Introduction to Power Quality

One of the properties of electricity is that some of its characteristics depend not only on the electricity producer/distributor but also on the equipment manufacturers and the customer. The large number of players combined with the use of terminology and definitions which may sometimes be imprecise partly explain why this subject area is so complex.

This "Cahier Technique" aims to facilitate exchanges on this topic between specialists and non-specialists, as well as customers, manufacturers, installers, designers and distributors. The clear terminology used should help avoid confusion. It describes the main phenomena causing degradation in Power Quality (PQ), their origins, the consequences for equipment and the main solutions. It offers a methodology for measuring the PQ in accordance with differing aims. Illustrated with practical examples for the implementation of solutions, it shows that only by observing best practice and by applying strict methodology (diagnostics, research, solutions, implementation and preventive maintenance) can users obtain the right quality of power supply for their requirements.

Contents

1 Introduction

1.1 Context

1.2 Objectives of Power Quality measurement

2 Degradation of PQ: origins – characteristics - definitions

2.1 General

2.2 Voltage dips and interruptions

2.3 Harmonics and inter-harmonics

2.4 Overvoltages

2.5 Voltage variations and fluctuations

2.6 Unbalance

2.7 Summary

3 Effects of disturbance on loads and processes

 3.1 Voltage dips and interruptions

3.2 Harmonics

3.3 Overvoltages

3.4 Voltage variations and fluctuations

3.5 Unbalance

3.6 Summary

4 Level of power quality

4.1 Evaluation methodology

4.2 EMC and planning levels

5 Solutions for improving PQ

5.1 Voltage dips and interruptions

5.2 Harmonics

5.3 Overvoltages

5.4 Voltage fluctuations

5.5 Unbalance

5.6 Summary

6 Case studies

6.1 Hybrid filtering

6.2 Real time reactive compensation

6.3 Protection against lightning

7 Conclusion

Bibliography