Jawaharlal Nehru Technological University Kakinada 2010-2nd Sem M.Tech Electrical & Electronics Engineering Supplementary s Power System Protection with Static Relays (EEE-Power Systems

Subject Code: B5604
M.Tech II Semester Supplementary exams June 2010
Power System Protection with Static Relays
(EEE-Power Systems (HV))
Time: three Hours Max Marks: 60
ans any 5 ques. All ques. carry EQUAL marks
1. a) elaborate the advantages of static relays over electromagnetic relays.
b) discuss elaborate amplitude and phase comparators.
2. a) explain the operating principle of a rectifier bridge phase comparator.
b) discuss the principle of a coincidence circuit for phase comparator.
3. a) elaborate the different kinds of over current relays? explain their area of
applications.
b) discuss the static directional over current relays with neat block diagram.
4. a) explain the current graded over current protection scheme.
b) discuss the over current protection scheme of ring main system.
5. a) elaborate various kinds of distance relays. Compare their merits and
demerits.
b) What is an angle impedance relay? explain how its characteristic is realized
using the phase comparison technique.
6. a) discuss the need of conic characteristics.
b) explain the hyperbolic characteristics of distance relays.
7. define the polyphase differential relay using sequence detectors.
8. Draw the neat sketch of static differential protection of 3 phase transformer
and discuss its operating principle.

Earning:   Approval pending.