Page 7 - Power Electronic Control in Electrical Systems

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Preface

Although the basic concepts of reactive power control in power systems remain
unchanged, state-of-the-art developments associated with power electronics equip-
ment are dictating new ways in which such control may be achieved not only in high-
voltage transmission systems but also in low-voltage distribution systems. The book
addresses, therefore, not only the fundamental concepts associated with the topic of
reactive power control but also presents the latest equipment and devices together
with new application areas and associated computer-assisted studies.
The book offers a solid theoretical foundation for the electronic control of active
and reactive power. The material gives an overview of the composition of electrical
power networks; a basic description of the most popular power systems studies and
indicates, within the context of the power system, where the Flexible Alternating
Current Transmission Systems (FACTS) and Custom Power equipment belong.
FACTS relies on state-of-the-art power electronic devices and methods applied on
the high-voltage side of the power network to make it electronically controllable.
From the operational point of view, it is concerned with the ability to control the
path of power flows throughout the network in an adaptive fashion. This equipment
has the ability to control the line impedance and the nodal voltage magnitudes and
angles at both the sending and receiving ends of key transmission corridors while
enhancing the security of the system.
Custom Power focuses on low-voltage distribution systems. This technology is a
response to reports of poor power quality and reliability of supply to factories, offices
and homes. Today's automated equipment and production lines require reliable and
high quality power, and cannot tolerate voltage sags, swells, harmonic distortions,
impulses or interruptions.
Chapter 1 gives an overview of electrical power networks. The main plant compo-
nents of the power network are described, together with the new generation of power
network controllers, which use state-of-the-art power electronics technology to give
the power network utmost operational flexibility and an almost instantaneous speed
of response. The chapter also describes the main computer assisted studies used by
power systems engineers in the planning, management and operation of the network.
Chapter 2 provides a broad review of the basic theoretical principles of
power engineering, with relevant examples of AC circuit analysis, per-unit systems,
three-phase systems, transformer connections, power measurement and other topics.
It covers the basic precepts of power and frequency control, voltage control and load
balancing, and provides a basic understanding of the reactive compensation of loads.