Anna University , Chennai
Electrical Engineering Department
High Voltage Direct Current Transmission
2- MARKS
1. List out the applications of HVDC?
2. What are the types of transmission system?
3. State the comparison of AC & DC transmission system?
4. State the advantages in DC transmission?
5. State the disadvantage in dc transmission?
6. What are the types of DC link?
7. What is the need of smoothing reactor?
8. What are the factors to be considered for planning of Hvdc transmission?
9. Explain in two lines about choice of voltage level in DC transmission
10. What is DC breaker? How it will be useful?
11. Name the new modern trends in DC transmission.
12. What are the power semiconductor devices used in dc transmission?
13. Draw the converter station unit in hvdc transmission
14. How will overcome the disadvantages in dc transmission?
16- MARKS
1. For a fixed power transmission explain how the economic choice of voltage level selected in dc transmission system
2. Explain the technological development in control and protection , for better performance and reliability of dc transmission system
3. What are the different applications of dc transmission system? Explain them in detail?
4. With neat sketches explain the different kinds of dc link available?
5. Explain the comparison of AC and DC transmission in detail
6. Explain the application of dc transmission
7. Explain in detail about the planning of hvdc transmission?
8. Explain the technological development of modern trends in dc transmission
9. Explain the major components of a hvdc transmission in converter station unit?
10. State the advantages and disadvantages of dc transmission system with following economics, reliability, performance..
UNIT-2
2- MARKS
1. Define pulse number?
2. Draw the diagram graetz bridge circuit
3. Write the equation of ac current and dc voltage harmonics
4. What is choice of converter configuration?
5. Define peak inverse voltage?
6. Draw the schematic diagram of three & two valve conduction mode
7. Define twelve pulse converter with schematic diagram
8. What is meant by neglecting overlap in graetz in bridge circuit
16-MARKS
1. For a 3 phase 6 pulse gratez’s circuit draw the timing diagram considering overlap angle is less than 60 degree and without overlap for the following
a) Voltage across load
b) Voltage across any two pair of conduction valves
2. Explain the individual characteristics of a rectifier and an inverter with sketches
3. Draw the schematic circuit diagram of a 6 pulse gratez’s circuit and explain its principle of operation
4. Discuss in detail the effect of source inductance on hvdc system
5. Show the rating of the valve used in gratez circuit is 2.094Pd where Pd is dc power transmitted
6. Explain the effect of overlap angle on the performance of converter circuit
7. Explain the choice of converter configuration for any pulse number
8. Explain the analysis of 12 pulse converter with bridge rectifier
9. Explain the technique involved in harmonic elimination of bridge rectifier
10. Explain the analysis of two and three valve conduction mode
11. With detailed analysis of converter with steady state analysis
UNIT- 3
2- MARKS
1. Define Synchronous Condenser
2. What will be the current regulation in inverter side?
3. Define transformer tap changing
4. State the transmission characteristics with rectifier and inverter
5. Define firing angle control
6. What is uncompounded inverter?
7. What is equidistant pulse control?
8. How will you protect against dc line faults?
9. Draw the characteristics curve for inverter compounding?
10. What are the types of transformer tap changer?
11. State the features of on load tap changer?
12. Draw the characteristics curve for inverter compounding?
13. For the operating point of two characteristics. state the constant current compounding?
14. Draw the voltage current characteristics of converters with compounding?
16-MARKS
1. Explain the individual characteristics of a rectifier and an inverter with sketches
2. Explain in detail about the transformer tap changer with its types
3. Explain in detail about the converter control characteristics of hvdc system
4. Draw and explain the inverter and rectifier compounding characteristics with constant voltage and current curve.
5. Explain the uncompounded inverter with neat sketches
6. Explain in detail the concept of reactive power requirement in hvdc converters
7. Explain in detail about current regulation from the inverter side
8. With the block diagram, discuss the principle of operation of a basic power controller
UNIT-IV
2- Marks
1. Define Harmonic.
2. How harmonics are generated?
3. Write the characteristics of Harmonics?
4. Write the fundamental components of harmonics with a order of ‘h’?
5. Define AC filter?
6. Define DC Filter?
7. What are the components present in AC & DC filter?
8. What are the interference produced in the communication lines.
9. Define total harmonics distortion?
10. How can we avoid the interference occur in communication line?
11. Define Telephone influence factor.
12. What are the types of AC filters & Dc?
13. Define single tuned filter?
14. How will protect the filter?
16-Marks
1. Write short notes on the following:
(a) Telephone influence factor
(b) Harmonic distortion
2. What are the filter configuration that are employed for HVDC Converter station ? Give design aspect of one such filter.
3. Derive an equation for harmonic voltage and current for single tuned filter and discuss the influence of network admittance.
4. Give a detailed account of design aspects of following filters
(a) Single tuned filter
(b)Double tuned filter
5. It is required to eliminate harmonics of order 10 and below 10 other than fundamental in a 12 pulse converter suggest and derive an equation?
6. Explain in detail about different types of transformer tap changing.
UNIT-V
2-Marks
1. Define Dc Cables?
2. State the basic physical phenomenon arising in DC insulation?
3. What is meant by dielectric constant in DC cable?
4. Define dielectric stress?
5. Compare the economics of Dc cables with AC cables.
6. Define system simulation.
7. What is meant by HVDC system simulation?
8. Draw the block diagram of system simulation.
9. Distinguish AC cable vs DC cable transmission?
10. State the number of tools used for simulation of dynamic system.
11. What are the requirements for good simulation tool?
12. What are the two approaches are available in transient analysis of simulation?
16-Marks
1. Describe the comparison of economics of AC and DC.
2. Explain in detail about the modeling of HVDC system for digital dynamic simulation.
3. Explain in detail about HVDC system simulation
4. Describe the philosophy and tools used in HVDC simulation.
5. Explain the Dielectric stress in cables.
6. Describe the Physical phenomenon arising in DC insulation.
