Modeling and Analysis with Induction Generators, 3rd Edition

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1

Principles of Alternative

Sources of Energy and

Electric Generation

1.1 SCOPE OF THIS CHAPTER

Induction generators had been used from the beginning of the twentieth century

until they were abandoned and almost disappeared in the 1960s. With the dramatic

increase in petroleum prices in the 1970s, the induction generator returned to the

scene. With the present high energy costs, rational use and conservation implemented

by many processes of heat recovery and other similar forms became important goals.

The end of the 1980s was characterized by a wider distribution of population over the

planet. There were improved transportation and communication systems enabling

people to move away from large urban concentrations. As a consequence, an unprec-

edent growing in power generation caused concerns with the environment leading

many isolated communities to built their own power plants. In the 1990s, ideas such

as distributed generation began to be discussed more intensively in the media and in

research centers. The general consciousness of nite and limited sources of energy

on the earth and international disputes over the environment, global safety, and the

quality of life have created an opportunity for new, more efcient, less polluting

power plants with advanced technologies of control, robustness, and modularity.

In this new millennium, the induction generator, with its lower maintenance

demands and simplied controls, appears to be a good solution for such applications.

For its simplicity, robustness, and small size per generated kilowatt, the induction

generator is favored for small hydro and wind power plants. More recently, with the

widespread use of power electronics, computers, and electronic microcontrollers, it has

become easier to administer the use of these generators and to guarantee their use for

the vast majority of applications where they are more efcient up to around 500 kVA.

The induction generator is always associated with alternative sources of energy.

Particularly for small power plants, it has a great economic appeal. Standing alone,

it usually reaches maximum of 15 kW. On the other hand, if an induction generator

is connected to the grid or to other sources or storage, it can easily approach 100 kW.

Very specialized and custom-made wound-rotor schemes enable even higher power.

More recently, power electronics and microcontroller technologies have given a

decisive boost to induction generators because they enable very advanced and inex-

pensive types of control, new techniques of reactive power supplements, and asyn-

chronous injection of power into the grid, among other features. This chapter will

begin the discussion of these aspects of induction generator technology. The details

will be dealt with in later chapters.