sub - Switchgear and protection Utu previous year question papers

B.tech Examination papers dec 2014
sub - Switchgear and protection
Utu previous year question papers
uttarakhand technical university previous question papers

Time : 3 hrs
Q1: Attempt any four :

1. Explain static relay and write its merits and demerits.
2. Explain electromagnetic impedance relay.
3. What are the various types of over current relays? Discuss their are of applications.
4. Explain Directional Over-current relay?
5. The current rating of a relay is 5A. PSM=2, TSM=0.3, CT ratio=400/5, fault current= 4000A. Determine the operating time of the relay. At TMS= 1, operating time various PSM are:
   PSM=                                2         4        5        8        10        20
   operating time in seconds=  10       5        4        3       2.8        2.4

Q2: Attempt any four:

1. Explain thermal relay and its advantages?
2. Enlist the essential qualities of relay use in protection scheme?
3. What do you understand by a zone of protection? Discuss various zones of protection for a modern power system.
4. What is amplitude compactors and explain any one of it?
5. Write short notes on attraction induction type relay?
6. Derive an expression for torque produced by an induction relay.

Q3: Attempt any two parts:

1. Describe percentage differential protection and under-grounded neutral system.
2. Explain the Principle and construction of SF6 circuit breaker.
3. Describe the protection employed against loss of excitation of an alternator.

Q4: Attempt any two:

1. Discuss the time- graded over current protection for
   a) Radial feeders
   b) Parallel feeders
2. Describe the differential pilot wire method of protection of feeders.
3. What is carrier current protection? For what voltage range is it used for the protection of transmission lines? What are its merits and demerits?

Q5: Attempt any two:

1. Explain the terms: restriking voltage, recovery voltage and RRRV. Derive expression for restriking voltage and RRRV in terms of system voltage, inductance and capacitance.
2. Write short note on testing of circuit breakers.
3. What are the types of fault on transformers?

B.tech Examination papers dec 2014 sub - Switchgear and protection uttarakhand technical university previous year question papers uttarakhand technical university last year question papers utu previous year question papers on step4success