Transcriber’s Notes
Small capitals have been transcribed as ALL CAPITALS; text in
italics has been transcribed between underscores, as _text_. The
symbol ∩ is used to represent an upside-down U.
More Transcriber’s Notes may be found at the end of this text.
Published by the
McGraw-Hill Book Company
New York
Successors to the Book Departments of the
McGraw Publishing Company
Hill Publishing Company
Publishers of Books for
Electrical World The Engineering and Mining Journal
The Engineering Record Power and The Engineer
Electric Railway Journal American Machinist
ELECTRIC TRANSMISSION
OF
WATER POWER
_By_
ALTON D. ADAMS, A.M.
MEMBER AMERICAN INSTITUTE OF ELECTRICAL ENGINEERS
NEW YORK
MCGRAW-HILL BOOK CO.
1906
Copyrighted, 1906, by the
McGRAW PUBLISHING COMPANY
NEW YORK
TABLE OF CONTENTS
CHAPTER PAGE
I. WATER-POWER IN ELECTRICAL SUPPLY 1
II. UTILITY OF WATER-POWER IN ELECTRICAL SUPPLY 10
III. COST OF CONDUCTORS FOR ELECTRIC-POWER TRANSMISSION 19
IV. ADVANTAGES OF THE CONTINUOUS AND ALTERNATING CURRENT 31
V. THE PHYSICAL LIMITS OF ELECTRIC-POWER TRANSMISSION 44
VI. DEVELOPMENT OF WATER-POWER FOR ELECTRIC STATIONS 51
VII. THE LOCATION OF ELECTRIC WATER-POWER STATIONS 64
VIII. DESIGN OF ELECTRIC WATER-POWER STATIONS 83
IX. ALTERNATORS FOR ELECTRICAL TRANSMISSION 103
X. TRANSFORMERS IN TRANSMISSION SYSTEMS 122
XI. SWITCHES, FUSES, AND CIRCUIT-BREAKERS 135
XII. REGULATION OF TRANSMITTED POWER 155
XIII. GUARD WIRES AND LIGHTNING ARRESTERS 168
XIV. ELECTRICAL TRANSMISSION UNDER LAND AND WATER 187
XV. MATERIALS FOR LINE CONDUCTORS 200
XVI. VOLTAGE AND LOSSES ON TRANSMISSION LINES 215
XVII. SELECTION OF TRANSMISSION CIRCUITS 233
XVIII. POLE LINES FOR POWER TRANSMISSION 246
XIX. ENTRIES FOR ELECTRIC TRANSMISSION LINES 261
XX. INSULATOR PINS 270
XXI. INSULATORS FOR TRANSMISSION LINES 287
XXII. DESIGN OF INSULATOR PINS FOR TRANSMISSION LINES 298
XXIII. STEEL TOWERS 306
INDEX 327
ELECTRIC TRANSMISSION OF WATER-POWER.
CHAPTER I.
WATER-POWER IN ELECTRICAL SUPPLY.
Electrical supply from transmitted water-power is now distributed in
more than fifty cities of North America. These include Mexico City, with
a population of 402,000; Buffalo and San Francisco, with 352,387 and
342,782 respectively; Montreal, with 266,826, and Los Angeles, St. Paul,
and Minneapolis, with populations that range between 100,000 and 200,000
each. North and south these cities extend from Quebec to Anderson, and
from Seattle to Mexico City. East and west the chain of cities includes
Portland, Springfield, Albany, Buffalo, Hamilton, Toronto, St. Paul,
Butte, Salt Lake City, and San Francisco. To reach these cities the
water-power is electrically transmitted, in many cases dozens, in a
number of cases scores, and in one case more than two hundred miles. In
the East, Canada is the site of the longest transmission, that from
Shawinigan Falls to Montreal, a distance of eighty-five miles.
From Spier Falls to Albany the electric line is forty miles in length.
Hamilton is thirty-seven miles from that point on the Niagara
escarpment, where its electric power is developed. Between St. Paul and
its electric water-power station, on Apple River, the transmission line
is twenty-five miles long. The falls of the Missouri River at Cañon
Ferry are the source of the electrical energy distributed in Butte,
sixty-five miles away. Los Angeles draws electrical energy from a plant
eighty-three miles distant on the Santa Ana River. From Colgate
power-house, on the Yuba, to San Francisco, by way of Mission San José,
the transmission line has a length of 220 miles. Between Electra
generating station in the Sierra Nevada Mountains and San Francisco is
154 miles by the electric line.
[Illustration: FIG. 1.--Spier Falls Transmission Lines.]
These transmissions involve large powers as well as long distances. The
new plant on the Androscoggin is designed to deliver 10,000
horse-power for electrical supply in Lewiston, Me. At Spier Falls, on
the Hudson, whence energy goes to Albany and other cities, the electric
generators will have a capacity of 32,000 horse-power. From the two
water-power stations at Niagara Falls, with their twenty-one electric
generators of 5,000 horse-power each, a total of 105,000, more than
30,000 horse-power is regularly transmitted to Buffalo alone; the
greater part of the capacity being devoted to local industries.
Electrical supply in St. Paul is drawn from a water-power plant of 4,000
and in Minneapolis from a like plant of 7,400 horse-power capacity. The
Cañon Ferry station, on the Missouri, that supplies electrical energy in
both Helena and Butte, has a capacity of 10,000 horse-power. Both
Seattle and Tacoma draw electrical supply from the 8,000 horse-power
plant at Snoqualmie Falls. The Colgate power-house, which develops
energy for San Francisco and a number of smaller places, has electric
generators of 15,000 horse-power aggregate capacity. At the Electra
generating station, where energy is also transmitted to San Francisco
and other cities on the way, the capacity is 13,330 horse-power.
Electrical supply in Los Angeles is drawn from the generating station of
4,000 horse-power, on the Santa Ana River, and from two stations, on
Mill Creek, with an aggregate of 4,600, making a total capacity of not
less than 8,600 horse-power. Five water-power stations, scattered within
a radius of ten miles and with 4,200 horse-power total capacity, are the
source of electrical supply in Mexico City.
The foregoing are simply a part of the more striking illustrations of
that development by which falling water is generating hundreds of
thousands of horse-power for electrical supply to millions of
population. This application of great water powers to the industrial
wants of distant cities is hardly more than a decade old. Ten years ago
Shawinigan Falls was an almost unheard-of point in the wilds of Canada.
Spier Falls was merely a place of scenic interest; the Missouri at Cañon
Ferry was not lighting a lamp or displacing a pound of coal; that
falling water in the Sierra Nevada Mountains should light the streets
and operate electric cars in San Francisco seemed impossible, and that
diversion of Niagara, which seems destined to develop more than a
million horse-power and leave dry the precipices over which the waters
now plunge, had not yet begun. In some few instances where water-power
was located in towns or cities, it has been applied to electrical supply
since the early days of the industry. In the main, however, the supply
of electrical energy from water-power has been made possible only by
long-distance transmission. The extending radius of electrical
transmission for water-powers has formed the greatest incentive to
their development. This development in turn has reacted on the
conditions that limit electrical supply and has materially extended the
field of its application. Transmitted water-power has reduced the rates
for electric service. It may not be easy to prove this reduction by
quoting figures for net rates, because these are not generally
published, but there are other means of reaching the conclusion.
[Illustration: FIG. 2.--Snoqualmie Falls Transmission Lines.]
In the field of illumination electricity competes directly with gas, and
in the field of motive power with coal. During the past decade it is
well known that the price of gas has materially declined and the price
of coal, barring the recent strike period, has certainly not increased.
In spite of these reductions electrical supply from water-power has
displaced both gas and coal in many instances.
Moreover, the expansion of electric water-power systems has been
decidedly greater, as a rule, than that of electrical supply from
steam-driven stations. An example of the fact last stated may be seen in
Portland, Me. In the spring of 1899, a company was formed to transmit
and distribute electrical energy in that city from a water-power about
thirteen miles distant. For some years, prior to and since the date just
named, an extensive electric system with steam-power equipment has
existed in Portland. In spite of this, the system using water-power, on
January 1st, 1903, had a connected load of 352 enclosed arcs and 20,000
incandescent lamps, besides 835 horse-power in motors.
Comparing the expansion of electric water-power systems with those
operated by steam, when located in different cities, Hartford and
Springfield may be taken on the one hand and Fall River and New Bedford
on the other. The use of water-power in electrical supply at Hartford
began in November, 1891, and has since continued to an increasing
extent. Throughout the same period electrical supply in Fall River has
been derived exclusively from steam. In 1890 the population of Hartford
was 53,230, and in 1900 it stood at 79,850, an increase of 50 per cent.
At the beginning of the decade Fall River had a population of 74,398,
and at its close the figures were 104,863, a rise of 40.9 per cent. In
1892 the connected load of the electric supply system at Fall River
included 451 arc and 7,800 incandescent lamps, and motors aggregating
140 horse-power. By 1901 this load had increased to 1,111 arcs, 24,254
incandescent lamps, and 600 horse-power in motors. The electric supply
system at Hartford in 1892 was serving 800 arcs, 2,000 incandescent
lamps, and no motors. After the use of transmitted water-power during
nine years the connected load of the Hartford system had come to include
1,679 arcs, 68,725 incandescent lamps, and 3,476 horse-power of motor
capacity in 1901. At the beginning of the decade Hartford was far
behind Fall River in both incandescent lamps and motors, but at the end
Hartford had nearly three times as many incandescent lamps and nearly
six times as great a capacity in connected motors. As Fall River had a
population in 1900 that was greater by thirty-one per cent. than the
population of Hartford, and the percentage of increase during the decade
was only 9.1 lower in the former city, water-power seems to have been
the most potent factor in the rise of electric loads in the latter.
Electric gains at Hartford could not have been due to the absence of
competition by gas, for the price of gas there in 1901 was $1 per 1,000
cubic feet, while the price in Fall River was $1.10 for an equal amount.
Water-power began to be used in electrical supply at Springfield during
the latter half of 1897. In that year the connected load of the
Springfield electric system included 1,006 arcs, 24,778 incandescent
lamps, and motors with a capacity of 647 horse-power. Five years later,
in 1902, this connected load had risen to 1,399 arc lamps, 45,735
incandescent lamps, and a capacity of 1,025 horse-power in electric
motors. At New Bedford, in 1897, the electric system was supplying 406
arc and 22,122 incandescent lamps besides motors rated at 298
horse-power. This load, in 1902, had changed to 488 arcs, 18,055
incandescent lamps, and 432 horse-power in capacity of electric motors.
From the foregoing figures it appears that while 82 arc lamps were added
in New Bedford, 393 such lamps were added in Springfield. While the
electric load at New Bedford was increased by 134 horse-power of motors,
the like increase at Springfield was 378 horse-power, and while the
former city lost 4,067 from its load of incandescent lamps, the latter
gained 20,957 of these lamps. During all these changes electrical supply
in Springfield has come mostly from water-power, and that in New Bedford
has been the product of steam. Population at Springfield numbered 44,179
in 1890 and 62,059 in 1900, an increase of 40.5 per cent. In the earlier
of these years New Bedford had a population of 40,733, and in the later
62,442, an increase of 53.3 per cent. In 1902 the average price obtained
for gas at Springfield was $1.04 and at New Bedford $1.18 per 1,000
cubic feet.
Springfield contains a prosperous gas system, and the gross income there
from the sale of gas was thirty-one per cent greater in 1902 than in
1897. During this same period of five years the gross income from sales
of electrical energy, developed in large part by water-power, increased
forty-seven per cent. For the five years of general depression, ending
in 1897 gross annual income of gas sales in Springfield rose only five
per cent, and the like electric income nine per cent. In the five years
last named the electrical supply system was operated with coal.
The application of transmitted water-power in electrical supply has
displaced steam as a motive power in many large industrial plants that
never would have been operated from steam-driven electric stations. An
example of this sort exists at Portland, where one of the motors
operated by the electric water-power system, in an industrial plant, has
a capacity of 300 horse-power. Every pound of coal burned in Concord, N.
H., is hauled by the single steam railway system entering that city,
which railway operates large car and repair shops there. Some years ago
the railway installed a complete plant of engines, dynamos, and motors
for electric-driving throughout these shops. These engines and dynamos
now stand idle and the motor equipment, with an aggregate capacity of
590 horse-power, is operated with energy purchased from the local
electrical supply system and drawn from water-power.
Another striking example of the ability of electric water-power systems
to make power rates that are attractive to large manufacturers may be
seen at Manchester, N. H. One of the largest manufacturing plants in
that city purchases energy for the operation of the equivalent of more
than 7,000 incandescent lamps, and of motors rated at 976 horse-power,
from the electrical supply system there, whose generating stations are
driven mainly by water-power. The Manchester electrical supply system
also furnishes energy, through a sub-station of 800-horse-power
capacity, to operate an electric railway connecting Manchester and
Concord. This electric line is owned and operated in common with the
only steam railway system of New Hampshire, so that the only inducement
to purchase energy from the water-power system seems to be one of price.
In Buffalo the electric transmission system from Niagara Falls supplies
large motors of about 20,000 horse-power capacity in manufacturing and
industrial works, and 7,000 horse-power to the street railway system,
besides another 4,000 horse-power for general service in lighting and
small motors. Few large cities in the United States have cheaper coal
than Buffalo, and in Portland, Concord, and Manchester coal prices are
moderate. In the Rocky Mountain region, where coal is more expensive,
the greater part of the loads of some electric water-power systems is
made up of large industrial works. In Salt Lake City the electrical
supply system, which draws its energy almost exclusively from
water-powers, had a connected load of motors aggregating 2,600
horse-power as far back as 1901, and also furnished energy to operate
the local electric railway, and several smelters six miles south of the
city, besides all the local lighting service. As good lump coal sells
in Salt Lake for $4.50 per ton, slack at less than one-half this figure,
and the population there by the late census was only 53,531, the figures
for the load of motors are especially notable. At Helena energy from the
10,000 horse-power station at Cañon Ferry operates the local lighting
and power systems, two smelting and a mining plant.
CITIES WITH ELECTRICAL SUPPLY FROM WATER-POWER.
+------------------+-----------------+--------------+-----------+
| |Miles from Water-|Horse-Power of| |
| City. | Power to City. | Water-Driven |Population.|
| | | Stations. | |
+------------------+-----------------+--------------+-----------+
|Mexico City | 10 to 15 | 4,200 | 402,000 |
|Buffalo | 23 | [A]30,000 | 352,387 |
|Montreal | 85 | -- | 266,826 |
|San Francisco | 147 | 13,330 | 342,782 |
|Minneapolis | 10 | 7,400 | 202,718 |
|St. Paul | 25 | 4,000 | 163,065 |
|Los Angeles | 83 | 8,600 | 102,479 |
|Albany | 40 | 32,000 | 94,151 |
|Portland, Ore. | -- | -- | 90,426 |
|Hartford | 11 | 3,600 | 79,850 |
|Springfield, Mass.| 6 | 3,780 | 62,059 |
|Manchester, N. H. | 13.5 | 5,370 | 59,987 |
|Salt Lake City | 36.5 | 10,000 | 53,531 |
|Portland, Me. | 13 | 2,660 | 50,145 |
|Seattle | -- | 8,000 | 80,671 |
|Butte | 65 | 10,000 | 30,470 |
|Oakland | 142 | 15,000 | 66,900 |
|Lewiston, Me. | 3 | 3,000 | 23,761 |
|Concord, N. H. | 4 | 1,000 | 19,632 |
|Helena, Mont. | 20 | -- | 10,770 |
|Hamilton, Ont. | 35 | 8,000 | |
|Quebec | 7 | 3,000 | |
|Dales, Ore. | 27 | 1,330 | |
+------------------+-----------------+--------------+-----------+
[A] Power received.
In Butte, energy from the station just named operates the works of five
smelting and mining companies, driving motors that range from 1 to 800
horse-power in individual capacity. The capacity of the Butte
sub-station is 7,600 horse-power.
The great electric water power system marked by the Santa Ana station at
one end and the city of Los Angeles at the other, eighty-three miles
distant, includes more than 160 miles of transmission lines, several
hundred miles of distribution circuits, and supplies light and power in
twelve cities and towns. Among the customers of this system are an
electric railway, a number of irrigation plants, and a cement works.
These works contain motors that range from 10 to 200 horse-power each
in capacity. Motors of fifty horse-power or less are used at pumping
stations in the irrigation systems.
Applications of water-power in electrical supply during the past decade
have prepared the way for a much greater movement in this direction.
Work is now under way for the electric transmission of water-power,
either for the first time or in larger amounts, to Albany, Toronto,
Chicago, Duluth, Portland, Oregon, San Francisco, Los Angeles, and
dozens of other cities that might be named.
Another ten years will see the greater part of electrical supply on the
American continent drawn from water-power.
Only the largest city supplied from each water-power is named above.
Thus the same transmission system enters Albany, Troy, Schenectady,
Saratoga, and a number of smaller places.