Power Systems and Restructuring

Nouredine Hadjsaïd, Jean-Claude Sabonnadière

• Publisher: Wiley-ISTE
• Year: 2013
• ISBN:
  9781118599921
• Edition: 1
• Topic: Tecnologia e ingegneria
• Subtopic: Risorse energetiche

The development of electric power systems has been made up of incremental innovations from the end of the 19th century and throughout the 20th century. The creation of deregulated electricity markets has brought about an emerging paradigm in which the relationships between producers, power system operators and consumers have changed enormously compared to the monopolistic case.

The scope of this book is to provide fundamental concepts of the physics and operation of transmission and distribution lines, which is the content of Part 1, followed by the models and tools for the description and simulation of large electrical grids for steady state and transient operation. These advanced tools allow the physics and technology of power systems to be described and the algorithms of Ybus and Zbus matrices to be built for various studies such as short-circuit studies and load flow or transient phenomena analysis.

Part 3 deals with the new organization concepts in the frame of deregulated markets. In this part the restructuring of the power industry is presented where various actors interact together through market places or bilateral contracts. In addition, the operation of the power grids under this deregulated context is detailed and the relationships between power system operators and market actors (energy producers and providers, traders, etc.) is explained with several examples. The ancillary services, congestion management and grid access concepts are also described.

A large number of exercises and problems disseminated throughout the book with solutions at the end enable the reader to check his understanding of the content at any time.

PART 1

TRANSMISSION LINES AND ELECTRIC POWER NETWORKS

Chapter 1

The Two Paradigms of the World Electrical Power System

The term ‘electrical system’ is used to define the entire chain of electricity supply from the most distant generation centers to the load centers, while including electrical transmission and distribution systems. The distinction between electric transmission and distribution will be approached in later chapters. This system is the basis of the electric energy supply on which modern economies are strongly dependent. The paradigms governing this system, at the present time, rest on the following:

– the historical paradigm based on a vertical organization within the framework of integrated monopolistic operation, centralized production and electrical networks;

– the liberalization of energy markets within a competing framework.

1.1. Introduction

Before describing in detail the operation of lines and elements that constitute the transmission or distribution network, it is important for us to indicate to our readers very important changes that have occurred in the electric systems by worldwide evolution of legislation relating to the management of energy networks at the end of the 20th century. This change, known as liberalization of the energy markets, started in certain countries as early as 1980, following the example of Chile and the United Kingdom. The form of liberalization adopted then related mainly to the electrical energy generation sector. Thereafter, liberalization of the energy markets was adopted almost simultaneously in the United States, Europe and in other countries like Australia at the beginning of 1990.

For the United States, it is the National Energy Act of 1992 which truly launched the opening of the energy markets. In Europe, this opening was officially launched in the European Union by Directive 96/92/CE published on December 19, 1996. This document deals with the common rules for the internal electricity market, with an obligation for each country to transpose this directive in its national legislative system, which France did in February 2000 in the form of a law. It is interesting to note that this law founded a minimum opening level of 25% of the market of each Member State. Each state is free to proceed in fully opening its market if it so wishes. This opening was often progressive and was characterized by the concept of eligible consumers. This eligibility is related to the level of consumption.

For countries that initiated by opening 25% of the market, eligible consumers are 25% of the large-scale consumers. A threshold is thus fixed for each market share. Today, this movement of liberalization extends to the entire industrialized world and will undoubtedly soon spread to all electricity companies worldwide. Of course, this opening has had considerable consequences on exploitation, and to a lesser extent system planning. Part 3 of this book will be entirely devoted to economic effects, the effects on technical operation and evolution of management styles of transportation and distribution grids in the context of a liberalized energy market.

We, however, will consider in this first chapter the technical and economic factors that led to the construction of the electric systems on which the supply of electrical energy to private individuals and to companies is based. It is this model that we call the historical paradigm of the development of the electrical energy networks, a paradigm which is to be replaced in a way by that emerging from the liberalization of energy markets. Nevertheless, this model was created more than one century ago on scientific and technical bases, which remain valid in spite of the upheavals induced by the new economic deal. Indeed, the physical laws governing this system remain unaffected by the changing paradigms of exploitation of the system.

1.2. The historical paradigm

1.2.1. Grouped generation: scale effect

The basis of historical development of the networks and, more generally, of electrical systems of generation, transmission, distribution and energy utilization, lies mainly on two very important facts: the impact of electric generator size on the value of output; and the impact of the increase in operating voltage on losses by Joule effect in the cables. Indeed, Joule losses in the transmission of electric power are inversely proportional to the square of the volta...