SESSION PLAN Sl. Topics in JNTU Syllabus Modules and Sub Modules UNIT-III 9 Principal of DC link control Introduction Steady state equivalent circuit of a 2 terminal DC link Lecture L20 Suggested Books 10 Converters control Basic characteristics L21 Characteristics Modification of the control characteristics mode stabilization voltage dependant current limit L22 System control hierarchy L23 11 Firing angle control Individual phase control L24 Equidistant pulse control L25 12 Current and extinction angle control 13 Starting and stopping of DC link; power control 14 Reactive power requirements in steady state, conventional control strategies Block diagram of current L26 controller Energization and deenergization of L27 a bridge Start-up of DC link L28 Power and auxiliary controller L29 UNIT-IV Introduction Conventional control strategies variation of Qd with Pd 15 Alternate control strategies Operating region of a bridge in Pd-Qd plane phasor diagram Alternate reactive power characteristics Forced communication 16 Sources of reactive power Reactive power sources at a converter bus Static VAR systems thyristor controlled reactor Thyristor switched capacitor Reactive power control during transients L30 L31 L32 L33 L34 L35 UNIT-V 17 Modeling of DC links, DC Introduction T1-Ch11 network, DC converter, controller equations DC network modeling DC converter modeling L36 Controller equations L37 T1-Ch11 18 Solution of DC loadflow, P.U. DC load flow discussion per unit T1-Ch11 L38 system for DC quantities system for DC quantities 19 Solution of AC-DC powerflow Simultaneous method, sequential T1-Ch11 L39 method Sl. Topics in JNTU Syllabus Modules and Sub Modules Lecture Suggested Books UNIT-VI 20 Converter faults Introduction T1-Ch5, T2-Ch17 General faults communication failure L40 DC converter modeling Arc through misfire current T1-Ch5, T2-Ch17 L41 extinction short circuit in a bridge 21 Protection against over current Protection against over currents L42 T1-Ch5, T2-Ch17 and over Disturbance on the AC side T1-Ch5, T2-Ch17 voltage in converter station Disturbance on the DC side L43 Internal converter disturbance Protection against over voltages L44 T1-Ch5, T2-Ch17 Remarks Remarks 1
Sl. Topics in JNTU Syllabus Modules and Sub Modules Lecture Suggested Books Over voltage protection in a converter station 22 Surge arresters, smoothing Surge arresters, smoothing T1-Ch6, T2-Ch17 L45 reactors, DC breakers reactors Basic concept of DC circuit T1-Ch6, T2-Ch17 interruption characteristics and L46 types of DC breakers 23 Audible noise, space Audible noise, space T1-Ch6, T2-Ch17 L47 charge field charge (Ion flow) field 24 Corona effects on DC lines, Corona effects T1-Ch6, T2-Ch39 radio interference Corona loss Radio interference L48 UNIT-VII 25 Generation of harmonics, Introduction characteristics Characteristics harmonics,calculation of AC harmonics,calculation of AC L49 harmonics harmonics 26 Non-characteristics harmonics, Effect of firing angle errors L50 adverse effects of harmonics Effect of unbalanced voltages 27 Calculation of voltage Fourier analysis for voltage and L51 andcurrent harmonics, effect of current harmonics calculation pulse number on harmonics Effect of pulse number on the L52 order of harmonics UNIT-VIII 28 Types of AC filters, design of Single turned filter L53 single tuned filters Design of a single tuned filter Minimum cost tuned filters L54 29 Design of High pass filters. Derivation for high pass filter L55 Remarks 2
EE 4105 - H.V.D.C. TRANSMISSION ASSIGNMENT QUESTIONS UNIT I 1. Explain, why DC transmission is economic than AC transmission? 2. Compare Technical performance of AC and DC Transmission system. 3. Why DC transmission is reliable than AC Transmission. 4. Explain why generation and distribution is always AC? 5. Describe the factors that initial the development of DC transmission. 6. Explain what are the problems associated with the use of AC transmission system? 7. Explain Disadvantages of DC Transmission? and how it overcome? 8. Write a short note as a) Energy availability, 9. Give some applications of DC transmission. 10. Explain why AC Transmission is used in submersing and under ground waters. 11. Explain why bipolar links are most commonly used. 12. Draw the Twelve pulse converter unit and explain cooling methods of values. 13. Write a short note on protecting methods of valves. 14. Explain different converter transformers configuration 15. Write short note as Modern trendy in DC Transmission. 3
UNIT II 1. Write a short note on pulse number. 2. Explain choice of converter configuration for a given pulse number. 3. Define commutation group? Explain how value a line is depends on commutation group? 4. Explain how transformer rating is depends on commutation group and show that transformer S V I tv utilization factor 1.481( ifq 3) d 0 5. Show that six pulse converter is best graetz circuit. d 6. What are the assumption made in the analysis of HVDC converters. 7. What is mean by overlap and give what are the factors caused by overlap 8. Explain converter operation (without overlap) and draw the DC voltage waveforms for different fixing angles. 9. Explain how reactive power requirements are increased as fining angle is increase from zero. 10. Draw and explain the wave form of divert voltage and the value current during commutation for rectifier and inverter when converter operated in mode 1 opeation. 11. Obtain the average direct voltage when converter operates in mode I 12. Explain how the harmonics in the direct voltage are altered due to overlap. 13. Explain, characteristics of rectifiers. 14. Explain, characteristics of Inverters. 15. Explain, characteristics of Twelve pulse converter. 4
UNIT III 1. Describe the principles of DC link control. 2. Explain control characteristics of rectifier and inverter. 3. Explain what are the requirement which necessities the modification of the control characteristics. 4. Explain how will perform the control function required for HVDC link using hierarchical control structure. 5. Explain how equidistant pulse control scheme is better than individual phase control. 6. Explain drawbacks of IPC Scheme 7. Explain pulse frequency control. 8. Explain different methods of start up of DC links. 9. Explain different control strategies. 10. Write a short note on sources of reactive power. 11. What are the different types of SVS schemes and Explain. 12. Explain why reactive power control need in HVDC system. 5
UNIT IV 1. Write short note on modeling of DC network. 2. Writer short note on modeling of DC converter 3. Write a short note as DC load flow. 4. Write a short note as pavrit system for DC quantities. 5. Explain Simultaneous Solution Methodology for AC - DC power flow. 6. Explain alternating solution methodology for AC DC power flow 7. Compare Simultaneous and sequential methodology. 8. Draw flow chart of AC/DC load flow and Explain. 9. What are types of faults that can occur in converters and write a short note on different faults. 10. Explain commutation failure in inverters. 11. Explain short circuits in a converter station. 12. What are the factor that must be considered in designing a protection systems against over current. 13 What are the basis factors to change the over voltages and what are the types of over voltages. 6
UNIT V 1. What are the problems associated with the injection of harmonics. 2. Write a short note on characteristic harmonics and obtain the DC voltage harmonics for the furies analysis of DC voltage waveforms 3. What are the factor caused by Non characteristic harmonics in HVDC systems. 4. Explain the effect of firing angle errors on non-characteristics harmonics. 5. Explain the effect of unbalanced voltages on non-characteristics harmonics. 6. What is the criteria of Design of filters and how can be measured by filters performance. 7. Write design aspects of single tuned filters. 8 Write a short note on protection of filters. 9. Write design aspects of High pass filters. 10. Write a short note on double tuned filters. 11. Draw the impedance characteristics as a function of the frequency of different types of filters. 12. Write a short note on DC filters. 7