Power supply

“ A pure lighting service tends toward the larger ratio between the average and maximum load, while a larger motor capacity along with the lamps, tends to reduce the ratio. Furthermore, by far the greater part of the energy output of an electrical supply system during each twenty-four hours must be delivered between noon and midnight. ”

“ By generating on a large scale for a wide variety of demands the promoters of the new scheme calculated to be able to offer electrical energy in bulk to electricity supply companies and local authorities at prices substantially below their costs of production at separate stations, and also to provide them and power users with electricity at rates which would compete with other forms of power. ”

“ Even though it goes back and forth in waves of tremendous rapidity, you can see that there must be a time in this period when the electricity is for an infinitesimal space of time at low power, and another infinitesimal space of time at high. In order to keep the supply even and steady, two and sometimes three coils of wire are used in the generator to catch the electricity so that there is scant opportunity for the electric supply to be anything but even, for when one coil is up the other is down and thus they even up the strength of the current. ”

“ The leading factors which make for economy in electricity supply are the magnitude of the output, the load factor, and the diversity factor, also the situation of the power house, the means of distribution, and the provision of suitable, trustworthy and efficient plant. These factors become more favourable the larger the area and the greater and more varied the demand to be supplied. ”

“ Owing to the high relative cost of electric power when generated in small amounts and the great advantages of generating it in proximity to coal mines and waterfalls, the supply of electric power in bulk to small towns and manufacturing districts has become a great feature in modern electrical engineering. ”

“ ACTIVE MODE- The term 'active mode' means the mode of operation when an external power supply is connected to the main electricity supply and the output is connected to a load. ' (C) CLASS A EXTERNAL POWER SUPPLY- ' (i) IN GENERAL- The term 'class A external power supply' means a device that— ' (I) is designed to convert line voltage AC input into lower voltage AC or DC output; ' (II) is able to convert to only 1 AC or DC output voltage at a time; ' (III) is sold with, or intended to be used with, a separate end-use product that constitutes the primary load ”

“ Electric power may move freely through the line up to the line's capacity. Ordinarily, however, the energy generated by each system is sufficient to supply the requirements of the system's customers and no substantial amount of power flows through the interconnection. It is only at the times when one of the connected utilities is unable for some reason to produce sufficient power to meet its customers' needs that the deficiency may be supplied by power that automatically flows through the interconnection from the other utility. ”

“ The most feasible way of obtaining power by electricity to-day seems to be through distribution of the current from a central point of supply; but it is not impossible that a battery may yet be produced which, furnishing electricity as cheaply as a machine, will remove the need of distribution, and at the same time greatly enlarge its field of usefulness. ”

“ If a saving of fuel, measured by the available flow of water during those hours when it can be devoted directly to electrical supply, were its only advantage, the number of cases in which this power could be utilized at a profit would be relatively small. ”

“ Electric light and power are transmitted all over the largest cities. It is no longer necessary that a factory be of any specified size nor that it have any waste power. If it be within reach of the electrical current it may use as much or as little as is needed.
The cheapness of electric power must always depend on nearness to the source of supply or to the market. ”

“ The power station must be able to deal with any exceptional demands which are likely to occur, and consequently more current must be available than is actually required under average conditions. Instead79 of having generating machinery large enough to meet all unusual demands, the generators at a station using continuous current may be only of sufficient size to supply a little more than the average demand, any current beyond this being supplied by a battery of storage cells. ”

“ With the general introduction of electricity for the purpose of lighting comes the introduction of electricity for the production of power; for the same current entering by the same conductors can be used for the production of light or of power, or of both. The same plant at the central stations will supply power by day and light by night, with evident economy. ”

“ The capacity given for generating equipment in each case is that of the main dynamos, where their entire output goes to the transmission line in question, but where the dynamos supply energy for other purposes also, the rating of the transformers that feed only the particular transmission line is given as the capacity of generating equipment. ”

“ In laying out the system great judgment has to be exercised as to the selection of the points of attachment of the feeders to the distributing mains, the object being to keep a constant electric pressure or voltage between the two service-lines in all the houses independently of the varying demand for current. Legally the suppliers are under regulations to keep the supply voltage constant within 4% either way above or below the standard pressure. As a matter of fact very few stations do maintain such good regulation. ”

“ Three main factors are concerned in the cost of electric power transmission, namely, the transformers, the pole line, and the wire or conductors. These factors enter into the cost of transmitted energy in very different degrees, according to the circumstances of each case. The maximum and average rates of energy transmission, the total voltage, the percentage of line loss, and the length of the line mainly determine the relative importance of the transformers, pole line, and conductors in the total cost of delivered energy. ”

“ By means of electricity the work, not only of factories, but also of the home and the farm may be done in any place where electricity can be installed. We must bear in mind that electricity is never a source of power, but is only the agent that carries power to the user. The source of all electric power is either steam or water, produced by water-wheels, turbines, steam-engines or gas-engines. The economical way to furnish electric power is to establish central power plants, and electricity may be conveyed from them for many miles. ”

“ Remember, in estimating the size of your plant for light, heat, and power, that it does not have to be big enough to use all the devices at one time. Also remember, that two water horsepower to one electrical horsepower is a very liberal allowance; and that a generator working under one-half or two-thirds capacity at normal loads will require less attention than a machine constantly being worked above its capacity. Therefore, let your generator be of liberal size, because the difference in cost between a 5 and 10 kilowatt machine is not in proportion to their capacity. ”

“ They state that it has all major refinements, operating on any fuel, producing electricity at any desired voltage up to five million, any chosen cyclic rate from direct current to one thousand megacycles, and any amperage up to one thousand, its maximum power output being fifty kilowatts, limited by the current-carrying capacity of the outputs. ”

“ Since we are going into this work as pioneers, we shall have to be dependent upon our own efforts for the production of the electrical apparatus, so as to be able, with our home-made factory, to provide the power, the heat and the electricity. ”

“ The ideal condition would be when a power station is working at its normal maximum output continuously night and day. This would give a load-factor of 100%, and represents the ultimate ideal towards which the electrical engineer strives by increasing the area of his operations and consequently also the load and the variety of the overlapping demands. It is only by combining a large number of demands which fluctuate at different times—that is by achieving a high diversity factor—that the supplier of electricity can hope to approach the ideal of continuous and steady output. ”

“ If you could store large amounts of electricity in an accumulator of small volume, without appreciable leakage loss, you could build generators designed to handle average rather than peak load—with resultant savings in cost; you could build electric motors, containing their own energy supply and hence portable—which meant electric automobiles and possibly aircraft ”

“ While the maximum investment in transmission conductors may be properly limited in the way just stated, it by no means follows that this maximum limit should be reached in every case. In the varying requirements of actual cases, the problem may be to deliver a fixed amount of power at the least possible cost, or to deliver the largest possible amount of power at a cost per unit under that of development at the point of use. ”

“ As it is a law of every electric circuit that the rate of transformation of electric energy to heat or work in each of its several parts is directly proportional to the drop of voltage therein, it follows that a drop of 500 or 1,000 or 2,000 volts in the conductors of a 10,000-volt transmission line at full load would correspond to a power loss of five to ten or twenty per cent respectively. ”

“ Use of Alternators.—The great increase in the application of electricity for supplying power and for lighting purposes in industry, commerce, and in the home, is due chiefly to the economy of distribution of alternating current. ”

“ We must now consider the question of cost of current, and here we are in many cases up against a difficulty, for unless current can be obtained at a reasonable price the use of electricity in the household is not a paying proposition. Speaking without inside knowledge of the workings of the power companies, it would appear that they are greatly to blame that electricity is not in more general use. ”

“ Concluding, as we do, that the franchise has not expired, but is still subsisting, we come to the question whether it is limited to the distribution of electric current for lighting purposes, or includes its distribution for power and heat. ”

“ The cables which radiate from the central electric power-house in all directions can be very readily devoted to the furnishing of power to new mines as soon as it is found that the older ones have been proved unprofitable. ”

“ Each 5,000-kilowatt unit is capable of delivering during rush hours an output of 7,500 kilowatts or approximately 10,000 electrical horse power and, setting aside one unit as a reserve, the contemplated ultimate maximum output of the power plant, therefore, is 75,000 kilowatts, or approximately 100,000 electrical horse power. ”

“ The company, needing electric power for its own use, has developed a system deriving its power from a point about thirty miles from the city, where a small stream plunges down the sea coast from the mountain range that runs along it. ”

“ If more than one point of distribution exists on the same transmission line, the regulation at the generating plant must be designed to maintain the desired pressure at only one of these points, leaving regulation at the others to be accomplished by local means. One method of regulation consists in the overcompounding of each generator so that the voltage at its terminals will rise at a certain rate as its load increases. ”

“ It has been found that some electric stations, working twenty-four hours daily on mixed loads of lamps and stationary motors, can deliver energy to an amount represented by the necessary maximum capacity during about 3,000 hours per year. Applying this rule to the present case, the transformers at the sub-station, if loaded to their maximum capacity of 10,000 horse-power by the heaviest demands of consumers, may be expected to deliver energy to the amount of 3,000 × 10,000 = 30,000,000 horse-power hours yearly. ”

“ The accessory apparatus for the production of electric power, and its transmission and distribution to the consumer is the basis of a seminar type course. Each student investigates an assigned topic in some detail and discusses his findings for the information of the class. Prime movers, generator excitation and voltage regulation, feeder voltage regulation, station wiring layouts, switchboards and switching gear, reactors, relays and relay systems, line disturbances and line protection, plant economics and energy rates, industrial motor application and control are topics treated. ”

“ Now that power, generated at any point, however inaccessible for freight handling, may be transmitted in the form of electricity on a simple piece of wire to any convenient point within a hundred or even two hundred miles of the place of production, and by a simple process applied to the operations of machines small or large, simple or complex, the possibilities of the waterfall in supplying power for the manufacturer are greatly enlarged. ”

“ As a partial offset to the low cost of the continuous-current generators and to the absence of transformers, there is the necessity for motor-generators in a sub-station when current for lighting as well as power is to be distributed. ”

“ COST OF CONDUCTORS FOR ELECTRIC-POWER TRANSMISSION.
Electrical transmission of energy involves problems quite distinct from its development. A great water-power, or a location where fuel is cheap, may offer opportunity to generate electrical energy at an exceptionally low cost. ”