www.Vidyarthiplus.com VALLIAMMAI ENGINEERING COLLEGE SRM Nagar, Kattankulathur – 603 203. DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING Question Bank Programme: ME Subject: PX7204‐Power Quality Semester / Branch / Section : II‐Power Systems Engineering‐ UNIT – I ‐ INTRODUCTION PART – A 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. What is power quality? What is the most common power quality problem? How can power quality problem be detected? What are Harmonics? How do measure/characterize power quality? Differentiate between power quality, voltage quality & current quality? What are the various power quality issues? What is the meaning of power quality disturbances? Define long duration variations and short duration variations and classify it events? What are the causes of Sags? What are the causes of Swells & Interruption? Define wave form distortions and what are the components? Define Total Harmonic Distortion and mention the formula used to calculate THD? Define Total Demand Distortion(TDD)? Define (i) DC offset (ii) Inter harmonics (iii) Voltage flicker Differentiate between under voltage and over voltage and what are it causes? Differentiate between Impulsive transients and oscillatory transients and its types? Define voltage unbalance? What are source of voltage unbalance? Define CBEMA curve & ITIC curve? What are the main objectives of power quality standards? PART – B Define power quality? Explain the reasons for increased concern in power quality? (16) What are the majorpower quality issues? Explain them? (16) Explain the characterization of electrical power quality? (16) Write the various IEEE and IEC power quality standards? (8) Discuss about the CBEMA curves. Explain about the event described in the curve? (8) Explain 1) Short duration voltage variation (8) 2) Long duration voltage variation (8) 7. Explain 1) Transients 2) Wave form distortion (16) 8. Explain the power quality Phenomena or disturbances? (16) 9. Explain in detail about power quality problem? (16) 10. Explain power quality standards? (8) 1. 2. 3. 4. 5. 6. UNIT II www.Vidyarthiplus.com 5. 16.Vidyarthiplus. 6. 5. 9. What is a complex power? What is a displacement factor or fundamental power factor? What is a distortion factor? What is a three phase instantaneous active power? What is a three phase instantaneous reactive power? What is a sequence component? What is positive sequence power and unbalance power? What is a Budeanu’s reactive power? What is a Voltage regulation? Write instantaneous symmetrical components? Compare three phase three wire system with three phase four wire system. 17. 7. 7. Explain in detail about Non‐sinusoidal voltage source supplying Non‐linear load current. 11. reactive and apparent power? Write a voltage expression for balanced three phase system.www. 3. 15. Explain in detail about sinusoidal voltage source supplying Non‐linear load current. Part A What are linear and non‐linear loads? What is an instantaneous voltage. Explain in detail about three sinusoidal balanced systems. Explain three phase four wire system. 3. Explain in detail about three Non‐sinusoidal balanced systems. UNIT – III www. 4. Explain the concept of Power Factor. 18.Vidyarthiplus. 6. 4.com ANALYSIS OF SINGLE PHASE AND THREE PHASE SYSTEM 1. Explain in detail about Non‐sinusoidal voltage source supplying linear load current. 8. current and Power? What is an active. 13. Explain in detail about sinusoidal voltage source supplying linear load current. 10. Part B 1. Give the short notes on voltage regulation and distortion factor. 8. 2. 10. 2. 14. 19. 20. 9.com . 12. Write a voltage expression for unbalanced three phase system. Explain three phase three wire system. What is meant three phase three wire system? What is meant by three phase four wire system? What is power factor? Name any four types sag mitigation devices. Write short notes on phasor symmetrical component quantities. 18.com . Explain Load compensation. PART – A What is load compensation? What is voltage regulation? What is DSTATCOM? How using DSTATCOM in load compensation? Define ideal shunt compensator? What is PCC (Point of Common Coupling)? What is property of ideal shunt compensator? What is open loop balancing? What is closed loop balancing? What is current balancing? Define Bus admittance and Bus susceptance? Define Zero. 3. 17. 5. 3. 6. 10.www. 10. 5. 4. 7. 4. Brief notes on harmonic reduction and depth of the voltage dip. 2. Explain Voltage regulation with necessary diagram. Line to line voltage response? Define the Harmonic Reduction? Define voltage sag (or) dip reduction? What is depth of the voltage dip? What is Instantaneous symmetrical component? What is symmetrical components operator? Write the transformation matrix (P) of symmetrical components? Write an instantaneous real & reactive power matrix for three phases instantaneous? PART – B 1.Vidyarthiplus. 2. 20. 19. 16.Vidyarthiplus. 8. 14. Explain in detail about classical load balancing problem? Explain in detail about harmonic reduction with example? Explain in detail about voltage sag (Or) dip reduction with example? Derive the symmetrical components of phasor quantities? Derive the instantaneous real and reactive power components? Derive the expression for extraction of fundamental sequence components from measured quantity? 9. 11. 15. 6. Positive and Negative phase sequence? Write matrix of equation of phase voltage response. 13. www. 9. 8. 12. 7.com CONVENTIONAL LOAD COMPENSATION METHODS 1. 10) Explain in detail about ideal three phase shunt compensator structure. what happen.com Unit IV LOAD COMPENSATION USING DSTATCOM 1) 2) 3) 4) 5) 6) 7) 8) 9) 10) 11) 12) 13) 14) 15) 16) 17) 18) 19) 20) Part A What are the primary aims of a shunt compensator in a distribution system? Define the factor . when both load and source are unbalanced? In DSTATCOM current control through phasors. If voltage source is balanced & loads are unbalanced then thevenin equivalent voltage source gets balanced or unbalanced? Justify your answer and what is the effect? In DSTATCOM current control through phasors. 4) Explain DSTATCOM Structure 5) Explain control of DSTATCOM connected to stiff source 6) Explain DSTATCOM connected to a Weak supply point 7) Explain switching control of DSTATCOM. Part B 1) Explain in detail about compensating single –phase load. when both load and source are unbalanced as well as disorted? What are the modes exhibits in voltage control mode? Show the result when compensator is connected at the end of the 1st cycle What is PQ theory? Write the power invariant transformation. 8) Explain DSTATCOM in voltage control mode 9) Show the results when compensator is connected at the end of the 1st cycle and explain the effects in detail. What happens.Vidyarthiplus. 2) Explain in detail about generating reference current using instantaneous PQ theory. Draw the DSTATCOM structure with neutral clamped three phase VSI. www. when both load and source are unbalanced and load is disorted? In DSTATCOM current control through phasors.com . what happen. what happen.Vidyarthiplus. if the transformers are connected in H‐bridge VSI in the DSTATCOM structure? How the chopper circuit in DSTATCOM structure can be equals the voltage across the capacitor (Cdc)? Is chopper circuit can compensate the zero sequence current? How? What is the drawback of connecting transformer in DSTATCOM structure? What is the purpose of including transformers in DSTATCOM structure? How can we eliminate the distortion in source current? What is switching control of DSTATCOM? What is switching band tracking control? Write the function used in switching control.www. 3) Explain in detail about generating reference currents using instantaneous symmetrical components. 9. Give the short notes on series and shunt compensation. 11. Describe DVR Structure. 9. Part A What is DVR? Draw the DVR Structure What is UPQC? What are the UPQC configurations? Draw the right shunt UPQC configuration? Draw the left shunt UPQC configuration? What is the basic principle of series compensation? Difference between shunt and series compensation? How the harmonics in non‐linear loads can be neutralized? What is the drawback of DVR structure? What is series active filter? Compare and Contrast between DVR and DSTATCOM structure. 8. 13. 10. 3.Vidyarthiplus.www. Compare and Contrast between DVR and DSTATCOM structure. 8. 17. 7. 6. 20. Explain about DC capacitor Supported DVR. What is voltage restoration? What is dc capacitor supported DVR? What is the Rectifier supported DVR? What is DVR structure? What are the advantages of series active filter? Write the state equation of left shunt UPQC Control. 18. 2. What is mean by series active filter? Part B 1. 3. 5. 4.Vidyarthiplus. What is UPQC?Explain the UPQC Configurations Explain Structure & Control of Right Shunt UPQC. 5. 4. 19. 10. Explain Series Active Filter.com . 2. 7. Derive the State Equation of left Shunt UPQC Control. www. Give the example of voltage restoration. Describe about rectifier supported DVR with Example. 16. 12.com UNIT‐5 SERIES COMPENSATION OF POWER DISTRIBUTION SYSTEM 1. 6. 15. 14. Describe about voltage Restoration with Example.