US1894338A - Connection for high voltage lines - Google Patents

Description

Jan. 17, 1933. us'rm 1,894,338

CONNECTION FOR HIGH VOLTAGE LINES Filed Jan. 21, 1928 a Sheets-Sheet 1 lln Y 5 x 1 a 9,? a U .\M M I J 5::

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Sm f f E I 23 E 3 5 0 l INVENTOR fi ATTORNEY Jan. 17, 1933. A. o. AUSTIN 1 1,894,338

CONNECTION FOR HIGH VOLTAGE LINES Filed Jan. 21. 1928 a Sheets-Sheet 2 UUUUU Vol/aye 0/1 L000.

ATTORNEY Fly/2' BY Jan. 17, 1933. A. o. AUSTIN CONNECTION FOR HIGH VOLTAGE LINES Filed Jan. 21, 1928 3 Sheets-Sheet 5 INVENTOR @L:ZM am Wed @040 ATTORNEY Patented Jan. 17, 1933 UNITED STATES PATENT OFFICE ARTHUR O. AUSTIN, OF NEAR BABIBERTON, OHIO, ASSIGNOR, BY MESNE ASSIGNMENTS, TO THE OHIO BRASS COMPANY, OF MANSFIELD, OHIO, A CORPORATION OF NEW JERSEY CONNECTION FOR HIGH VOLTAGE LINES Application filed January 21, 1928.

This invention relates to high potential connections and has for its object the provision of a connection with a high voltage line which will be simple and inexpensive and by means of which energy may be derived from the line for purposes of synchronizing, determination of voltage, derivatlon of power, or other purposes where the amount of energy required is not excessive and where expensive transformer mechanism is not desirable. Other objects andadvantages will appear'from the following description.

The invention is exemplified in the comb nation and arrangement of parts shown n the accompanying drawings and described in the following specification, and 1t 1s more particularly pointed out in the appended claims.

In the drawings- Figure 1 is a partly diagrammatic elevation showing condensers and connecting c rcuits for one embodiment of the present 1nvention.

Figure 2 shows a series of curves illustrating the effects of one feature of the invention.

Figure 3 is a circuit diagram showing a slightly modified arrangement of the invention.

Fig. 4 is a circuit diagram showing a further modification of the invention.

Fig. 5 is a diagram of the circuit used in obtaining the curves of Fig. 2.

In connecting very high voltage lines it is frequently desirable to know the voltage on the lines at the time they are connected and to be able to synchronize the two different lines. In general this has been carried out in two different ways. One has been by means of a condenser which we shall call the electrostatic method. In general. the condenser for this work has been made up of high voltage insulators whose capacity and energy is "ery much limited. The more common method has been to step the voltage down from the line by means of a potential transformer, potential transformers being used on the respective lines to be synchronized. The phase relation of the two lines can then be Serial No. 248,471.

determined by a synchronoscope or by means of lights in a manner well known in the art. Still another method of synchronizing has been to use a capacity or condenser coupling such as that afforded by a bushing insulator. Owing to the fact that the energy available in this way is very much limited, the energy has been amplified by the use of one of the well known Vacuum tubes or kenetrons. IVhile this method makes it POSSibl': to provide ample energy, it is necessary in most cases to provide special bushings and considerable auxiliary equipment is necessary to provide sufficient energy to operate the synchronoscopes or other equipment, which tends to make the system complicated and robs it of some of its reliability.

In the improved method of supplying sufficient energy for the determination of voltage or for synchronizing according to the present invention, ample energy is provided so that the indication of voltage may be shown at a considerable distance from the electrostatic coupling. As the equipment is simple and rugged, it lends itself readily to installations in the open. It may be applied to the ordinary synchronoscopes without additional amplifying apparatus, even though the synchronizing indicator is located at a very considerable distance from the high voltage lines to be synchronized.

An installation is shown connected to a single phase only. It is evident, however, that connections may be made between more than one phase, if desired. If the phase rotation is not correct, it is evident, however, to anyone familiar with the art that all that is required is to determine the relation of a corresponding phase on each line.

Fig. 1 shows one form of the improved method of supplying energy for indicating voltage or for synchronizing. The same arrangement of condensers and transformers may be used for tapping a high voltage line where power is desired in limited quantities for various purposes without going to the expense of providing a high voltage transformer, which would be very expensive.

The conductors of the two lines to be synchronized are shown by and 11 respectively. A condenser composed of elements 12' is connected electrically to the power condiuctor through fuse 13, Fig. 3, and resistance 14. The condenser may be of any desired capacity and made of enough units in series to provide a factor of safety sufiicient to withstand line voltage. a

One difference between this scheme and the other electrostatic schemes heretofore used is the use of a larger coupling condenser and a transformer placed between the coupling condenser and ground. While it ed by the voltage, and the capacity of the line to is possible simply to use a larger coupling condenser, the voltage placed on the winding running from the condenser will be limitcapacity of the condenser, the'line ground. If the line to ground is opened, a very high voltage will exist and may endanger life. For this reason it has not been feasible to use coupling condensers of larger size so that synchronizing could be carried on at a distance. Another disadvantage in using large condensers without a transformer is that the voltage to ground may vary considerably depending upon the length of .line. In operation the current passes through the condenser 12, flows through the primary winding 15, energizing the magnetic core 16 of the transformer and secondary winding 17. After passing through the winding 15 the current may be carried through a primary winding 18 of another transformer which will energize its core 19 and secondary winding 20. The current then passes to ground.

Duringlightning storms, switching surges, or abnormal voltages on the transmission line, it is evident that the condensers will permit the passage of a very large current at a high frequency. Owing to the reactive drop in the transformers, the transformer 'might be broken down by the drop in potential unless protected in some way. Several methods of providing this protection may be used, either singly or collectively, depending upon the conditions existing in the particular installation. Where the resistance 14 may be large such as from 50,000 to 500,000 ohms, the condensers will still pass enough current at normal frequency to give the desired indieatiombut at the high frequencies the drop impotential instead of being largely across the condensers, will take place over the resistance and thereby afford protection to the transformer, providing, however, that 'a limiting or discharge gap 21 is provided or a condenser 22 in multiple with the trans former is used.

Since the regulation of a circuit taking power from a condenser is' very poor owing to the well known electrical laws, this together with the dangerous voltage on the low side of the condenser when the circuit on the low side is open, tends to limit its use as explained previously. To offset this difficulty, the transformer having primary or high voltage winding 15 and core 16 is used giving an inductive reactance in series with the.

wound on the core 16 and a leakage path for the magnetic flux is formed by a tongue 38 having a short air gap between it and the opposite leg of thecore. This produces a transformer having a high inductive reactance and in which the magnetic flux will practically all flow through the core of the secondary at no load but in which there willbe increasingleakage as the load increases. The curves shown in Fig. 2 were derived from the circuit arrangement shown in Fig. 5 in which a transformer having a high leakage between windings was employed. It will be seen that when a voltage of 30 k. v. was impressed on the conductor line, the voltage remained approximately constant for 10 to 100 volt amperes on the secondary. By operating in this part of the curve, ample power can be obtained for synchronizing, determination of voltage or other purposes even through a circuit extending to a point quite remote from the transformer. way, it is possible to vary the duty imposed on the winding 17 over an appreciable range without seriously affecting the voltage.

It is evident from the above considerations that this method of using condensers and transformers provides an easy means of tapping very high voltage lines inexpensively where the amount of power required is not very great. By providing taps, either on the high voltage winding or the low voltage winding of the transformer, it is possible to make the equipment applicable for a wide range of voltage conditions on the line, even though the condenser remainsv approximately the same.

It is evident that the proper relation may be setup by changing both the condenser and high voltage transformer winding to set up the desired saturation in the transformer core.

Where lights are used to synchronize, it is possible to have an indication of voltage on each circuit in addition to the lamps used in synchronizing. There is sufficient energy so that ordinary 110 volt lamps of fair candle power may be used for the synchronizing and With a transformer made in this the synchronizing may be accomplished by either the bright or dark method as preferred.

Since the current flowing through a condenser is directly proportional to the voltage, frequency, and electrostatic capacity of the condenser, it may be used in conjunction with a suitable current measuring instrument for the indication of voltage, as in most systems the frequency is held within very close limits for this purpose, but in order to do this, it

is necessary to protect the instrument from surges as the drop in voltage across the instrument during the disturbance may readily .break down the winding and very elaborate means for protection are provided as the instrument must be fairly sensitive owing to the small current involved. If, however, a transformer having a winding 18 and a core 19 is used and so proportioned that the volt ampere output is proportional to the current flowing through the primary winding 18, the voltage on the line may be indicated by a suitableinstrument 23 inthe secondary circuit 20 of this transformer. lVhere'the instrument 23 is a low resistance instrument, the windings 18 and 20 together with the core 19 form a current transformer which is used to indicate voltage. This or the synchronizing circuit may be used to operate relays for the control of the system if so desired.

It is evident that the transformer scheme thus avoid the cost of a high voltage condenser. This is quite important where a carrier current system Is already installed and,

it is desired to utilize the coupling condenser as outlined above. In its application to a carrier current coupling condenser, the transformer may be attached in one of two ways.

lVhere a transformer is attached to a carriercurrent coupling condenser as shown in Fig. 1, the carrier current coupling is attached to the bottom of the stack of condensers 12 which is insulated from the ground. A limiting gap 32 is used between the ground side of the coupling condenser and ground. Since the carrier current lead 30 has a low impedance to ground at normal frequency, the ground side of the condenser may be regarded as at ground potential under normal frequency conditions. If the primary side of the transformer is tapped into the condenser at 33 and the other side attached to ground, it will be seen that the transformer will be energized by the voltage at this point, part of the current flowing through the transformer winding to ground and part through the lower portion of the condenser. \Vhere the voltage on the condenser is high, the transformer tendsto relieve the lower portion of the condenser from duty unless the transformer has considerable reactance. The impedance of the transformer circuit, however, prevents the high frequency carrier current from be ing by-passed to ground. Where it is desired to limit the current through the transformer, a condenser 34 may be placed between the point 33 and the end of the transformer winding 15. It is evident that even where he condenser 34 is used, the major portion of the coupling condenser is furnished by the condenser only for the carrier current system. This method therefore provides an inexpensive method for coupling even to a very high voltage line such as a 220,000 volt line where condensers are already in the circuit. The method, even where the condensers are not already in use for carrier current, is probably much cheaper and far more reliable than that which may be provided by a potential transformer installation.

It is evident that the scheme disclosed makes it possible to provide light or power at various points along a transmission line at relatively small expense. By providing suitable synchronizin switches, switching stations may be suita ly equipped, even though there are not the ordinary facilities presentusually found in a station. Where this system is used, all that is necessary to connect two high potential lines is to provide suitable means for closing the two circuits when synchronized, which may be carried out by a suitable air break switch or oil circuit breaker.

The secondaries of the transformers connected with the two lines to be synchronized are connected by conductors 24 provided with a switch 25 and lights 26 or other means for indicating when the lines are in synchronism. Lights 27 may be provided to indicate when the transformers are energized.

In Fig. 4 the circuit is shown for connecting the secondary windings 17 with a synchronoscope 28. The synchronoscope 28 18 connected with contact sockets 29 provided with starting-and running plugs 36 and 37 for connecting the synchronoscope with the secondary windings of the transformers for either starting or running connection.

I claim 1. Means for Withdrawing energy from a high voltage alternating current transmission line comprising a condenser having one terminal connected with said line, a resistance in series with said condenser, a transformer having its primary winding in series with said condenser, current receiving means in circuit with the secondary of said transformer, and a condenser in parallel with the primary winding of said transformer.

2. The combination with a high voltage transmission line having carrier current apparatus connected therewith, comprising condenser units in series, of an indicating circuit connected with said condensers between units thereof, said indicating circuit including a condenser and a transformer, the priformer,

set including a number of series at a point closer mary winding of said transformer being in series with said condenser and an indicator 0 a l in series with the secondary winding of said transformer,'said transformer having a low reluctance leakage path between the windings thereof. 3. The combination with a high potential transmission line, of a condenser having one terminal thereof electrically connected with said transmission line, said condenser-comprisingsets oflcondenser units in series,

condenser units in parallel, carrier current apparatus connected with said condenser at one point thereof, a transformer connected with said condenser at a different point thereof and separated from said carrier current connection by a set of condenser units, a condenser in series with said ,transformer and in parallel with said last named set of condenser units, and an indicating instrument in the secondary circuit of said transformer. 1

4. Means for diverting energy from a high oltage alternating current transmission line comprising a condenser having a plurality of condenser units in series, one terminal of said series being connected with said transmission line and the other terminal of said series being grounded, a transformer having one terminal of its primary winding connected to said condenser series at a point in termediate the ends of said series, an electrical translating device connected to said to the grounded end thereof than the connection with said transand current receiving means in series with the secondary of said transformer. 5. Means for diverting energy from a high voltage alternating current transmission line comprising a condenser having a plurality of condenser units in series, one terminal of said series being connected with said transmission line and the other terminal of said series being connected t rough an electrical translating device to ground, a transformer having one terminal of its'primary winding connected to said condenser series at a point intermediate the ends of said series, current receiving means connected with the secondary winding of said transformer, means in parallel with the primary of said transformer for limiting the voltage impressed on said primary, and a condenser unit electrically connected in series with said primary and between said primary and its point of connection with said condenser series to prevent said point of connection in said series from being grounded when said voltage limiting means is short-circuited. v

' 6. Means for diverting energy from a high voltage alternating current transmission line .coniprising'a condenser having a plurality for condenser sections in series, each section comprising a plurality of units in parallel,

each

one terminal of said series being connected with said transmission line and the other terminal of i said series being grounded through an electrical translating device, a transformer having one terminal of its primary windingconnected to said condenser series at a point intermediate the ends of said series, a current receiving means connected with the secondary of said transformer, an arcing gap in parallel with the primary of said transformer for limiting the voltage impressed on said primary, and a condenser unit electrically connected in series with said primary and between said primary and its point of connection with said condenser series to prevent said point of connection in said condenser series from being grounded when said arcing gap is short-circuited by an elec= trical discharge.

7. Means for withdrawing energy from a high voltage alternating current transmission line comprising a condenser having one terminal connected with said transmission line and the other terminal thereof grounded, said condenser comprising a plurality of main condenser sections in series, a supplemental condenser section in series with a part of said main'condenser sections adjacent the transmission line and in parallel with a main condenser section adjacent the grounded end of said series, a transformer mary winding in series with said supplemental condenser section and electrically connectedbetween said supplemental condenser section and ground, and current receiving means in circuit with the secondary of said transformer.

8. The combination with a high potential transmission line, of a condenser stack comprising a plurality of sections in'series having one terminal thereof connected with said transmission line, carrier current apparatus connected between the other terminal of said condenser stack and ground, a branch circuit in series with a portion of said condenser stack and in parallel with another portion of said stack, said branch circuit comprising a condenser unit connected with said condenser stack at a point intermediate the ends thereof, and a transformer having its primary winding in series with said condenser unit.

9. A condenser coupling comprising a plurality of condenser sections in series, one terminal of said series being connected with a high potential transmission line, a carrier current circuit connected between the other terminal of said series and ground, and a transformer circuit in series with certain of said condenser sections next adjacent said transmission line and in parallelwith certain of said sections adjacent the ground connection of said stack, said transformer circuit comprising a condenser unit, a trans- Ill ARTHUR O. AUSTIN.

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