US1878752A - Electric signaling - Google Patents

Description

ELECTRIC S IGNALING Filed May 11, 1926 2 Sheets-Sheet 1 III Snbeutoz 2 I\ LUCIEN BEGlN MUN/CAT/fl/V 33 h'w Qbtom PPAEATUS 8 W Sept. 20, 1932. L. BEGIN 1,878,752

ELECTRIC SIGNALING Filed May 11, 1926 2 Sheets-Sheet 2 3513 his au o (mug m 5 mum.

Patented Sept. 20, 1932 UNITED STATES PATENT OFFICE A LUGIEN BEGIN, OF PARIS, FRANCE, ASSIGNOR OF ONE-HALF TO WILLIAM B. WEAVER, OF BIRMINGHAM, ALABAMA, AND HAROLD F. WILHELM, OF NEW YORK, N. Y.

nnnc'rnrc sronanmo Application iiled Kay 11, 1926, Serial No. 108,245, and in France May 30, 1925.

This invention relates to electric signaling and particularly to high frequency electrical wave signaling over existing electrical power transmission lines and various power apparatus associated therewith.

One. of the principal objects of the invention is the provision of an inexpensive, simple, eflicient and safe coupling means betweenthe high-frequency signaling apparatusand the power system over which the signaling is to be effected.

Another object of the invention is the utilization of the inherent capacity reactance to high-frequency waves possessed by various power apparatus for effecting various coupling relationships between the signaling apparatus and existing power systems.

Other objects and advantages of the invention will be apparent from the following disclosure of the invention in which:

Fig. 1 is a schematic diagram of the usual type of power transformer employed in power transmission systems.

Figure 2 is a diagrammatic representation of the various electrical characteristics offered to high-frequency waves by such a transformer.

Figure 3 is a simplified diagrammatic representation of Figure 2.

Figure 4 is a schematic I diagram of the usual type oil circuit breaker.

Fig. 5 is a diagrammatic representation of the various electrical characteristicsofiered to high frequency waves by such a circuit breaker. I

Fig. 6 is'a simplified diagrammatic representation of Fig. 5.

Fig. 7 is a diagrammatic representation of the usual power transformershowin means for eliminating or neutralizing certain undesired characteristics shown in Figures 2 and 3.

Fig. 8 is a schematic diagram of a 3 phase power system in which'the signaling apparatus is coupled to high tension 3 hase lines through the capacity reactance o certain of the power transformers.

Referring to Fig. 1, there is represented a transformer of the type generally used in high-tension power practica The tank enclosing the transformer T is denoted by 1, the magnetic core by 2, the high and low voltage windings by 3 and 4 respectively, with their bushing terminals 56, 7-8, the input and output pipes of the cooling coil by 910, the insulating oil conduit by 11 and the concrete or other base by 12. Figure 2 shows the approximate electrical equivalent of 1 and takes into account the main accessory ef fects. It will be noted that there exists four conductive connections 91011 and 13 and one capacitive connection 14 between the tank 1 and the ground. There is, moreover, a capacitive coupling between the turns of each winding, between the different windings themselves as well as between windings and the frame 12. From the point of view of high-frequencies, the whole arrangement may berepresented by the simplifieddiagram of Figure 3. a

Figure 4 represents a circuit-breaker of the type generally used in connection with the above described power transformer. In this figure 1516 represent the bushing terminals while the oil pipe and the tank are here denoted by 17 18 respectively and the base by 19. Figure 5 shows the approximate electrical equivalent of Figure 4 from the point of view of carrier waves and Figure 6 is a simplified diagram of Figure 5. 'As in the case of Figure 3, resistance 13, between the tank and ground, is that of the base 19, generallyiof concrete,and capacity 14, is that which exists between the tank and the ground.

Referring to Figure 7, in order to utilize the capacity-which exists either between 18 and 15-46, or between 1 and 56 or 78, with a view of effecting a capacitive coupling with the high-voltage wires, it will be seen that it does not 'suflice to insulate the tanks 1, 18, from their respective bases 12, 19, owing to the various other connections 9, 10, 11 and 14 which subsist between said tanks and ground. i

- Now the conduits 9, 10, and 11 by their very character, are bound to remain "at ground potential from the electrostatic point of view. In accordance with the invention it will neverthelessbe possible to suppress them as regards high-frequency currents used in carrier wave signaling. lVith that object in view, insulating tube sections will be inserted in series with the different pipes so as to effect a breech in their electrical conductivity. In certain cases, however, this measure will be insuificient as regards water pipes 9, 10, owing to the electrical conductivity of the water used which contains more or less impurities, and in viewof the conductivityof the sediments which will coat the inner walls of the insulating tube section. It will then be necessary to resort to the arrangementwhich has been represented in Figure 7, said arrangement consisting mainly in shaping the pipes such as to give them an appreciable self-inductance the reactance of which to carrierwaves may then be further increased to. A practical form of realization consists in coiling the pipe around a magnetic core and in shunting the resulting coil by suitable condensers as shown by 21 and 2( )2-1. From the point of view of high frequencies, this'lay out practically amounts to suppressing the conducting action oi 9, 10 and 11 and of any similar conduit. By inserting suitable insulators 22, 22 between the tanks 1, 18, and their respective bases 12, 19, the connections 13, 13, will also be eliminated. The last connection to ground, 14, being of a capacitive nature, it will have to be compensated by a reactance 23, preferably having care to exclude the mass of the base 12 from the electrostatic field by means of the shield 24 used for electrically situating the ground immediately underneath the tank 1. Under those conditions, the tanks 1, 18, will be completely insulated from the ground as regards highfIequency waves and they may be considered as the low-voltage plates of smallcapa cities with respect to the windings 3 or 4 and there may be connected thereto any high frequency circuit such as indicated by 100 intended to be linked with the high-voltagewires. If it is wished to effect a coupling with the conductors leading off the high tension bushing terminals 5-6 only, it will be advisable to suppress the electrostatic susceptance towards 78 by inserting suitable rejector circuits 25 and 26 in series with the latter.

Figure 8 represents atransformer bank star-connected on its high-voltage side and delta-connected on its low' voltage side and the distributed capacity effects ofwhich are utilized for effecting coupling with the highvoltage wires. 2 and 3 together on one side, and conductor 1 on the other side, through the low-voltage side of the transformer. The signaling apparatus 27 is connected on one side to the apex 30 of the triangle through a condenser 31 thus coupling on one side with conductors 2 and 3 in parallel and, on the other side with conductor 1 through the distributed capacity between fi e-6 and an artifical middle-point efl'ectcd on the low-voltage winding of phase 1 by means of the condensers 3636. A rejector 37 may eventually be inserted between the neutral point 38 and the lower terminal 6 on the high-tension side of phase 1 as well as between the corners 39 and 40 of the delta and the low-voltage terminals 7 8 respectively, in order to avoid any capacitive susceptance effects tendingto short circuit the carrier waves at their origin.

\Vhile the various figures relate mainly to circuits using metallic conductors only, it should understood that the invention also extends to their adaptation to circuits in which signalling is carried on between the high-voltage conductors and the ground.

Similarly, it should be understood that by high-tension equipment is meant not only power transformers and circuit-breakers but also all accessory apparatus including that used for metering, lightning and overvoltage protection as well as spa-re apparatus.

While various modifications of the invention have been disclosed, I donot limit myself to the same but may employ such other modifications as come within the spirit and scope of my invention.

I claim:

1. In combination, a container, insulation between said container and ground, a pipe conveying conducting fluid connecting said container and, ground, said pipe being ar ranged" in the form of a coil, and a capacitance shunting said coil to form a trap for alternating current. of a given frequency, whereby grounding of said container by said conducting fiuid is eliminated with respect to said frequency.

2. In combination, a tank, a conduit carrying a conducting fluid connecting said tank and ground, and means for makingthe impedance between said tankand groundhigh, whereby a high alternating current potential may be maintained between said tank and ground with substantially no current leakage.

3. In combination, an electrical apparatus having a natural capacitance to ground, insulating material between said apparatus and ground, an inductance between said apparatus and ground to form a trap with the natural capacitance of said apparatus to ground foralternating current of a given frequenc 4. n combination, a power device casing, means for insulating said casing from ground, a pipe carrying a non-conducting fluid connecting said casing' and ground, an insulator section in said pipe, pipes carrying conducting fluid connecting said casing and ground, said pipes having sections in the form of coils to form indu'ctances, condensers in parallel with said coilsto form traps for given alternating frequency and an inductance between said casing and ground to form a tra with the natural capacity of said casing an ground for said frequency.

5. In an alternatin current, high voltage power s stem, a big voltage transmission line, hig 1 voltage power apparatus compriss ing a casing and an electrical device disposed in said casing, said device being connected to said line, said casing normally having a low impedance to ground for both high signalling frequency and low frmkuency, means for causing a high impedance etween said casing and ground for high signalling frequency but maintaining a low impedance for low frequency, a source of high signalling frequency connected to said line, and means for utilizing the electrical properties of said power apparatus to adapt said transmission line for a channel for high signalling fre- UGHC q y LUOIEN BEGIN.

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