Rajasthan Technical University 2009-8th Sem B.E : Electrical Engineering (B.Tech- ) Static Protective Relays - Question Paper
Rajasthan tech. University kota
Electrical Engineering (B.Tech. - semester 8)
Static Protective Relays
Paper III
8203
IV B.E. (Mil SEMESTER) (MAIN/BACK) EXAMINATION, 2009
(New Four Year Semester Scheme)
(Branch : Electrical Engineering]
Paper III STATIC PROTECTIVE RELAYS
Time Allowed : Three Hours Maximum Marks 80
;7) No .supplementary answer-book will be given to any candidate. Hence the candidates should write the answer precisely in the Main answer-book only.
(2) All the parts of one question, should be answered at one place in the answer-book. One complete question should not be answered at different places in the answer-book.
Turn over
i
A ttempt any five questions.
All questions carry equal marks.
1. (a) What are the basic elements of a protection scheme using micro-computer? Describe the function of each element 10
(b) Discuss the advantages of digital protection. 6
2. (a) Explain the vollage and current comparators for
two inputs. __ , 8
(b) Explain the duality between phase and amplitu comparators. 8
1
3. (a) Describe the operation of Hall effect relay used -as
a phase comparator. Describe two types of static amplitude comparators. 10
(b) What are the merits and demerits of static relay over electro-magnetic relay? 6
4. (a) With the help of neat diagram explain the
principle of static differential relay. 10
(b) Show that the polar curve of a biased differential relay using a static comparator is a circle. 6
5. Derive the input quantities necessary to obtain quadrilateral distance relay characteristic using
(i) Asymmetric phase comparator 8
(ii) Phase sequence detector. 8
6. What type of static protective scheme is employed for protection of large transformers? How can it take care
of
(/) Magnetizing inrush current
8
(it) Saturation of currerit transformer magnetic circuit. 8
7. (a) Explain the basic frequency sensitive circuit. 8
(b) With the help of block diagram and waveforms, explain the underfrequency measuring relay. 8
8. Write short notes on any two of the following:
(i) Auto reclosing
(ii) Voltage regulators
(hi)' Static protection for motors
(iv) Static protection (differential) for Bus Zone. 8+8
IV BE 8203 3 2300
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| Earning: Approval pending. |
