Electrical Substation Practices Sample Question Paper I Scheme MSBTE Electrical Engineering Group

Q.1 Attempt any Five of the following.
(10 Marks)

a) Classify substations based on voltage level.
b) State the need of pole mounted distribution substation.
c) Illustrate the function of isolator switch.
d) List out any four protective devices needed in 132/33 kV substation.
e) List the material used to enhance earthing resistance in rocky land.
f) State the need of gas insulated sub station
g) List any two advantages of GIS substation.

Q.2 Attempt any Three of the following.
(12 Marks)

a) With neat diagram explain the working of configured grid substation.
b) Describe the construction and working of swing out (Drop out) fuse.
c) Explain the precautions taken while carrying out maintenance of capacitor bank in
substation.
d) Explain working and need of capacitor voltage transformer with neat sketch.

Q.3 Attempt any Three of the following.
(12 Marks)

a) List out personal protective equipments (PPEs) used while entering the substation with
their respective application
b) Draw neat labeled single line diagram of pole mounted substation, state the function of
protective devices used for protection.
c) Summarize the activities to be carried out for maintenance of oil circuit breaker.
d) Distinguish between system earthing and equipments earthing.

Q.4) Attempt any Three of the following.
(12 Marks)

a) Explain the methods of improving earth resistance.
b) Difference between conventional earthing and chemical earthing.
c) Describe the procedure to perform voltage break down test of transformer oil.
d) List the precautions taken while carrying out preventive maintenance of GIS.
e) Define partial discharge and explain its effect on performance of GIS

Q.5) Attempt any Two of the following.
(12 Marks)

a) Determine the ratings of LA, CT, PT, DO fuse and circuit breaker (with Justifications)
for mounting of 500kVA, 11/0.4kV plinth mounted substation.
b) Illustrate the procedure to carry out preventive maintenance of 33/ 11 kV air break
circuit breaker.
c) With neat diagram explain the working and advantages of power line carrier
communication.

Q.6) Attempt any Two of the following.
(12 Marks)

a) i) Differentiate between mat earthing and plate earthing
ii) list the merits of mast protection.
b) Describe the causes of hot spot formation in transformer and state the methods of
identification.
c) Elaborate the causes of fire in gas insulated substation and list firefighting equipments
mainly used based on the reason of fire.