Two Marks

April 2015:

1.What are the functions of protective relays

2.Define selectivity of protective relaying

3.State the disadvantages of differential relay

4. Define operating time of a relay

5.what are the causes of over speed and how alternators are protected from it

6.Why busbar protection is needed

7.What are the two theories that are used to describe the arc extinction phenomena

8.Define the term current chopping

9.What is the special feature of vacuum CB

10.Write any two advantages of SF6 circuit breaker.

Nov 2014:

1. What are the functions of protective relays2. Define selectivity of protective relaying3. What are the merits of mho relay4. What is the need for protection zone in the system

5. What is the importance of bus bar protection6. What are the various possible faults in transformer7. Define recovery voltage8. Define rate of rise of restriking voltage9. What are the basic requirements of circuit breakers10. Why SF6 gas is preferred in circuit breakers

April 2014:

1.What is the need for protective scheme in power system

2.What is meant by relay margin

3.Write the principle of differential relays

4.What is a static relay? What are their essential components?

5.How is generator protected against unbalanced current

6.What is meant by relay coordination

7.What is RRRV

8.What are the types of tests performed on circuit breakers

9.What is the purpose of oil in oil circuit breakers

10.What are the advantages of HRC fuses

April 2013:

1.What is meant by R-X diagram2.What are the essential qualities of a relay3.What is a MHO relay4.What is static relay5.What are the limitations of Buchholz relay6.What are the basic protection are provided for every motor7.What are the two factors on which RRRV depends upon8.Define current chopping9.What are the ratings of circuit breakers10.What are the properties of SF6 gas

Nov 2013:

1.What is primary and backup protection2.Define pickup of a relay3.On what principle,distance relays are operating4.What is the function of negative sequence relay5.What is “inverted running” in alternators6.What is the operating principle behind carrier current protection of lines7.What is current chopping8.List out the advantages of HRC fuses

9.What are the drawbacks of using oil as arc quenching medium10.What are the different types of air blast circuit breakers

Nov 2013 : (4648235)

1.What is meant by primary protection and secondary protection2. Define the terms A.)pick-up value arid B.)reset value3. what is the principle of differential relays4.Draw the operating characteristics of an impedance relay on R-X plane5.What are the types of faults that are likely to occur in an alternator6.What is the importance of bus bar protection7.Define the term ‘rate of rise of re-striking voltage’.8.What are the tests to be carried out in circuit breakers to prove its ability9.Mention the advantages and disadvantages of oil as an arc quenching medium10.Write the desirable characteristics of fuse elements

Nov 2012:

1.What is called as primary protection2.What are the essential qualities of protective relay3.How is directional over current realy suitable for short circuit conditions4.What are the different types of relay used for protection5.What is pilot wire differential protection6.What is the carrier current protection scheme7.What are the primary duties of a circuit breaker8.What is breaking capacity9.What are the different types of air circuit breakers10.What are the demerits of SF6 circuit breaker

April 2012:

1.What is the need for relay protection2.What are the different types of relay3.What is negative phase sequence relay4.What are the different types of distance relays5.What is mho relay6.What is the protection schemes employed in AC machines7.What is current chopping8.Define RRRV

9.What are the different types of circuit breakers10.What are the merits of SF6 circuit breaker

April 2011:

1.What is known as symmetrical faults2.What is meant by R-X diagram3.What is meant by over current protection and list the application of over current relays4.Where are the types of electromagnetic relays5.Write the protective schemes for transformer protection6.Narrate the principle of carrier current protection of transmission lines7.Define RRRV8.Differential ac and dc circuit breaking9.What are the functions of oil in oil circuit breaker10.List the routine tests conducted on circuit breakers

Nov 2010:

1.What are the causes of short circuit currents2.What are the essential qualities of a relay3.List the application of differential relay

4.What is a MHO relay5.State the possible generator stator and rotor faults6.What is meant by single phasing in AC motor operation7.Write the arcing phenomena8.What is meant by current chopping9.What are the properties of SF6 gas10.Write the significance of routine tests in circuit breaker