Biju Patnaik University of Technology 2008-7th Sem B.Tech (B Tech),ester power system protection - Question Paper
B tech (BPUT) seventh semester power system protection ques. paper
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Total number of printed pages -4 B, Tech
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Seventh Semester Examination - 2008 POWER SYSTEM PROTECTION Full Marks-70
Time: 3 Hours
Answer Question No. 1 which is compulsory and any five from the rest.
The figures in the right-hand margin indicate marks.
1. Answer the following questions : 2x10
How doesiinearcoupierdifferfrom ordinary CTs ?
ilWhat is magnetising inrush current in Transformer ?
What are incipient faults in Transformers?
p.T.O.
{iv) Wfoal is liefd suppression in connection with Alternator 7
v(v)' What is hybrid comparator ?
<wij Wme the essentia! components of a static relay.
HvilJ What are the advantages ot numerical relay over conventional relays ?
Svtffj Draw the block diagram at a Numerical relay.
*4cfDiscuss the role of anti-aliasing filter in numerical proteclion.
Explain the need for a three stepped distance protection of a transmission line.
Discuss about synthesis of Quadrilateral Distance Relay. 10
3. Explain the FI R and 11R filters with neat diagram and give a comparison between them. 6 +4
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<aj Describe the realisation of a directional overeurrent relay using a microprocessor
6
Mb) Draw the three step MHO characteristic for two cases 4
(i) 3 zone unit placed at near end A
(ii) 3ra zone unit placed at remote end B.
Discuss in detail the phase comparison carrier current Protection. 10
6, (a) Discuss about Modified Differential Protection for Generators. 6
* A 3 phase, 10 MVA, 6.6 kv star connected generator is protected by the current balancing system of Protection. If the ratio of current transformers is 1000/5, the minimum operating current of the relay is 0.5A and the neutral point earthing resistance is 5,Qt determine the percent-
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age of each phase of stator winding, which is protected against earth faults when the machine is operating at normal voltage.
4
v/7. Discuss about Percentage Differential Relay with Harmonic Restraint in connection with Transformer Protection, 6
(B) Discuss about incipient faults in Transformers, 4
(a) Discuss about Differential Protection of Busbars. 5
(b) Discuss about Protection of Parallel feeders and ring mains. 5
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