PART-A 1. What do you mean by voltage sag and voltage swell? 2. Define power frequency variation. 3. Define DC offset.Mention its sources in power system. 4. What is the need for power quality standards? 5. What are the main functions of DVR? 6. What are the causes of short interruptions? 7. How voltage swell differs from transient? 8. What are the mitigation techniques for voltage sag? 9. List the major power quality issues. 10. Define CBEMA. PART-B Discuss about any four power quality issues,indicating more attention in power system. (i)Explain the solid state transfer switch with the transfer operation. (ii)Draw the CBEMA curve and ITIC curve. Explain the following electrical power quality issues in detail with examples. (i) Harmonics. (ii) Voltage interruption. What are the objectives of power quality standards? Discuss about IEEE and IEC standards used for power quality issues. What is the need of estimating sag performance? Explain the different method of estimating voltage sag performance. (i) Explain the operation of DSTATCOM used for sag mitigation. (ii) Discuss the source of sag and interruption.