Uttar Pradesh Technical University (UPTU) 2009-7th Sem B.Tech Electrical Engineering --ester-SwitchGear and Protection - Question Paper
B.Tech
(VII)Odd Semester Theory Examination(2009-2010)
Switch Gear and Protection
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Printed Pages: 3 TEE701
(Following Paper ID and Roll No. to be filled in your Answer Book) Roll No.
PAt>emp : 0260
(SEM VII) ODD SEMESTER THEORY EXAMINATION 2009-10 SWITCHGEAR & PROTECTION
Time : 3 Hours] [Total Marks : 100
Note : Attempt all questions.
1 Attempt any four of the following : 5x4=20
(a) "Relay is the brain of protection". Justify this statement using trip circuit.
(b) Describe about primary and backup protection.
What is meant by time graded over current protection ?
(c) Discuss about any four major qualities a relay should possess.
(d) Draw a neat diagram of gas actuated relay.
What is its location and use in the device ?
(e) Discuss about wattmetric type induction disc relay in detail
(f) Define the following :
(i) Pick-up
(ii) Drop out
(iii) Reset
(iv) Interlock
(v) Blind spot.
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2 Attempt any two of the following . 10x2=20
(a) Discuss about phase and amplitude comparators in detail.
(b) What is a distance relay ? Draw its characteristics. How is directional feature added with over current relays ? Why is it required ?
(c) Compare a static relay with electromagnetic relays.
3 Attempt any two of the following : 10x2=20
(a) Describe different types of distance relays used for protection of transmission lines. Which one is the best and why ?
(b) Describe pilot wire protection, its merits and demerits in detail.
(c) How is a bus bar protected ?
4 Attempt any two of the following : 10x2=20
(a) What are the problems associated with short line interruption ? How is the problem eliminated 9
(b) Describe about the direct and indirect testing procedure for a circuit breaker.
(c) Discuss about RRRV. Draw a neat diagram to show the voltages and current during relay and circuit breaker operations. Discuss about active recovery voltage, relay operating time, circuit breaking time and circuit making time.
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Attempt any two of the following : 10x2=20
(a) Describe the construction and operation of a minimum oil circuit breaker.
(b) Draw appropriate diagrams to show the complete operation of a sf6 circuit breaker.
Give the merits of sf6 circuit breakers.
(c) Give a complete protection scheme for Alternator.
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