Electric Energy

An Introduction, Third Edition

Mohamed A. El-Sharkawi

• Publisher: CRC Press
• Year: 2012
• ISBN:
  9781498760034
• Edition: 3
• Topic: Physical Sciences
• Subtopic: Energy

The search for renewable energy and smart grids, the societal impact of blackouts, and the environmental impact of generating electricity, along with the new ABET criteria, continue to drive a renewed interest in electric energy as a core subject. Keeping pace with these changes, Electric Energy: An Introduction, Third Edition restructures the trad

Chapter 1

History of Power Systems

A large number of great scientists created wonderful innovations that led to the electric power systems as we know them today. Although electricity was discovered around 600 BC, it was not until the end of the nineteenth century that we could have electric energy on demand by flipping a switch at every home, school, office, or factory. Today, dependence on electric power is so entrenched in our societies that we cannot imagine our life without electricity. We indeed take electricity for granted, so when we experience an outage, we realize how our life is dependent on electricity. This dependency creates a formidable challenge to engineers to make the power system the most reliable and efficient complex system ever built by man.

The road to creating an electric power system began when the Greek philosopher Thales of Miletus discussed electric charge around 600 BC. The Greeks observed that when rubbing fur on amber, an electric charge would build up on the amber. The charge would allow the amber to attract light objects such as hair. However, the first scientific study of the electric and magnetic phenomena was done by the English physician William Gilbert (1544–1603). He was the first to use the term electric, which is derived from the Greek word for amber (ηλεκτρον). The word amber itself was derived from the Arabic word Anbar. Indeed, several volumes are needed to justifiably credit the geniuses behind the creation of our marvelous power system. Unfortunately, because of the lack of space, we shall only highlight the milestone developments.

A good beginning point in history would be the middle of the eighteenth century when the Italian scientist, Alessandro Guiseppe Antonio Anastasio Volta (1745–1827), showed that galvanism occurred whenever a moist substance was placed between two different metals. This discovery eventually led to the first battery in 1800. Figure 1.1 shows a model of Volta’s battery that is displayed in the U.S. Smithsonian Museum in Washington, DC. The battery was the source of energy used in subsequent developments to create magnetic fields and electric currents. Today we use the unit volt for electric potential in honor of this great Italian inventor.

Figure 1.1

Model of Volta’s battery. (Courtesy of the Smithsonian Museum, Washington, DC.)

When the Danish Professor Hans Christian Oersted (1777–1851) was working on an experiment that involved the use of battery, he noticed that a compass needle had deflected from its normal heading of the magnetic north. This was the first reported discovery of electromagnetic force created by electric current. This discovery is the basis for the design of electromechanical devices such as motors and actuators. This important relationship between electricity and magnetism was not interpreted by Oersted, but was later explained by André-Marie Ampère. In honor of Oersted, his name is used as a unit for the magnetic field intensity in the centimeter–gram–second (CGS) system.

The next scientist is the French mathematician and physicist André-Marie Ampère (1775–1836). He was the first to explain the ambiguous link between magnetism and electric currents that Oersted could not rationalize. His work is known as Ampere’s law, which relates the magnetic field to electric current. Ampere’s law eventually led to the development of electromagnetic devices such as motors, generators, and transformers. Today we use ampere as the unit of electric current in honor of this French scientist.

The German scientist Georg Simon Ohm (1789–1854) was the first to discover electrical resistance. He noticed that the current passing through a wire increased when the cross section of the wire increase...