ing of metal arms and metal pins on transmission lines. The results of the study are not entirely conclusive, clearly indicating the necessity for its continuation.

An effort was also made to prepare the foundation for specifications for transmission lines between 10 kv. and 66 kv., constructed on wood poles. Its completion, however, has not been feasible, because of the diversified opinions expressed by various engineers on construction methods, together with the Committee's recent inability to prepare specifications which would sufficiently conform to the requirements of the revised Safety Code. This work, too, should be followed up by succeeding committees.

The experimental research being conducted under the auspices of the subcommittee on Insulator Research of the Leland Stanford Junior University is in progress, and additional appropriations will be required as the work progresses. During the coming year, it is probable that at least $1000.00 will be necessary. This work is of extreme importance as it means the exploration of a field about which little is definitely known. The special study on features of insulator maintenance were likewise developed to a further extent, supplementing the information published last year.

In regard to the Safety Code, the section covering line construction is the one most unsatisfactory to the industry. There is no doubt but that extensive study will be required in order to accurately determine a practical exposition of the mechanics of pole lines. This study is necessary in order to determine the basis of loading under which line construction should be designed and built. A plan has been proposed by the Safety Rules Committee necessitating certain investigations in the field; and, possibly, some experimental work should be conducted by the Overhead Systems Committee. It is hoped that this can and will be carried on jointly with the Bureau of Standards. An appropriation will undoubtedly be required to cover this work. The amount needed, however, cannot be determined until the extent of the work to be undertaken is finally decided upon. Attention is especially called to the section of the report on preservative treatment of poles and crossarms. Through the co-operation of the American Telephone and Telegraph Company, revised specifications covering such work are made available, the adoption of which, by this Association, will standardize pole preservative practice to such an extent that a large material benefit will accrue to the entire industry. The plan suggested differs from that adopted by the Preservative Committee of the Association in 1910 and 1911, in that the grade of oil has been somewhat lowered, with a corresponding reduction in cost. While these specifications are not intended to entirely supersede the work of the 1910 and 1911 Committee, the Committee suggests that they be at least tentatively adopted while the higher costs prevail.

Important confirmatory information on the result of brush and butt treatment in the plant of the American Telephone and Telegraph Company has

been made available through the courtesy of that Company and the Forest Products Laboratory at Madison, Wisconsin. Special acknowledgment is made in the report of the hearty co-operation and active assistance rendered by the Forest Service and the American Telephone and Telegraph Company. Chapters are also devoted to additional and revised specifications for line material; farm line construction; proposed revision of pole specifications; low voltage lightning arrester installations; transformer maintenance and installations; substitutes for wood poles; live line maintenance devices and methods; and other pertinent subjects.

Prime Movers Committee

During the past year meetings were held at Chicago, Philadelphia, Salt Lake City, New York City, Schenectady and Pittsburgh. The wide distribution of meeting places gave ample opportunity for the entire membership of the Committee to attend some of the meetings. The Salt Lake meeting was the first attempt of the Technical National Section for a meeting of the Eastern and Western men around the table, and the attendance was about equally divided.

The Committee added to its work this year the following new subjects for the Annual Report: 1-Small Steam Prime Movers, 2-Treatment of Feed Water, 3-Station Piping,

4-Burning of Liquid and Gas Fuels,
5-Burning of Waste Fuels.

Another important addition to the work of the Committee is a subcommittee which formulates requests to manufacturers for the development of apparatus which central station men find inadequate. These problems are carefully studied and with the unanimous approval of the Main Committee, a formal request is sent to the manufacturer, asking his co-operation and assistance in developing new or improving existing apparatus.

During the past year considerable progress has been made in developing the probable scope of the operating code and establishing a line of demarcation between the code and the regular annual report of the Committee.

At the October, 1920, meeting the Organization Committee of the operating code reported a tentative plan of procedure, limiting the scope of the code to operation, maintenance and report on the elements entering into the production of electric power by central stations, starting with the fuel with which the power is generated and terminating at the coupling between the prime mover and the generator.

The code will include power generating systems having more than one generating station supplying one or more transmission systems.

Scope of Code

A-Definitions.

B-Organization and Personnel. C-Acceptance of Equipment.

D-Operating Guides. E-Operating Codes. F-Operating Report.

The formulation of equipment codes was assigned to the subcommittees handling these subjects for the regular annual report, and additional subcommittees were appointed for the subjects of Definitions and Organization and Personnel.

This is a continuing work and, as soon as a tentative code for any subject has been developed, it will be presented to the membership for criticism. through the Bulletin and at some later date provision will be made for a general open discussion.

Underground Systems Committee

The Underground Systems Committee, in its report, covers the subjects pertaining to underground transmission and distribution in a more or less general way, treating a number of the subjects altogether from the historical point of view. The Subcommittee on Cable Research, which, last year, prepared the standard specification for paper insulated underground cable, has continued its work of investigation along the lines of cable design and gives in its report this year some valuable information pertaining to characteristics of insulation of underground cables.

Safety Rules Committee

The Safety Rules Committee, prior to last year, was a general committee of the Association, unaffiliated with any section. Its activities, however, have been practically confined to the technical features of the design, construction and operation of plant equipment and, therefore, it has very properly been made a part of the Technical National Section. Practically all of its efforts have been in conjunction with the Bureau of Standards in revising the second edition of the National Electrical Safety Code, published in 1916. The third edition of the code has just been issued, and this Committee is now actively engaged in its study and will report that it is, in general, satisfactory with the exception of that portion covering the strength of overhead lines.

Last year's report reviewed the exhaustive efforts which had been made to satisfactorily decide this important question, and it is unfortunate that a solution which would receive the approval of the entire industry could not be found. It was recommended, however, that the requirements covering the strength of construction as published in the 1916 code should be continued until sufficient data could be collected from which definite recommendations might be made. It being recognized, however, that the securing of this data was a very complex problem, the Bureau of Standards was unwilling to accept this suggestion, and the new edition of the

code, recently issued, contains loading specifications which are considered somewhat more severe than those published in 1916.

The Safety Rules Committee has outlined a plan for attempting to solve this question, which consists, briefly, of studying the relative hazards of various types of construction, separately considering the supports and the conductors. It proposes to carefully determine by experiment or otherwise the proper method of calculating the strength of pole lines and, if necessary, to make a detail study of the loads to which lines are subjected in various sections of the country. This plan has been endorsed by the Overhead Systems Committee and by many leading Transmission Engineers, and has been submitted to the Bureau of Standards for its approval. The Committee has the assurance of Dr. Rosa, representing the Bureau, that it will be given every consideration. Other minor changes may be desirable, and this Committee will continue to co-operate with the Bureau of Standards in attempting to redraft such rules as need revision.

The code was submitted in typewritten form to the American Engineering Standards Committee in November, 1920, for approval as an American. standard. It was withdrawn, however, but will be re-submitted within the next year. It, therefore, is extremely important that it be subjected to a very thorough trial in order that your representative can be informed of any revisions necessary before it is adopted as an American Standard.

The Safety Rules Committee during the past year has constantly recommended that the National Electric Safety Code be adopted by the various public service commissions in preference to any other code, in the hope that eventually the rules regulating the electric light and power industry will be uniform throughout the entire country.

The past two years' service rendered to the Association has been most interesting, because, I feel, that something has been contributed to the good of the Association and the industry. In retiring as Chairman of the Technical National Section I wish to express my appreciation of the loyal and enthusiastic support given me by the Executive Committee, Committee Chairmen and members and to bespeak similar co-operation for my successor.

was

THE PRESIDENT: Mr. Moultrop referred to the Advisory Committee on Engineering that formed at the time of the Pasadena Convention. We are particularly fortunate in having with us Prof. Charles S. Scott, Professor of Electrical Engineering of Yale University, who, in the absence of the Chairman of that Committee, Professor Thomson, will make the report. It gives me great pleasure to present to you Professor Scott.

sents some significant features of the power industry as a whole. Some of the larger engineering problems in the immediate development of the power

industry are considered and the probable trend of this development and some of its limitations are discussed.

Economic and Industrial Growth

"The outstanding feature of world-wide economic and industrial history during the last half-century has been the marvelous growth of industry in the United States. No other country has had such great industrial expansion; no other has had such advance in the standards of living of its people and in the betterment of its cities and home centers; and here the mass of people have comforts which in other countries only wealth commands." (From recent address by Samuel Insull.)

Underlying these developments is the use of power, power in industry and in transportation. It was the steam engine which led to machinery, to great industries, to railway transportation, to commerce and big business, to the building of the Nation..

Electricity for Power

Electricity gives power new meaning and new possibilities. Steam power unaided must be produced in small units and used locally, but electrically transmitted over great areas from enormous stations it permits the greatest diversity in transformation for useful purposes through subdivision and conversion into light and heat and mechanical power.

Just as the steam engine transformed the hand loom into the textile mill and the workbench into the great factory and the stage coach into the express train, and thereby produced new modes of living and a new type of civilization in the nineteenth century, so likewise the electric system is producing far-reaching results by making power universal and doubly effective, and is a new factor in civilization.

Power per capita indicates a nation's social wellbeing; it is a measure of its economic status. Power per worker in the United States is double that in England. The American workman produces more and can be paid more because he uses more power.

Rate of Growth of Electric Power

The population of the United States doubles in about thirty-year periods; the product of our industries doubles in about fifteen-year periods; the output of electric power stations has been doubling in five-year periods. Census reports show the 1917 output to be more than double that of 1912, more than four times that of 1907, more than eight times (in fact more than ten times) that of 1902. During this period the value and kilowatt capacity of the equipment have increased at a slightly less rate.

This remarkable growth, i. e., doubling in five years, or an increase of 15 per cent per annum, has been the approximate rate for thirty years or more.

Our immediate concern is for the future. Is this rate of growth to continue? There are many indications that it will. If it does, there will be required in five years an additional 10,000,000 kw. of station capacity, calling for more than $1,000,000,000 worth of new equipment. Transmission and dis

tribution systems may need as much or more. These general figures show the magnitudes involved in doubling the power supply. The managements of power companies are face to face with vast engineering problems and financial and economic responsibilities. Success or failure involves industrial and economic consequences which affect national progress and prosperity.

Herbert Hoover says that "Engineers should exert themselves in our national engineering policies or the next generation will face a lower instead of a higher standard of living than ours." In the development of transportation, fuel, power, water, in the relief of human toil, in the productivity of machinery in manufacture, in giving the masses of the people comforts and conveniences which ordinarily wealth alone commands, in conserving our resources -in all these no factor of progress is greater than the use of electric power. To the power company industry this need for service is an opportunity, and it is an obligation to promote the new civilization which it is producing.

Scientific and technical knowledge, invention, design, the development of new units into great systems, the application of electricity to a thousand uses in new ways and for new purposes-upon this basis the power system rests. The apparatus and methods of a score of years ago would be inadequate to present service, and those of today will not meet the requirements of the future.

This new service places larger problems and exacting requirements upon the engineer in the production of power and its distribution and effective utilization.

Problems and Progress in Power Production

The immediate problem in producing power is not the discovery of a new method, but the extension of the economical methods now available.

Ever since the alternating current system enabled large power stations and long-distance transmission. to replace small and inefficient stations the trend has been toward the unification of all sources of power so that they may be used in conjunction as in the super-power system. The same kind of interlinking of power plants which now surrounds Chicago and is found in many districts must be continued on a larger and larger scale. This gives to water powers of variable flow a new value, as they can pump power into a great system whenever water is available.

Progress in power plant efficiency is illustrated by the record of the Company in one of our large cities. Coal consumption per kw.-hour has been cut to about a third during the past twenty years. In 1901 it was 6.25 lbs. per kw.-hour; in 1920 it was 2.22, a saving of 4 lbs., or 1.4 cents per kw.-hour with coal at $7 per ton. In other words, if the 1901 economy had not been improved, coal in 1920 would have cost this company $12,000,000 more than it actually cost. Since 1913 the improvement has been one pound, and the resulting saving $3,000,000 in the 1920 coal bill.

Even the 1920 figures represent the joint operation of a number of stations; the newest station was notably better than the average. The power stations of the country are probably operating at an average fuel rate between 3 and 4 pounds, and a conservative figure would be a reduction of 1 pound per kw.-hour if the power were produced by large units. This would mean a fuel saving of $100,000,000 a year with coal at about $5 a ton. Recent coal costs put a new value on power economy.

It does not seem likely that the efficiency of steam turbine generating plants will be greatly improved beyond the results of present best practice.

Little gain in efficiency is to be anticipated from larger sizes. Thermal efficiencies of turbines and of boilers are nearing their theoretical limits. New materials may make practicable higher degrees of steam pressure and higher degrees of superheat. Small improvements are worth while, however, as trivial gains in economy mean many dollars when the output is large.

In order to realize improved performance of machines and of power stations as a whole and of power systems incorporating water and steam plants, high-grade engineering service is essential.

Economic Use of Coal

Reliance will probably, as heretofore, depend in the main on coal resources where water power is not available or is insufficient. But the increasing by-product values, such as tar for road-building, ammonia for fertilizer, benzol as a liquid fuel and also the basis for chemical products, with toluene for dyes and as a source of pheno!, naphthalene, etc., there is a prospect of lessening the cost of fuel by saving the by-products which, in ordinary combustion, are destroyed. Coking ovens have now reached a fair stage of development, as applied in the smelting of iron for example, while gas as a fuel is ideal for many purposes. Waste heat is one of the commonest by-products, and it would seem that in very large scale operations conservation demands that it be turned into power. One may imagine great metallurgic and chemical plants, combined with electric generating stations, supplying surplus power to the proposed super-power networks. By combination of interests in large plants much present expense and loss would be saved. The industries producing heat as a by-product should be associated with those needing it for direct application or needing the power which can be developed from it, any surplus to be sent on to the transmission systems and credited accordingly.

Internal Combustion Engine Mercury Turbine

New sources and methods of developing power lie in the domain of research rather than engineering. It is well recognized in thermo-dynamics that the increased efficiency of conversion of heat energy into mechanical energy largely rests on extending the temperature range upward. The internal combustion engine possesses these advantages. It is limited, however, in the character of its fuel, and the

immediate supply available is inadequate for enabling any considerable part of the power production of the country to be accomplished by this means. A promising new invention employing the same principles of extending the temperature range is the mercury turbine. Even if it were developed to the practical operating stage a serious limitation might be found in the quantity of mercury available or a great increase of cost with increased demand.

Any radically new method of producing power would undoubtedly require an engineering development and the preparation of manufacturing facilities which would prevent it from becoming an important factor in power production for a number of years.

Insulators

The trend for forty years has been toward higher and higher voltage, advancing by stages from 110 and 220 to the 220,000 volts which is in immediate prospect, thereby increasing the radius of economic distribution a thousandfold and the area available for service from a single station a million times.

The fundamental element in transmission is insulation the insulator for overhead lines, the cable for underground circuits.

Market advances are being made in insulator manufacture, both in form and in material.

Cable Manufacture

So much depends on the integrity of a cable for transmission, and such serious consequences follow a breakdown, that there is no need to emphasize the importance of introducing the best methods in cable manufacture. It is probable that most of the breakdowns could be traced to inherent defects, such as the presence of moisture, tending to segregation in spots, imperfect impregnation, and slow deterioration due to high temperatures. When any form of cellulose, such as paper, is used to space the conductors apart there is risk of its not being fully dried, in which case the moisture will tend in prolonged use to transfer itself to the cooler sections and there accumulate. Moreover, cellulose is not at stable substance. At the boiling point of water there is a tendency to a slow charring, with loss of water, and this action seemingly does not cease, but becomes merely unnoticeable at lower temperatures, unless after a great lapse of time. The brownish tint of old books and papers is an evidence of this simple fact. If water is being lost, it must, in a sealed sheath, locate somewhere, and it is well to realize this factor as a serious menace.

More important, however, is the care used in manufacture, in the proper drying of the materials before use, and freedom from exposure to damp air or condensed moisture. In paper-impregnated cables the compound used should be free from moisture or other deleterious constituent, and the impregnation should be equal and thorough throughout the length. In splicing cables in manholes the same need of precaution as to entering moisture should be emphasized. Increase of voltage in cables will become a

necessity of the future in order to increase the load capacity, and must of necessity force consideration of all factors, and especially that of insulation, not merely at the start, but its preservation and continu

ance over years.

Research as to methods of increasing the stability of cellulose, under temperatures above the outside atmosphere, might bring results. This would be work for the organic chemist, who in these days adapts substances to new conditions by substitution of atomic groups by others which confer the needed properties. Celluloid, nitrocellulose, cellulose acetate are examples for special purposes. There is also the suggestion, which is a very old one, of bare conductors with supports or spacers of unchangeable material for supporting them before filling with the insulating composition. Without question improvement in cable construction will for high potential transmission in cities become more and more a dominant factor.

The problems in transmission, including insulators, cables, switches and auxiliary apparatus appliances for meeting emergencies, increase in importance and in difficulty as the voltage and extent of networks and generating capacity increase.

Transmission problems must be worked out under operating conditions; they cannot be wholly solved in laboratory or testing room; hence the power company must study the conditions and formulate the problems, and join with inventor and designing and manufacturing engineers in their solution.

A. C. vs. D. C.

The old-time contention which is summarized in the expression "A. C. vs. D. C." has practically reduced itself to the question whether D. C. distribution should be curtailed or whether it should continue to serve its present areas.

Presumably, the direct current service originally supplied to the central portion of large cities will continue about as it is, owing to the cost of changing customers' appliances. Extensions will be alternating.

The storage battery, once regarded as an essential reserve in the substation, is eliminated. In its stead must be more certain provision for continuity of service in emergency

Many kinds of service for which the D. C. motor was once considered essential are now being satisfactorily performed by alternating motors. There is still the desideratum of an adjustable speed alternating motor.

The maintaining of a high power factor is doubly important when the transmission system is one of high cost, such as is the case in long-distance transmission or with cable distribution.

The method of power factor correction best suited to one case may not apply well to others. In the case of motors, however, either a high inherent power factor or condensers at the motor are fundamentally desirable methods of improving conditions. When three-phase circuits supply large singlephase loads, particularly when the power factor is

low, as in the case of certain electric furnaces, phasebalancing apparatus may be employed. Such apparatus is in highly successful operation in supplying single-phase railways from three-phase generators.

The interlinking of power stations into great systems brings frequency into the foreground. Undoubtedly the trend will be toward a single universal frequency and the method of supplying a second fiequency where this is necessary will require specific consideration and solution.

From Generation and Transmission to Utilization

In the early days how to make a generator was the prime problem before the electrical engineer. Then came problems of transmission and distribution. As these found solution and power became available, the urgent problems extended to the uses of electric power. First, was lighting and the development of lamps; next, mechanical power and the adaptation. of motors to improve methods of production. Then the applications for chemical processes and for electric heating.

Formerly the central station load was a lighting. load, with its huge peaks; then came power load, which raised the valleys in the load curve and finally submerged the lighting. Next comes electric heating with a kilowatt consumption which is astonishing. It is stated that a single brass company in Connecticut could advantageously use in electric heating. more power than all the power stations in the State can produce.

The business of operating open carbon arc lamps gave us the first electric stations. The lamps were applied to street and store lighting and were operated solely on series circuits. The name itself, National Electric Light Association, is a survival from that early period beginning more than forty years ago. The carbon arc light, now largely a thing of the past, will probably survive indefinitely for special uses for which an intense focus of illumination resembling solar light is needed.

But these carbon arcs once so widely used are now replaced by the later developed metallic flame arcs or by large incandescent units. For large area lighting efficiency of light production with the white color of light emitted has tended to the retention of arc lights, as exemplified in the case of many "white way" installations. It is now questionable whether the efficiency of such arcs can be much further improved. At the same time, the color characteristic or whiteness is being more and more approached by the development of incandescents worked at higher temperatures, which possess besides the advantage of greater steadiness and save also the labor expense of electrode replacement, cleaning and general upkeep.

In normal radiation resembling that from a black body high temperatures are necessary to efficiency. In the carbon arc this was the vaporizing point of carbon, or about 4000° C. At such a temperature the light is white, resembling solar light, and is efficiently produced, especially in the large units. In the early days no other artificial light could approach it in these respects.