IEEE Power & Energy Society

Book Review

Wind Energy

Book Focuses on Power Quality

The book title is wind energy, but according to the reviewer, the focus is really on power quality and energy storage. The reviewer suggests a title that might be more appropriate: Applications of Energy Storage on Weak Power Systems with Fixed-Speed Wind Turbines.

Wind Energy Systems—Solutions for Power Quality and Stabilization

By Mohd. Hasan Ali, ISBN 9781439856147

This book, which was published in 2012, provides an overview of the wind energy conversion process and elements of power systems, electric machines, and power electronics. The book is rooted in academic experience and literature and is somewhat isolated from the mainstream applications of wind turbines and wind power plants around the world today.

Chapter 1 contains a brief introduction to the global status of wind energy as of 2008. The chapter could have benefitted from an update before it was published in 2012.

Chapter 2 provides a good introduction to the basics of the wind energy conversion process for the constant speed machine, which lost its dominant market share by 2005. The bulk of the references are from 2005 and earlier.

In Chapter 3, there is a good overview of the basic elements of electric power systems and electric machines and a brief introduction to the topics of power quality and transient overvoltages. As the longest chapter in the book, its emphasis seems somewhat misplaced.

Chapter 4 provides a good overview on power electronic devices and circuits.

Chapter 5 is a brief introduction to fixed- and variable-speed wind energy conversion systems and goes on to illustrate wind generator efficiency calculations in great detail. The chapter has few references after 2006.

Chapter 6 provides a superficial look at grid integration issues, mentioning transient stability and power quality, output variability, grid code requirements, power system design and operation, energy storage, transmission infrastructure, and system adequacy. With the exception of grid codes, a mention is about all they get.

In Chapter 7, we now get to the heart of the book, power quality issues on isolated power systems dominated by diesel generation with some fixed-speed wind turbines and how energy storage systems can provide solutions. The major discussion is focused on superconducting magnetic energy storage. Examples using flywheels, supercapacitors, and pitch control are also provided.

Chapter 8 continues the theme, covering transient stability problems in systems with a large penetration of fixed-speed wind turbines and expands the range of solutions to include the STATCOM, braking resistor, and the superconducting fault current limiter.

Chapter 9 concludes the book with an overview of the fault ride-through capability of variable speed machines, with a focus on converter control for reactive support.

The title of the book is misleading at best. The main focus of the book is on power quality and energy storage, using small power systems with a high penetration of fixed-speed wind turbines as a vehicle to illustrate potential solutions to hypothetical problems. A serious shortcoming of the book is the reliance of the author on primarily academic research and papers. The book could benefit from a heavy dose of reality from the real world of power system design and operation with modern wind turbines and wind power plants. I also find the constant use of the term “windmill” to refer to a wind turbine to be annoying. A windmill is a device to grind grain or pump water; a wind turbine is a device to produce electricity.

Many of the results of current wind integration work are contained in the published reports of studies that don’t always end up in conference papers or proceedings. I saw precious few references to such work in the chapter references. The assimilation and inclusion of such work in the book would provide a much firmer grounding and greater relevance for the work. I was particularly surprised at the focus on energy storage in Chapter 7, after reading in Chapter 6 of the recognition that energy storage is not a cost-effective option for wind integration in most situations. The level of detail in Chapter 7 is simply out of proportion with the remainder of the book.

Regarding the transient stability issues in Chapter 8, no one today would build a power system with a high penetration of fixed-speed induction machine wind plants. While the book leaves the reader with the impression that a power system with wind plants needs to be stabilized with energy storage or related devices, in fact modern wind turbines can help stabilize power systems! It is unfortunate that the author chose outdated wind turbine technology as the vehicle to illustrate energy storage solutions to power system problems. A better title for the book might have been Applications of Energy Storage on Weak Power Systems with Fixed Speed Wind Turbines.

The book provides neither the information required by someone interested in wind turbine design nor in the real-world applications to power systems. It is adequate in some respects in that it does introduce some useful fundamental concepts, but it is misleading in other respects in that it leaves the reader with the mistaken impression that fixed-speed induction machines are the dominant machine in use for wind turbines today and that as a result many mitigation measures are required to secure adequate system performance. In reality, the doubly fed asynchronous generator has the dominant market share currently and can be controlled to provide the broad range of system services required for stable system operation.

—J. Charles Smith

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