Through discovery, invention, and engineering application, the engineer has made electricity of continually greater use to mankind. Electrical power is the driving force to the evolution and improvement of the world.
One of the efforts and means to achieve this goal is to transmit power from the generation source to its “ load” in the most economical and feasible way. This is done via the transmission lines.
Transmission lines are essential for three purposes.
a. To transmit power from a water-power site to a market. These may he very long and justified because of the subsidy aspect connected with the project.
b. For bulk supply of power to load centers from outlying steam stations. These are likely to be relatively short.
c. For interconnection purposes, that is, for transfer of energy from one system to another in case of emergency or in response to diversity in system peaks.
Frequent attempts have been made to set up definitions of “transmission lines, ” “distribution circuits” and “substations.” none has proved entirely satisfactory or universally applicable, but for the purposes of accounting the Federal Power Commission and various state commissions have set up definitions that in essence read:
A transmission system includes all land, conversion structures and equipment at a primary source of supply; lines, switching and conversion stations between a generating or receiving point and the entrance to a distribution center or wholesale point, all lines and equipment whose primary purpose is to augment, integrate or tie together sources of power supply.