Course Objectives:

1.      To understand the basics and need of power quality indices,

2.      To know about nonlinear and unbalanced loads and their characteristics

3.       To learn about the measurement of electrical quantities and their analysis in frequency and time domain

4.      To impart learning about remedial techniques for improvement in power quality


Introduction: Introduction – Characterization of Electric Power Quality: Transients, short duration and long duration voltage variations, Voltage imbalance, waveform distortion, Voltage fluctuations, Power frequency variation, Power acceptability curves – power quality problems: poor load power factor, Non-linear and unbalanced loads, DC offset in loads, Notching in load voltage, Disturbance in supply voltage – Power quality standards.


Non-Linear Loads: Single phase static and rotating AC/DC converters, three phase static AC/DC converters, Battery chargers, Arc furnaces, Fluorescent lighting, Induction lamp, HID ballast, pulse modulated devices, Adjustable speed drives.


Measurement and Analysis Methods: Voltage, Current, Power and Energy measurements, power factor measurements and definitions, event recorders, Measurement Error – Analysis: Analysis in the periodic steady state, Time domain methods, Frequency domain methods: Laplace’s, Fourier and Hartley transform – The Walsh Transform – Wavelet Transform.


Analysis And Conventional Mitigation Methods: Analysis of power outages, Analysis of unbalance: Symmetrical components of phasor quantities, Instantaneous symmetrical components, Instantaneous real and reactive powers, Analysis of distortion: On–line extraction of fundamental sequence components from measured samples – Harmonic indices – Analysis of voltage sag: Detorit Edison sag score, Voltage sag energy, Voltage Sag Lost Energy Index (VSLEI)- Analysis of voltage flicker, Reduced duration and customer impact of outages, Classical load balancing problem: Open loop balancing, Closed loop balancing, current balancing, Harmonic reduction, Voltage sag reduction.


Power Quality Improvement: Utility-Customer interface – Harmonic filters: passive, Active and hybrid filters –Custom power devices: Network reconfiguring Devices, Load compensation using DSTATCOM, Voltage regulation using DSTATCOM, protecting sensitive loads using DVR, UPQC – control strategies: P-Q theory, Synchronous detection method – Custom power park – Status of application of custom power devices. Difference in role of FACTS devices in transmission and distribution networks.






Course Learning Outcomes (CLO):

On the completion of the course, the student will be able:

1. To understand power quality standards.

2. To identify linear and nonlinear loads.

3. To know about various measurement techniques of voltage and current parameters.

4. To analyse harmonics and their mitigation

5. To acquire knowledge of custom power devices and their role in T&D system.


Recommended Books:

1. Ghosh, A. and Ledwich, G., Power Quality Enhancement using Custom Power Devices, Kluwer Academic Publishers (2002).

2. G.T.Heydt, “Electric Power Quality”, , Stars in a Circle Publications, (1994).

3. C. Sankaran, “Power Quality”, CRC Press, 2002.

4. Derek A. Paice, Power electronic converter harmonics, Prentice Hall Int., 2003