Environmental Engineering Reference
In-Depth Information
Appendix: Basic Electric Power
Engineering Concepts
A.1 Introduction
This appendix covers some of the very basic topics that underlie the generation, transmission
and use of electrical energy, but it is not intended to be a substitute for a good textbook on
basic electrical engineering. For readers who have no background whatsoever in this topic a
selective study of relevant chapters in a typical good textbook, as, for example, Reference
[1], would be essential.
This appendix is intended for readers who have studied 'electricity' as a subsidiary subject
at university and need to refresh their memories. It is likely that the 'electricity' they have
met was slanted towards the understanding of electronic circuits and devices. This is because
the major concern of electrical engineering since the invention of the transistor and of the
computer has been the 'communications' and 'control' rather than the 'energy' aspects of the
discipline. It is therefore possible that, although such readers are knowledgeable in some
aspects of electricity, they are unfamiliar with the ideas and conventions developed over the
years by power system engineers. If this is the case, they are likely to fi nd this appendix
useful.
For a power system to be an effi cient channel of energy fl ow from generators to consumers
the task should be accomplished with the minimum energy loss. Because of the need to supply
a constant voltage, it is also necessary that the desirable energy transfers are achieved within
specifi ed upper and lower voltage limits at the system junctions or nodes. These requirements
have led to certain analytical concepts that are particular to power systems engineering.
A.2 Generators and Consumers of Energy
A start is made with the defi nition of the conventions used when power is to be calculated
in electric circuits. In Figure A.1 the box represents any single piece or collection of
