High-tension Line Research Articles

First Measurements with the Spanish Standard for the Absolute Determination of the International Roentgen Unit

THE Laboratory for Radiological Measurements annexed to the Service of Physical Therapy, directed by the author, began operation in 1931. In 1932, there was installed a Piccard compensation electrometer, with which we began to make determinations of the charge of radium containers. Finally, in 1934, we found it possible to adapt to this installation the standard chambers for the absolute measurement of the roentgen unit. Varied circumstances until now have hindered our comparing this standard with the standards of other countries, but it will be done as soon as possible. The arrangement we have employed has been adjusted to the agreements of 1934 between the National Laboratories (1). I.—X-ray Generator We have employed one of the constant high tension machines—“Stabilivolt” S.R.V.—in our Department of Roentgen Therapy. The feeder line presents fluctuations of voltage which, up to this time, we have not found the means of compensating for, by the use of a voltage stabilizer, but we hope to do so in the future, when our equipment will operate as a public service of standards. Notwithstanding, we have practically eliminated these unpleasant oscillations by making our measurements during the hours in which the industrial engines are stopped. In every case, the filament current has been furnished by a storage battery having a capacity of 100 ampere-hours. We have employed two x-ray tubes: one of the Multix model, for voltages up to 110 kv., cooled by thermosiphon, and entirely protected against loss of radiation. The other, of the Metwa Matalix type, up to 200 kv., having the same cooling and protecting system as the former, and a glass window for the passage of the rays. These models are not shockproof, but our new tubes will be so protected in the future, on account of the very efficient screening that the shockproof tubes and conductors possess, which renders unnecessary every other protection against interference from magnetic fields. The milliammeter for measuring the intensity of the current passing through the tube has been calibrated against a precision instrument. We have marked only a fixed point, corresponding to the reading of 4 ma. A second milliammeter, in series with the first, checks the constancy of its readings. The margin of error in the current measurements is of the order of 2 per cent. The high voltage of the Stabilivolt generator has been calibrated by means of a Muller sphere gap, with spheres of 125 mm. diameter. The connection of the spheres with the high tension line has been made through high ohmic resistances, formed by 6 meters of glass tubing of 1 cm. diameter, rolled in a spiral and filled with 95° alcohol. The spark obtained in the sphere gap is very fine, and is spontaneously interrupted, affording periodical discharges (relaxation oscillations).

The Nonuniform Transmission Line

The problem of transmission of periodic waves along a transmission line, whose series impedance and shunt admittance per unit length very as any powers of the distance from some point, is solved. The solution is given in terms of Bessel functions. A length of such a line is considered as a four-terminal network, and the more important parameters of the network are given. From these parameters one derives immediately the attenuation of current and voltage along the line. The solution is given for a line consisting of a number of parts, each of which is of the form described above. The line constants (so-called) need not vary continuously from one part to the next. The results can be applied to the cases of a tapered submarine cable, an overhead line with a pronounced sag, and end effects in a high tension line.

Czechoslovakian Broadcasting Station

ONE of the smallest countries in Europe, Czechoslovakia, now possesses the most powerful broadcasting station in the world. It is situated near Cesky-Brod, some twenty-two miles east of Prague, and is near the geographical centre of Europe. The power of the station is 200 kilowatts, which places it well ahead of the 158-kilowatt station at Warsaw, the next largest. The power is derived from a 15,000-volt three-phase high tension line by Hewittie rectifier valves in oil-filled tanks, duplicated so as to avoid the risk of a breakdown. It was opened on Nov. 21, but the power is temporarily restricted. There are two antennæ towers, each 492 feet high and spaced 820 feet apart. The building has a copper roof, which is connected to the ground by a copper conductor. As there is also a copper mesh screen on the floor of the radio room, all the radio apparatus is actually contained within a copper screen. Switching arrangements enable the station to be worked either at half or full power. In the former case six valves are used in the final stage, and in the latter twelve valves. An ingenious counting device indicates the number of times a valve has operated the circuit breaker, and hence the behaviour of each valve throughout its life is recorded. The engineer supervising the working of the transmitter sits at a ‘monitoring desk’. He listens at various stages to the speech or music passing through the transmitter and so can compare the quality at each point. Push buttons enable him to start up the motor generator sets and the pumps for the water-cooled valves. The wave-length is 486.2 metres, and it will be interesting to listen to this station when it is operating at fullpower.

Lightning Discharges and Line Protective Measures

This paper describes the mechanics of the development of a lightning stroke in a cloud and the formation of a surge on a line. It shows that the energy of a stroke can vary between wide limits so that the actual surge on the line may be of practically any magnitude. Fundamental types of high-tension line construction are analyzed to show the performance that would be obtained with them. Experience obtained on the 220-kv. lines of the Public Service Electric and Gas Company is offered to substantiate the belief that induced surges are of relatively small importance and that the direct stroke is the criterion for good design. The effects of line construction on the character of surges impressed on the terminal substation apparatus is discussed to indicate the degree of protection that would be required.

The Study of the Heart Action with the Roentgen Cinematograph

CINEMATOGRAPHIC roentgenography of the human heart has been accomplished by two principal methods. Photographing with cinema films the image on the fluorescent screen was first accomplished (1) and recently brought to a high degree of perfection (2) by Lomon and Commandon. Full-size roentgenograms of the human heart, taken at fixed instants in the cardiac cycle (3, 4) or in rapid succession (5, 6) have not been of great value until Ruggles (7), with the assistance of Mr. E. P. Fletcher, designed and operated a machine taking fifteen 8×10 in. instantaneous roentgenograms per second. The cinematographic positive prepared by them left nothing to be desired in the sharpness of projection of the motions of the heart, but it is questionable if such a method has any advantage over that of Lomon and Commandon for demonstration or preservation of fluoroscopic findings. Its disadvantage, for such work, is the greater cost and difficulty of operation. For the more important purpose of analyzing the action of the normal and diseased heart the method of Ruggles is indispensable, for it is impossible to measure accurately films in which the borders are even slightly blurred, as occurs in full-size projections of photographs of the fluorescent screen image. Thanks to the generosity of Dr. Ruggles, of the University of California, we have had an opportunity to measure his original films of the normal heart and to use his machine, with the assistance of Mr. Fletcher, to obtain for similar analysis films of the moving heart border in cases of valvular disease. The Machine of Ruggles and Fletcher Regular Eastman Superspeed Duplitized X-ray Film, in strips 8 inches wide and 30 feet long, is drawn through the exposure frame by rubber-covered rollers for a distance of eleven inches, while a mechanism of eccentrics and connecting rods holds the two intensifying screens apart and releases a pair of brake shoes designed to prevent movement of the film during the making of each exposure. When the film has moved eleven inches, the rubber-covered rollers no longer grip it firmly between them, for they are broadly notched, and the brakes are at this instant applied to the edges of the film. The intensifying screens are then forced together, and the new area of film is in place and ready for exposure. The above train of events occupies a total time of approximately 1∕24 second. During this interval the high tension line between the X-ray machine and the X-ray tube has been disconnected by a high tension oil-immersed switch, interposed in the anode line. This switch is operated by a shaft from the rollers which move the film. At the instant that the intensifying screens make contact with the film, the high tension oil-immersed switch closes, remaining so for 1∕40 second.

Alternators for operation on a transmission line

When laying out the design of ah alternator that will be used to transmit power over a long transmission line, it is necessary to consider several factors in addition to the specified full-load rating before one can decide on the relative electric and magnetic loadings of the machine, or even the frame size on which it should be built.In attempting a survey of the problem, the paper was divided into six sections, which may be summarized as follows :—(1) General discussion of the possible instability of an alternator connected to a transmission line.(2) Varying-voltage and constant-voltage ' transmission lines. (3) A more detailed consideration of the alternator, showing that it is possible to determine directly from its open-circuit and short-circuit characteristics the maximum leading kVA with which it can deal at normal voltage, for complete stability down to zero voltage.(4) Effect of the exciter on the stability of the generating unit.(5) Variations in station voltage to be expected when operating the high-tension line switches.(6) Particulars of an alternator built for a 50-period line demanding a charging current equivalent to 8 100 kVA at 11 000 volts.

A. I. E. E. specification for testing high-tension porcelain line insulators

A. I. E. E. specification for testing high-tension porcelain line insulators

Provisional specification for insulator testing: Covering inspection and tests of high-tension line insulators of porcelain, for over 25,000 volts

Provisional specification for insulator testing: Covering inspection and tests of high-tension line insulators of porcelain, for over 25,000 volts

Discussion on “specification for insulator testing — Covering inspection and tests of high-tension line insulators of porcelain, for over 25,000 volts” (engineering data sub-committee), Detroit, Mich., June 25, 1914. (see proceedings for October, 1914)

Discussion on “specification for insulator testing — Covering inspection and tests of high-tension line insulators of porcelain, for over 25,000 volts” (engineering data sub-committee), Detroit, Mich., June 25, 1914. (see proceedings for October, 1914)

Specification for insulator testing: Covering inspection and tests of high-tension line insulators of porcelain, for over 25,000 volts

Specification for insulator testing: Covering inspection and tests of high-tension line insulators of porcelain, for over 25,000 volts

(3) Insulator testing specification for insulators having an operating voltage exceeding 25,000 volts

This specification gives the conditions of tests and inspections which are found best to secure reliable high-tension line insulators for use under the ordinary conditions of power transmission work. It is expected to serve as a skeleton or model specification and may be supplemented by such additional matters as may be appropriate for any particular case.

Insulator Testing Specification for Insulators Having an Operating Voltage Exceeding 25,000 Volts

This specification gives the conditions of tests and inspections which are found best to secure reliable high-tension line insulators for use under the ordinary conditions of power transmission work. It is expected to serve as a skeleton or model specification and may be supplemented by such additional matters as may be appropriate for any particular case.

High-tension porcelain line insulators

High-tension porcelain line insulators

Discussion on “High-tension porcelain line insulators”

Discussion on “High-tension porcelain line insulators”

Uniform specification for high-tension line crossing

Uniform specification for high-tension line crossing

Discussion on “output and regulation in long-distance lines,” and “calculation of the high-tension line.” Frontenac, N. Y., June 29, 1909

Discussion on “output and regulation in long-distance lines,” and “calculation of the high-tension line.” Frontenac, N. Y., June 29, 1909

Calculation of the high-tension line

Neglecting matters of cost, the electrical performance of the high-tension transmission line becomes the critical factor as the quantity of power and distance of transmission become large. The loss and variation of voltage and, to a lesser extent, perhaps, the loss of energy in the line tend to become the dominating features. A careful study of these characteristics is thus most important in planning such a transmission. It is the purpose of the present paper to discuss the calculation of the high-tension line as relating to the important matters of regulation and energy line loss, and with especial reference to the unusually long and high-power lines. For this purpose certain new formulas suited for practical calculations are derived.

Discussion on ``Output and Regulation in Long-Distance Lines,'' and ``Calculation of the High-Tension Line.'' Frontenac, N. Y., June 29, 1909

Discussion on ``Output and Regulation in Long-Distance Lines,'' and ``Calculation of the High-Tension Line.'' Frontenac, N. Y., June 29, 1909

Calculation of the High-Tension Line

Calculation of the High-Tension Line

Discussion on “a new type of insulator for high-tension transmission lines,” and “some new methods in high-tension line construction”, at Niagara Falls, N. Y., June 26, 1907

Discussion on “a new type of insulator for high-tension transmission lines,” and “some new methods in high-tension line construction”, at Niagara Falls, N. Y., June 26, 1907