JNTU Exam Papers,IV B.Tech II Semester Supplimentary Examinations,HVDC Transmission June 2007
1. Write Technical notes on the following.
(a) Back-to-Back HVDC coupling system.
(b) Back to back DC link along with AC feeder.
2. (a) Clearly explain how harmonics are produced and obtain the expression for rms value of the fundamental component of the current.
(b) Obtain a relation between firing angle and power factor angle in a 3φ bridge rectifier.
3. Draw and explain a block diagram of the Hierarchical levels of controls of HVDC transmission system.
4. Discuss the various sources of reactive power for HVDC converters.
5. (a) Compare simultaneous and sequential methods of power flow analysis.
(b) Draw the flow chart for AC/DC load flow.
6. (a) Explain the fault clearing process in H.V.D.C. poles. Explain how are the H.V.D.C. equipment protected against prolonged short circuit currents though there is no H.V.D.C. circuit breaker on H.V.D.C. pole side.
(b) Explain the protection provided for DC line .
7. Why are harmonics generated in HVDC converter and what are the problems associated with the harmonics. Suggest some remedial measures.
8. Mention the names of various types of filters that are used in HVDC converter station and draw their impedance characteristic and configuration. Give design aspects of one filter.