US2611107A - Electric lightning arrester - Google Patents

Description

p 1952 G. RYDBECK ELECTRIC LIGHTNING ARRESTER 5 Sheets-Sheet 1 Filed June 21, 1951 11 .1 m b T k m d 7 7 W x 5 .9

x I I I I I 3 8 33833 I I I I] I.

Go'sZa/R Sept. 16, 1952 RYDBECK 2,611,107

ELECTRIC LIGHTNING ARRESTER Filed June 21, 1951 5 Sheets-Sheet 2 /A van for C1 RyC/EU/f Sept. 16, 1952 G. RYDBECK 2,611,107

I ELECTRIC LIGHTNING ARRESTER Filed June 21, 1951 3 Sheets-Sheet 3 /Aven for 6632 0. fi dbc r Patented Sept. 16, 1952 UNITED STATES PATENT OFFICE Application June 21, 1951, Serial-No. 232,699

In viweden- September. 24, 11941 Se'ctiohL'PubIic Law GQOIAugust 8,1946 Patent "expires September 24, 1961 (CL BIS-36).

8 Claims.

1 Fora long time 11135138811 01.9811 thata reduction of the lengthof highs-tension .lightning arresters has been mostdesirable; Alpossible solution has been to buildi'together a number of closed lightning arrester units. with: insulating porcelainsto a frame work'in'whichi the lightning current path I is zig-zag. formed. Such an arrangement requires, howevenYmuch space and the capacitance voltage distribution :is' combined with .diificult problems; the. :solutionlof which requires large shielding devices.

Another possibility is to buildup-the arrester in a porcelain cylinderwith'ailarge diameter but with a reduced height, inwhich the arrester units are arranged in a plurality "of columns electrically series-connected. Also in this: case-itiis very dimcult to attain a good voltage; distribution.

The present invention concerns tadesi'gn of lightning-arresters of the. latter kind but using insulating separators iwhichralso serve as condensers aiding to perform the voltage distribution over the arrester. The arrester units are mounted in two or aaplurality of columns side by side, and a pluralityof insulating separators are inserted in them, so that the columns are divided into short pieces'containing gap elements, valve resistor elements, or both, over-which the voltage is ratherlimit'e'd; By the division of the columns into comparatively short pieces'the advantage is. gainedithaton the samellevel there will-notbe any severely highitension between the different columns,. which i would i cause a flash-' over between the columns'ioran uniavorable voltage over the whole .arresten regarded as a unit. The connections between the columns can. either be attained. by separate :metal connections or thereby thatall or'somefof the insulating separators are providediwithconductive coatings and aremade so-large that-'they, 'w-hen interposed in the columns, willreach from'one column to "an adjacent column;

A characteristicfeature of the inventionis that the insulating separators will 'act as condensers coupled in: parallel with the maincurrent path and thus will aid-in equalizingthe voltage distribution before sparkover and at extinguishing;

By increasing thenumber'of columns, the height of the arrester can be considerably reduced, but the reduction of theheight' is limited on one'hand with respect to the-necessary creepingstrength inside the 'arrester; and-on the other hand with respect to the necessary'outer flashover 1 distance. The highest 1 number of -columns whichmay be usedwillcertainly be th'ree to five, dependent =-upon-:the kind of construction elements used.- The electric stressper; unit. of length of the valve resistor columns will :be of the same order of magnitude in all modern-types. of arresters having resistors containing siliconoarbide, whereas the spark .gap elements will require avery different space dependentxon the design.

The principle of the invention will be entirely clear from the accompanying drawings, on which the Figs. 1a-5a schematicallyshow five different embodiments of the invention; whereas Figs. lb- 5bshow the corresponding -equivalent wiring diagrams for these-forms; Figs. 6 and 7 show in section and in a View partly. sectionedanarrester according to Fig. 1.

In Fig. 1, l designates an insulatins cylinder, for instance of porcelain, whichat the lower and upper ends is closed by covers! of metal, which covers also serve as terminals. In the cylinder l, two columns of valve resistor elements consisting of resistor blocks and spark gap-elements are arranged side by side. On the drawing the valve resistor elements are designated by 3 and the spark gap elements by 4. The columns are divided into a plurality of portions by means of insulatingseparators 5. The difierent portions of the columns spaced by the insulating separators 5 are connected in series by means of metal connections 6, which consist of metal sheets I interposedbetween the separators-5 and the valve resistor blocks 3, which sheets are connected by flexible conductors. This embodiment of the invention is one of the simplest that can 'be imagined and is combined with the advantage that the insulating separators can be made from turned porcelain, which is'of great importance when they are double cup-shapedfrom a ceramic material, the side walls then serving toprevent fiashover between the columns.

The form shown in Fig. 2 differs from the preceding one chiefly thereinth'at some of the insulating separators l are made so-large that they can be'interposed into two' adjacent columns, the conductive coatings on the side of these separators thus extendingfrom one column to the other andthus'serving as connections between the columns. The conductive coatings on..the other separators are interconnected by. means. of separate metal connections 8.

When a, steep over-voltage wave reaches a diverter' of the hithertoknown kind, the capacitance current through the spark gaps may be so large that there will be-a considerable voltage drop in the resistors. Due to"thisfactonly a minor part of the *over-voltage will fall 'on the spark gaps, which means an increase of the sparkover voltage of thearrester. For such steep over-voltages the device shown in Fig. 2, however, is combined with the advantage that the valve resistor elements 3', which do not contain spark gaps, will be connected in parallel with the capacitors formed by the larger separators l, which means that the above mentioned increase of the sparkover'voltage is considerably reduced.

The form shown in Fig. 3 has three columns of valve resistor elements and spark gap elements arranged side by side according to the same principle as shown in Fig. 1. The equivalent wiring diagram, Fig. 3b, shows that by this device two capacitance dividers are attained connected in parallel with the chain of resistors and spark gaps.

In the form shown in Fig. 5, all spark gap elements 4 are assembled in one column, whereas the resistor blocks are assembled in two columns arranged side by side with this column. Also this form contains in the same manner as the form shown in Fig. 2 insulating separators 7 extending from one column to another, and smaller separators '5 which are interposed in the resistor columns. Fig. b shows that two capacitance divider chains are attained, which are connected in parallel with the same current path of the diverter. These chains are formed by the capacitance of the small separators 5, but further the resistor blocks 3 are connected in parallel with capacitances formed by the large separators i.

In the form shown in Fig. 4, the spark gap elements, as in Fig. 5, are assembled in one column and the resistors in two columns beside of that column. This form is a modification of the form shownin Fig. 5 in that the small separators 5 and the metal connections 8 are removed. In this form no complete capacitance divider chain isformed, but certain groups of valve resistor elements and spark gap elements are coupled in parallel with capacitors formed by the separators l. In spite of the fact that this form seems to be very simple, it is, however, in comparison with the form shown in Figs. 1-3, combined with the disadvantage that the large separators i cannot be made by turning. This is of course also the case with the device in Fig. 5.

Fig. 6 shows in detail the design of the device indicated in Fig. 1. In this figure, l l is an insulating cylinder, suitably of porcelain, which at both ends is closed by metal covers l2, which are pressed against gaskets is by spring members [4 attached to flanges i5. i2 are further covers closing openings in the flanges l5. In the cylinder, there are two columns of valve resistor blocks or elements it and spark gap elements [1. The spark gap elements consist of metal plates 18 separated from each other by spacers, which may be made from a resistance material and thus serving as grading resistors, these spark gap elements being object of the U. S. A. Patent No. 2,324,102. 29 is a centring bolt of porcelain or some other insulating material The columns are divided into a plurality of portions by means of separators 21 of porcelain or of some ceramic material havinga high dielectric constant- These separators are provided with collars .2, which prevent flashover between the columns. The resistor blocks 16 andspark gap elements l1 are inserted in cylinders 23, preferably of porcelain. In order to ensure a good contact between the different portions of the columns, helical springs 24 are inserted. The connections between the columns are performed by means of metal plates or washers 25 interposed between the resistor blocks and the separators, and interconnected by means of flexible conductors 2B. In order to improve the contact between these metal washers 25 and the insulating material in the separators 2! for attaining the highest possible capacitance, the surface of the separators may be metallized or covered by some conductive coating.

21 is a terminal intended to be used for the connection of an operation counter. that no such one is used, this terminal is con nected to earth. 28 is a collar of insulating material intended to stay the columns at one or several points and thus relieve them from acceleration forces during transport. When the diverter has been assembled, the cylinder H is evacuated and filled with some inert gas and then closed by closing the opening 29 by soldering or welding.

Fig. 7 shows in perspective view the lower end of the diverter according to Fig. 6, the cylinder 5 i being partly broken away and one of the separators 2!, 22 also being opened.

I claim asmy invention:

1. A lightning arrester comprising a plurality of parallel columns of elements, one of said columns containing at least spark gaps and an other containing at least voltage dependent resistances, insulating members separating elements of said columns, said members having on both sides layers of conducting material, means connecting elements of the columns in a series con nection which includes alternately at least one spark gap and at least one resistance at adjacent levels in said columns, said layers being connected at spaced points of said series connection, and the series connection extending from one side of one of the members of a first column to a second column and back to the other side of said member through at least one element of the second column, whereby said member and the layers thereon constitute a condenser connected in parallel with such element of the second column.

In a device as claimed in claim 1, a single housing of insulating material enclosing all said columns.

3. A lightning arrester comprising a plurality of parallel columns of elements, one of said columns containing at least spark gaps and another containing at least voltage dependent resistances, insulating members separating elements of said columns, said members having on both sides layers of conducting material, means connecting elements of the columns in a series connection which includes alternately at least one spark gap and at least one resistance at adjacent levels in said columns, said layers being connected at spaced points of said series connection, and the series connection extending from the top side of one of the members of a first column to the bottom side of one of the members of a second column and back to the lower side of said first member through at least one element of the second column, whereby said first member and the layers thereon constitute a condenser con nected in parallel with such element of the second column.

l. In a device as claimed in claim 3, said members having cylindrical skirts thereon.

5. In a device as claimed in claim 4, the skirts of the members in one column being in partial vertical alignment with those of the members in another column.

6. A lightning arrester comprisingtwo parallel columns of elements, one of said columns containing at least spark gaps and another contain- In the case ing at least voltage dependent resistances, insulating members separating elements of said columns, said members having on both sides layers of conducting material, means connecting elements of the columns in a series connection which includes alternately at least one spark gap and at least one resistance at adjacent levels in said columns, said layers being connected at spaced points of said series connection, and the series connection including a jumper connection extending from the top side of one of the members of the first column to the bottom side of one of the members of the second column located higher than the first member, said series connection then extending through at least one element of the second column to the top side of the next lower member thereof, and then to the bottom side of the first member, whereby said first member and 6 the layers thereon constitute a condenser connected in parallel with such element of the second column.

'7. In a device as claimed in claim 6, said members having cylindrical skirts thereon.

8. In a device as claimed in claim '7, the skirts in one column being in partial vertical alignment with the skirts of the other column.

GGSTA RYDBECK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,476,791 Ackermann July 19, 1949 2,542,805 Fink Feb. 20, 1951

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