Grid Integration of Wind Energy

Onshore and Offshore Conversion Systems

Siegfried Heier

• Publisher: Wiley
• Year: 2014
• ISBN:
  9781118703298
• Edition: 3
• Topic: Technology & Engineering
• Subtopic: Power Resources
• Index: Technology & Engineering

This popular reference describes the integration of wind-generated power into electrical power systems and, with the use of advanced control systems, illustrates how wind farms can be made to operate like conventional power plants. Fully revised, the third edition provides up-to-date coverage on new generator developments for wind turbines, recent technical developments in electrical power conversion systems, control design and essential operating conditions. With expanded coverage of offshore technologies, this edition looks at the characteristics and static and dynamic behaviour of offshore wind farms and their connection to the mainland grid.

Brand new material includes:

• comprehensive treatment of onshore and offshore grid integration
• updated legislative guidelines for the design, construction and installation of wind power plants
• the fundamental characteristics and theoretical tools of electrical and mechanical components and their interactions
• new and future types of generators, converters, power electronics and controller designs
• improved use of grid capacities and grid support for fixed- and variable-speed controlled wind power plants
• options for grid control and power reserve provision in wind power plants and wind farms

This resource is an excellent guide for researchers and practitioners involved in the planning, installation and grid integration of wind turbines and power plants. It is also highly beneficial to university students studying wind power technology, renewable energy and power systems, and to practitioners in wind engineering, turbine design and manufacture and electrical power engineering.

Chapter 1
Wind Energy Power Plants

Rising pollution levels and worrying changes in climate, arising in great part from energy-producing processes, demand the reduction of ever-increasing environmentally damaging emissions. The generation of electricity—particularly by the use of renewable resources—offers considerable scope for the reduction of such emissions. In this context, the immense potentials of solar and wind energy, in addition to the worldwide use of hydropower, are of great importance. Their potential is, however, subject to transient processes of nature. Following intensive development work and introductory steps, the conversion systems needed to exploit these power sources are still in the primary phase of large-scale technical application. For example, in Germany around 8% of electricity is already being provided by wind turbines. However in the German provinces Mecklenburg-Western-Pomerania, Schleswig-Holstein, Brandenburg and Saxony-Anhalt there are about 50% wind power feed in. In Germany more power is supplied by wind energy than by hydroelectric plants.

These environmentally friendly technologies in particular require a suitable development period to establish themselves in a marketplace of high technical standards.

The worldwide potential of wind power means that its contribution to electricity production can be of significant proportions. In many countries, the technical potential and—once established—the economically usable potential of wind power far exceeds electricity consumption. Good prospects and economically attractive expectations for the use of wind power are, however, inextricably linked to the incorporation of this weather-dependent power source into existing power supply structures, or the modification of such structures to take account of changed supply conditions.

1.1 Wind Turbine Structures

In the case of hydro, gas or steam, and diesel power stations (among others) the delivery of energy can be regulated and adjusted to match demand by end users (Figure 1.1(a)). In contrast, the conversion system of a wind turbine is subject to external forces (Figure 1.1(b)). The delivery of energy can be affected by changes in wind speed, by machine-dependent factors such as disruption of the airstream around the tower or by load variations on the consumer side in weak grids.

Figure 1.1 Energy delivery and control in electrical supply systems: (a) diesel generators, etc., and (b) wind turbines

The principal components of a modern wind turbine are the tower, the rotor, the nacelle (which accommodates the transmission mechanisms and the generator) and—for horizontal-axis devices—the yaw systems for steering in response to changes in wind direction. Switchgear and protection systems, lines, and maybe also transformers and grids, are required for supplying end users or power storage systems. In response to external influences, a unit for operational control and regulation must adapt the flow of energy in the system to the demands placed upon it. The next two figures show the arrangement of the components in the nacelle and the differences between mechanical–electrical converters in the modern form of wind turbines. Figure 1.2 shows the conventional drive train design in the form of a geared transmission with a high-speed generator. Figure 1.3, by contrast, shows the gearless variant with the generator being driven directly from the turbine. These pictures represent the basis for the functional relationships and considerations of the system.

Figure 1.2 Nacelle of a wind turbine with a gearbox and high-speed 1.5 MW generator (TW 1.5 GE/Tacke). Reproduced by permission of Tacke Windenergie

Figure 1.3 Schematic structure of a gearless wind turbine (Enercon E66, 70 m rotor diameter, 1.8/2 MW nominal output). Reproduced by permission of Enercon

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Table of contents

• Cover
• Title Page
• Copyright
• Preface
• Notation
• Chapter 1: Wind Energy Power Plants
• Chapter 2: Wind Energy Conversion Systems
• Chapter 3: Generating Electrical Energy from Mechanical Energy
• Chapter 4: The Transfer of Electrical Energy to the Supply Grid
• Chapter 5: Control and Supervision of Wind Turbines
• Chapter 6: Using Wind Energy
• Index
• End User License Agreement