EX-702-B HVDC and FACTS - Dec 2024 Question Paper

Under each question, How to answer lists the points an answer should cover, outlined by CampusPrep from the syllabus. Check the details against your textbook.

1. 7 Marks
   aWhat are FACTs controllers? Discuss.
   How to answer

   • Definition of FACTS controllers
   • Need for FACTS in power system control
   • Classification - series, shunt, combined
   • Examples of each type with function
2. 7 Marks
   bWhat is the principle of conventional reactive power compensators?
   How to answer

   • Concept of reactive power compensation
   • Conventional devices - capacitor, reactor, synchronous condenser
   • Principle of voltage support by reactive injection
   • Limitations of conventional methods
3. 7 Marks
   aDiscuss TCSC in detail with their advantages and disadvantages.
   How to answer

   • Construction and configuration of TCSC
   • Modes of operation - capacitive, inductive, bypass
   • Advantages in power flow and stability
   • Disadvantages - harmonics, cost, complexity
4. 7 Marks
   bDraw the schematic diagram of unified power flow controller.
   How to answer

   • Structure of Unified Power Flow Controller
   • Series and shunt converter with DC link
   • Neat labelled schematic diagram
   • Function in P-Q control
5. 7 Marks
   aDraw the layout of HVDC converter station and discuss various equipments.
   How to answer

   • Single line layout of HVDC converter station
   • AC side, converter transformer, valves, filters
   • DC side smoothing reactor and electrodes
   • Function of each equipment
6. 7 Marks
   bWhat are merits and demerits of HVDC Transmission System?
   How to answer

   • Merits - no stability limit, less losses, asynchronous interconnection
   • Merits - power control, less corona, economical for long distance
   • Demerits - costly converters, harmonics, reactive power demand
   • Demerits - difficult circuit breaking, commutation failure
7. 7 Marks
   aWhat is SSSC? What is its use? Explain its operation.
   How to answer

   • Definition of SSSC - Static Synchronous Series Compensator
   • Use in series compensation and power flow control
   • VSC based operation with quadrature voltage injection
   • Operating modes - capacitive and inductive
8. 7 Marks
   bDiscuss the operation of STATCOM in compensation.
   How to answer

   • Principle of STATCOM as shunt VSC compensator
   • Reactive power exchange by voltage magnitude control
   • Operation in capacitive and inductive modes
   • Role in voltage regulation and compensation
9. 7 Marks
   aDiscuss ac and dc filters in control of HVDC system.
   How to answer

   • Need for AC and DC filters in HVDC
   • Types of AC filters - tuned, high-pass
   • DC filter configuration and function
   • Control aspect for harmonic elimination
10. 7 Marks
    bExplain the principle of control of HVDC system.
    How to answer

    • Basic principle - constant current / constant extinction angle control
    • Rectifier and inverter control characteristics
    • Current, voltage and power control loops
    • Tap changer and firing angle control
11. 7 Marks
    aCompare the series and parallel MTDC.
    How to answer

    • Configuration of series MTDC
    • Configuration of parallel MTDC
    • Comparison on control, reliability, losses
    • Applications suitability
12. 7 Marks
    bExplain multiterminal DC systems and applications where it is utilised.
    How to answer

    • Definition and structure of multiterminal DC systems
    • Types - series, parallel, hybrid
    • Control and protection aspects
    • Applications - renewable integration, interconnections
13. 7 Marks
    aDraw the converter control characteristics.
    How to answer

    • Rectifier constant current characteristic
    • Inverter constant extinction angle characteristic
    • V-I diagram with operating point
    • Effect of control on power transfer
14. 7 Marks
    bDiscuss the types of harmonics in HVDC system.
    How to answer

    • Source of harmonics in converters
    • Characteristic vs non-characteristic harmonics
    • AC side and DC side harmonics
    • Effects and mitigation
15. 14 Marks
    Write short notes on any two:

    1. a)SVC
    2. b)Types of DC links in HVDC system
    3. c)Power reversal in HVDC system
    How to answer

    • SVC - configuration, TCR+TSC operation and uses
    • DC links - monopolar, bipolar, homopolar types
    • Power reversal - voltage polarity reversal principle and control
    • Diagrams and applications for any two