JAWAHARLAL
NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
M.Tech I Semester Regular Examinations
March/April 2010
HVDC TRANSMISSION
(ELECTRICAL POWER ENGINEERING)
Time: 3hours Max.Marks:60
Answer any five questions
All questions carry
equal marks
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1. a) Discuss the
various applications of HVDC transmission.
b) What are the
factors to be considered in planning for HVDC transmission?
2. How is a suitable
voltage level chosen for HVDC transmission?
3. Define pulse
number, thyristor PIV rating and index of valve utilization and
transformer
utilization factor.
4. Derive a formula
for average DC voltage of Graetz circuit taking overlap into
account.
5. a) Discuss briefly
the principle of DC link control.
b) Explain firing
schemes adopted in firing angle control along with their relative
merits and demerits.
6. Discuss the
starting and stopping techniques of DC link in a HVDC transmission
system.
7. How are the
signals derived from AC system used to control the DC link to
improve the overall
performance?
8. Discuss the causes
of over voltages in HVDC converter station and methods to
protect the system
against them?