C. component of the short circuit current in the breaker. d) The momentary current rating of the breaker. e) The current to be interrupted by the breaker. f) The interrupting KVA. [16]

6.a)

Aj

b)

Draw the block diagram of static instantaneous over current relay. Also explain it’s operation. Explain the differential protection of transformer. [8+8]

7.a) b)

Derive expression for reflection & refraction coefficients. Write about Bewley’s lattice coefficients.

[8+8]

8.a) b)

Explain about attenuation and distortion of traveling waves. Discuss about effectively grounded system and ungrounded system.

[8+8]

--ooOoo--

Code No: RR320205

RR

SET-3

B. Tech III Year II Semester Examinations, December/January -2011-2012 POWER SYSTEMS - III (ELECTRICAL AND ELECTRONICS ENGINEERING)

Time: 3 hours

Max. Marks: 80 Answer any five questions All questions carry equal marks ---

Discuss the design features of current limiting reactors. Draw the block diagram of induction cup type relay also explain its working principle. [8+8]

2.

A generator connected through a 3-cycle circuit breaker to a transformer is rated

b)

4.a) b)

or ld

10 MVA, 13.8 kv, with reactance of X d′′ =12%, X d′ =16%, and X d = 100% . It is operated at no load and rated voltage when a 3-phase short circuit occurs between the breaker and the transformer. Determine: a) The sustained short circuit current in breaker b) The initial symmetrical rms current in the breaker. c) The maximum possible D.C. component of the short circuit current in the breaker. d) The momentary current rating of the breaker. e) The current to be interrupted by the breaker. f) The interrupting KVA. [16]

Draw the characteristics of IDMT relay and explain the procedure of obtaining these characteristics. Derive characteristic equation of distance relay. Also draw the characteristics curves of Impedance and admittance relays. [8+8]

uW

3.a)

.in

1.a) b)

Draw the block diagram of static instantaneous over current relay. Also explain it’s operation. Explain the differential protection of transformer. [8+8] Derive expression for reflection & refraction coefficients. Write about Bewley’s lattice coefficients.

[8+8]

6.a) b)

Explain about attenuation and distortion of traveling waves. Discuss about effectively grounded system and ungrounded system.

[8+8]

7.a) b)

Discuss any one type of neutral grounding. What are the different types of lighting arrestors? Explain with diagrams.

[8+8]

8.a)

Classify the types of circuit breakers when the arc quenching medium is the criterion. With the help of block diagrams explain the principle of working of i) Minimum oil circuit breaker ii) Air blast circuit breaker. [8+8]

Aj

nt

5.a) b)

b)

--ooOoo--

Code No: RR320205

RR

SET-4

B. Tech III Year II Semester Examinations, December/January -2011-2012 POWER SYSTEMS - III (ELECTRICAL AND ELECTRONICS ENGINEERING)

Time: 3 hours

Max. Marks: 80 Answer any five questions All questions carry equal marks ---

2.a) b)

.in

b)

Draw the characteristics of IDMT relay and explain the procedure of obtaining these characteristics. Derive characteristic equation of distance relay. Also draw the characteristics curves of Impedance and admittance relays. [8+8] Draw the block diagram of static instantaneous over current relay. Also explain it’s operation. Explain the differential protection of transformer. [8+8]

or ld

1.a)

Derive expression for reflection & refraction coefficients. Write about Bewley’s lattice coefficients.

[8+8]

4.a) b)

Explain about attenuation and distortion of traveling waves. Discuss about effectively grounded system and ungrounded system.

[8+8]

5.a) b)

Discuss any one type of neutral grounding. What are the different types of lighting arrestors? Explain with diagrams.

[8+8]

6.a)

Classify the types of circuit breakers when the arc quenching medium is the criterion. With the help of block diagrams explain the principle of working of i) Minimum oil circuit breaker ii) Air blast circuit breaker. [8+8]

b)

Discuss the design features of current limiting reactors. Draw the block diagram of induction cup type relay also explain its working principle. [8+8]

nt

7.a) b)

uW

3.a) b)

A generator connected through a 3-cycle circuit breaker to a transformer is rated

10 MVA, 13.8 kv, with reactance of X d′′ =12%, X d′ =16%, and X d = 100% . It is operated at no load and rated voltage when a 3-phase short circuit occurs between the breaker and the transformer. Determine: a) The sustained short circuit current in breaker b) The initial symmetrical rms current in the breaker. c) The maximum possible D.C. component of the short circuit current in the breaker. d) The momentary current rating of the breaker. e) The current to be interrupted by the breaker. f) The interrupting KVA. [16]

Aj

8.

--ooOoo--