Contents

#### **Preface XI**


Preface

There is an upward trend that human activities involve more electric power nowadays and for years to come. And we will soon be facing shortage of electricity supply if we rely solely on non-renewable power generation from fossil fuels such as coals. Renewable energy generation has proven effective in meeting the demand. At the same time it has brought about a few issues to existing electricity infrastructure such as complex power flow due to distributed generations and unstable grid voltage and/or frequency profiles due to local generation and intermittent nature of renewable energy sources such as solar photovoltaic and wind power. Also the increasing penetration of power electronics converters associated with the adoption of renewable energies into the electricity networks has improved the functionality and flexibility in terms of control but meanwhile due to their switching nature the harmonics issue has to be dealt with. It is therefore important to investigate the causes of these power quality issues and explore feasible and cost-effective solutions to assist with the

In the following chapters the reader will be introduced to power quality issues and solutions at different sections of the electricity networks, namely, power generation, transmission, distribution and end user stages. The book is divided into three sections: Power Quality Issues and Standards in Electricity Networks; Power Quality Improvements in Transmission and Distribution Systems; and Power Quality Improvement in End Users Stage. A brief discussion of each chapter is as follows.

Chapter 1 provides an overview of the causes, impacts, standards and solutions to voltage and current harmonics problems which are one of the key issues related to power quality. Chapter 2 investigates the challenges of increasing wind generation to the network. The chapter has identified and analyzed briefly several key issues including voltage variations, flickers, switching operation of wind generation, current harmonics and locations of wind turbine. Several solutions have been introduced such as low-voltage ride through capability and international standards. Lastly, but not the least, it describes the purposes of grid code to deal with power quality issues with

Flexible Alternating Current Transmission System (FACTS) controllers have been used in transmission and distribution systems to deal with power quality issues. Chapter 3

development of present and future electricity networks.

renewable energy generation.
