Application of Flexible AC Transmission System Devices in Wind Energy Conversion Systems

Ahmed Abu-Siada, M.S. Masoum, Yasser Alharbi

• Publisher: Bentham Science Publishers
• Year: 2017
• Print ISBN:
  9781681085432
• eBook ISBN:
  9781681085425
• Topic: Physical Sciences
• Subtopic: Energy

This book presents information about the application of various flexible AC transmission system devices to wind energy conversion systems. Devices such as unified power flow controllers, superconducting magnetic energy storage and static synchronous compensators are covered in this book. Chapters detail features of the topology and basic control systems of each device. Additionally, case studies are presented where necessary to demonstrate practical applications.
This book is a reference for students and technicians studying wind power and AC transmission systems in advanced engineering courses.

Distribution Static Compensators and their Applications in Microgrids

Abu-Siada et al.^*

Electrical and Computer Engineering Department Curtin University, Australia

Abstract

Microgrids are clusters of distributed energy resources, energy storage systems and loads which are capable of operating in grid-connected as well as in off-grid modes. In the off-grid mode, the energy resources supply the demand while maintaining the voltage and frequency within acceptable limits whereas in the grid-connected mode, the energy resources supply the maximum or nominal power and the network voltage and frequency is maintained by the grid. This chapter first summarizes the structure and control principles of microgrids. It then briefly introduces the structures and control perspectives of distribution static compensators (DSTATCOMs). Finally, some applications of DSTATCOMs are discussed in microgrids. The introduced applications are power quality improvement due to the presence of nonlinear and unbalanced loads, voltage regulation and balancing, and interphase power circulation in the case of the presence of single-phase energy resources with unequal distribution amongst phases. Each application is illustrated by examples, realized in PSCAD/EMTDC.

Keywords: Distribution static compensator (DSTATCOM), Interphase power circulation, Load compensation, Microgrid, Voltage regulation.

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^* Corresponding author Farhad Shahnia: Electrical Engineering Department, Murdoch University, Australia; Tel/Fax: ??????????????; Email: [email protected]

INTRODUCTION

The growing electricity demand, the necessity of electricity generation-related costs and emissions, on top of the necessity for improving the reliability of electrical systems and reducing its losses, are driving the electricity utilities around the world towards the utilization of distributed energy resources (DER) within distribution networks and their installation at close distances to the consumption centers [1].

With the introduction of DERs installation in distribution networks and at proximity of loads, the concept of microgrids has been introduced. Microgrids are systems with clusters of DERs, energy storage systems, and loads [2]. Fig. (4.1) illustrates schematically a microgrid system. To deliver power with high quality and reliability, the microgrid should appear as a controllable system that responds punctually to the demand and/or generation changes. Microgrids can operate in a

grid-connected mode as well as in off-grid (also known as islanded or autonomous) mode. The off-grid mode of operation can be during network maintenance (a planned islanding of the microgrid) or during faults in the network (an unplanned islanding). However, some microgrids, especially those in remote areas, usually referred to as standalone microgrids, operate in off-grid mode permanently. Smaller microgrids, also referred to as nanogrids, are also thought to be the principle of future power supply systems to residential customers [3]. In grid-connected mode, the grid dictates the voltage and frequency of the microgrid and the DERs within the microgrid operate at their nominal capacities (for dispatchable ones) or based on their maximum power point tracking (for renewable energy-based non-dispatchable ones). Thus, the DERs are usually controlled under a constant PQ control strategy in this mode of operation. However, in the off-grid mode, one or a group of the DERs control the voltage and frequency, in addition to sharing the load demand. Different control techniques can be used for the operation of DERs in this mode of operation. Some of them can be simple and decentralized (without a need for any communication system) while some can be more complex and Comprehensive to yield optimal results (if proper data communication systems are in place) [4]. Voltage and frequency droop control is one of the simplest while effective decentralized techniques for the control of DERs [5]. Also, droop control can result in power sharing among multiple DERs in the microgrid similar to the power sharing among synchronous generators in traditional power systems. Voltage and angle droop can also be used instead of the voltage and frequency droop [6, 7]....

Table of contents

• Welcome
• Table of Contents
• Title Page
• BENTHAM SCIENCE PUBLISHERS LTD.
• PREFACE
• List of Contributors
• Overview of Wind Energy Conversion Systems and Flexible AC Transmission Systems
• Applications of Unified Power Flow Controller in Wind Energy Conversion System
• Superconducting Magnetic Energy Storage, a Promising FACTS Device for Wind Energy Conversion Systems
• Distribution Static Compensators and their Applications in Microgrids