Switchgear and Protection 22524 MSBTE Important Question for Exam

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 Switchgear and Protection 22524 MSBTE Important Question for Exam


22524 IMP

Switchgear and Protection is a field of study that deals with the design and operation of electrical power systems, including the protection of electrical equipment and circuits against faults and overloads. Some topics that may be covered in an MSBTE Switchgear and Protection exam include:

  • The principles and characteristics of electrical power systems, including the generation, transmission, distribution, and utilization of electrical energy
  • The types and functions of electrical switchgear, including circuit breakers, fuses, relays, and protective devices
  • The principles and methods of protection against electrical faults, including overcurrent, earth fault, and short-circuit protection
  • The principles and methods of protection against overloading of electrical equipment and circuits, including thermal and magnetic protection
  • The selection and coordination of protective devices to ensure reliable and safe operation of electrical power systems
  • The testing and maintenance of electrical switchgear and protective devices
  • The safety rules and regulations governing the operation of electrical power systems
  • The principles and techniques used in the design and planning of electrical power systems, including load flow analysis, short-circuit calculations, and protective device coordination.
  • NOTE: These are not formal MSBTE Questions We Provide Important Practice Questions for Students to Score Good Marks in Exam and this Questions is based on Important Topics of Syllabus and Repeated Ones. So, with the help of this we help student to Not get KT / or /They will Not get Fail in Exam.

To prepare for an MSBTE Switchgear and Protection exam, it is important to review and understand the material covered in your classes and to practice applying your knowledge through practice problems. It may also be helpful to review past exam questions, if they are available, and to work with your classmates or seek assistance from your instructors if you have any questions or need clarification on any topics.

a.     State any for causes of faults in power system.

b.     State the function of current limiting reactor.

c.     State the difference between normal and abnormal conditions in power system.

d.     List any two advantages and two disadvantages of vacuum circuit breaker.

e.     State the factors to be considered while selecting MCCB for motor protection.

f.      State the need of insulation coordination


a. Two 11kV, 3 phase, 5000kVA generators each having reactance of 20% operate in parallel. The generators supply power to transmission line through 3000kVA transformer of ratio 22kV/33kV having leakage reactance of 6%. Calculate Fault kVA on H.T. side of transformer.

b. Compare HRC fuse and Circuit breakers as interrupting devices on any four points.

c. Describe with neat sketch the arc extinction in SF6 circuit breaker.

d. Define following terms related to CB:

i) Rated normal current ii) Rated breaking current:

iii) Short time rating iv) Symmetrical breaking current

e. With the help of neat sketch explain the working of ELCB.


a. Define the terms related to Protective Relay :
(i) Selectivity (ii) Sensitivity

b. State the principle of distance relaying.

c. State any four advantages of static over current relay over electromagnetic relay.

d. State the need of over voltage relay in power system.

e. List any four faults occuring in alternators.

f. State the difference between short circuit and overload.

a. With a neat sketch explain solenoid type over current relay.

b. State any four salient features of microprocessor based protection relay. Draw block diagram of microprocessor based over current relay.

c. Explain the conditions for setting up negative phase sequence currents in an alternator. Draw the protective scheme to detect them and operate the CB.

d. A three phase 66/11 kV, star-delta connected transformer is protected by Merz-Price protection. The CTs on LT side have a ratio of 420/5. Find the ratios of the CTs on the HT side. Draw the neat labelled connection diagram of the complete scheme.

e. Describe with neat diagram, the time graded over current protection of transmission line. State its drawbacks.

a)     Classify current limiting reactors based on location.

b)     Differentiate between symmetrical and unsymmetrical faults .(any two points)

c)     Define i) making capacity ii) short time rating of circuit breaker.

d)     State any two disadvantages of static relays.

e)     List any four faults occurs in alternator.

f)      State any four abnormalities in induction motor.

g)     List protection schemes used for the bus-bar.

1. Compare the MCCB with ELCB on any three points. State the application of the RCBO.

2. Explain time-current characteristics of IDMT relay.

3. List four limitations of differential protection scheme for transformer.

4. Explain with sketch protection of 3-phase induction motor during single phasing.

5. Explain with neat sketch fault bus protection scheme.


a)     With the help of suitable diagram explain the importance of back-up protection.

b)     Define the following terms related to current interrupting devices:

i)  arc voltage, ii) re-striking voltage, iii) recovery voltage and iv) RRRV

c)     Explain PSM and TSM related to protective relays.

d)    A 220V/22kV three phase transformer is connected in star/ delta. The protective transformers on 220V side have current ratio of 400/5. Calculate the CT ratio on 22kV side.





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