Name of the College : SREE CHAITANYA COLLEGE OF ENGINEERING
University : JNTUH
Department : ELECTRICAL AND ELECTRONICS ENGINEERING
Subject Code/Name : 07A70204/HVDC TRANSMISSION
Year/Sem : IV/I
Website : scce.ac.in
Document Type : Model Question Paper
Download Model/Sample Question Paper : https://www.pdfquestion.in/uploads/scce.ac.in/4926-07A70204-HVDCTRANSMISSION.pdf
SCCE HVDC Transmission Question Paper
Code No: 07A70204
R07 Set No. 2
IV B.Tech I Semester Examinations,December 2011
Related : Sree Chaitanya College Of Engineering 07A70206 High Voltage Engineering B.Tech Question Paper : www.pdfquestion.in/4925.html
Time: 3 hours
Max Marks: 80
Answer any FIVE Questions :
All Questions carry equal marks :
1. (a) Explain the eects of single commutation failure in converter.
(b) Explain briefly the factors on which recovery from a commutation failure depends. [8+8]
2. (a) Explain the causes of reactive power absorbed by HVDC converter substation.
(b) With a neat sketch, explain about Thyristor controlled Reactor. [8+8]
3. (a) Compare simultaneous and sequential methods of power flow analysis.
(b) Draw the flow chart for AC/DC load flow. [8+8]
4. (a) Explain briefly about dierent types of HVDC links.
(b) Compare the HVDC transmission HVAC transmission with reference to following factors:
i. Economics
ii. Technical performance
iii. Reliability. [8+8]
5. Draw the loci of Network impedance and filter impedance and analyze the impact of network impendence or admittance on the design of single tuned filter. [16]
6. Why are harmonics generated in HVDC converter and what are the problems associated with the harmonius. Suggest some remedial measures. [16]
7. (a) With the help of a circuit diagram, analyse the operation of 3-valve conduction mode and derive the expression for the currents of the incoming and outgoing valves during commutation.
(b) Derive the expression for DC voltage and voltage drop due to overlap and hence deduce the equivalent circuit of bridge rectifier.
(c) Prove that the delay angle is same as the power factor angle in case of the controlled rectifier. [16]
8. (a) A HVDC link is operating with 175 KV AC line voltage at the rectifier. When the DC current is 1100 Amps, the rectifier delay angle is 100 and inverter extinction angle is 200. The resistance of the line is 23 ohms and the commutating reactances of the rectifier and inverter are 22 ohms and 21 ohms. Calculate the DC voltages at the rectifier and inverter terminals and the AC line voltage at the inverter.
(b) For a two terminal DC link, explain the complete control characteristics of rectifier and inverter stations. [8+8]
Code No: 07A70204
1. (a) What are the desired features of control? Explain in detail.
(b) What is equivalent pulse control? What are the advantages of equivalent pulse contur over individual phase control? [8+8]
2. (a) Analyse a bridge rectifier with overlap angle greater than 600. Derive the relevant equations and draw the necessary graphs.
(b) Draw the equivalent circuit of a rectifier and mention its components. [8+8]
3. Describe the schematic diagram of a HVDC link, mentioning all the key elements. [16]
4. (a) Draw the schematic diagram of a typical HVDC link showing the major equipment at either ends.
(b) Draw a neat diagram of a Bipolar DC link. What are its advantages? [8+8]
5. (a) Write short notes on Alternate control strategies.
(b) Describe the various types of reactive power sources used in HVDC transmission. [8+8]
6. What are the various sources of harmonics generation in a HVDC line? Describe how a double tuned filter can be designed for a HVDC system. [16]
7. Derive the relation ship between pulse converter and harmonics generated. [16]
8. (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) Give the necessity of smoothing reactor in a HVDC system and list out main functions of it. [10+6]
Set No.1 :
1. (a) Briefly explain the different types of DC links and why homo polar links are mostly used?
(b) Explain the importance of a HVDC converter station, in the whole scheme of HVDC transmission. [8+8]
2. How is Total Harmonic Distortion estimated in a circuit? Explain the relevance of THD to a HVDC system.