File:Interior of Drum Power House 1924.jpg

Identifier: pacificservicema1627paci (find matches)
Title: Pacific service magazine
Year: 1912 (1910s)
Authors: Pacific Gas and Electric Company
Subjects: Pacific Gas and Electric Company Electric utilities Electrical engineering Public utilities
Publisher: San Francisco : Pacific Gas and Electric Company
Contributing Library: San Francisco Public Library
Digitizing Sponsor: San Francisco Public Library

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fuel burning plants. Present Status At the present time it may be said thattransmission practice is fairly well stand-ardized for voltages up to and including150 kv. Thus far the only 220 kv. systemsin operation are two in California. Oneother is now being built in Pennsylvania.This last step forward in transmission volt-age has attracted so much attention andholds such possibilities for the future thata consideration of its problems and possi-bilities will be of interest. To give these considerations a practicalaspect, reference will be made to the PitRiver Project for illustrations of the pointat issue. Economic Considerations The fundamental reason for the rapidincrease in transmission is to increase thepossible distance of transmission for a givencost or for a given distance to increase thecapacity or lessen the cost. Let us suppose a possible power supplycapable of developing power at a low cost200 to 300 miles distant from a market andlet it be assumed that the probable cost of
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Interior of Drum Power House, a typical high head development with impulse water wheels, operating under a head of 1375 feet. 288 Pacific Service Magazine transmission will permitit being delivered to themarket at a cost that willcompare favorably withthe cost of power fromother sources. Whatpractical problems facethe transmission engineerand what possibilitiesexist. Theory and experienceshow that the capacity ofan alternating current cir-cuit of a given length in-creases with the square ofthe voltage employed,whereas the cost of thecircuit increases only aboutas the first power of itsvoltage. The higher thevoltage that may be em-ployed, the less will be thecost of transmission, provided there is a suf-ficient load for the circuit. For example, a 110 kv. 60 cycle twincircuit line 200 miles in length can carry30,000 kw. per circuit and will cost about$15,000 per mile. A similar 220 kv. linecan carry 120,000 kw. per circuit and willcost about $30,000 per mile. The capacityof the 220 kv.

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