In general, we think of an electrical energy system in terms of its most impressive parts: the large generating stations, the transformers, the high voltage lines, etc. If these are some of the basic elements, there are many other components necessary and fascinating. The protection relay is one of them. The role of protection relays in the design and operation of electrical power systems is explained through a brief examination of the general background. There are three aspects of a power system that will serve the purposes of this exam. These aspects are the following:
A. Normal operation
B. Prevention of electrical failures.
C. Mitigation of the effects of electrical outages. The term “normal operation” does not imply team failures, staff errors or “acts of God”. These are the minimum requirements for the supply of existing cargo and a certain amount of expected future cargo. Some of the considerations are:
A. Selection between hydro, steam or other energy sources.
B. Location of the generating stations.
C. Power transmission to the load.
D. Study of the characteristics of the load and planning of its future growth.
E. Measurement
F. Voltage and frequency regulation.
G. System operation.
E. Normal maintenance. The provisions for normal operation imply the greatest expense of equipment and operation, but a system designed to suit this aspect alone could not satisfy current requirements. The faults in the electrical equipment would cause intolerable blackouts