CA1078478A - Insulator for electrodes inside an electrical switch gear - Google Patents
Insulator for electrodes inside an electrical switch gearInfo
- Publication number
- CA1078478A CA1078478A CA254,633A CA254633A CA1078478A CA 1078478 A CA1078478 A CA 1078478A CA 254633 A CA254633 A CA 254633A CA 1078478 A CA1078478 A CA 1078478A
- Authority
- CA
- Canada
- Prior art keywords
- insulator
- electrodes
- insulating
- electrode
- discharges
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B17/00—Insulators or insulating bodies characterised by their form
- H01B17/14—Supporting insulators
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02G—INSTALLATION OF ELECTRIC CABLES OR LINES, OR OF COMBINED OPTICAL AND ELECTRIC CABLES OR LINES
- H02G5/00—Installations of bus-bars
- H02G5/06—Totally-enclosed installations, e.g. in metal casings
- H02G5/066—Devices for maintaining distance between conductor and enclosure
Landscapes
- Insulators (AREA)
- Installation Of Bus-Bars (AREA)
- Gas-Insulated Switchgears (AREA)
- Insulating Bodies (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
An insulator for insulating electrodes at different potentials from each other and for supporting such electrodes in relation to each other. More particularly, the insulator is used for insulating and supporting internal and external conductors in encapsulated electrical switch gear preferably insulated with SF6 gas. In order to hold electrical conductors in a capsule and insulate them from each other, use is made of insulators having both adequate mechanical and electrical strength. In such arrangements, there is a danger that con-tamination may cause sliding discharges which may damage the insulator. In known insulator designs to avoid sliding discharges, a small amount of dirt on one of the electrodes can result in discharges which eventually lead to permanent impari-ment of insulator behavior. The insulator according to this invention proposes to further reduce the danger of sliding discharge. Accordingly, the surface of the insulator extending over the insulating path is of a configuration such that electric-flux lines extending between the electrodes, and passing from the electrode regions which are outside the intersection of electrode and insulator surfaces, run their entire length externally of said insulator.
An insulator for insulating electrodes at different potentials from each other and for supporting such electrodes in relation to each other. More particularly, the insulator is used for insulating and supporting internal and external conductors in encapsulated electrical switch gear preferably insulated with SF6 gas. In order to hold electrical conductors in a capsule and insulate them from each other, use is made of insulators having both adequate mechanical and electrical strength. In such arrangements, there is a danger that con-tamination may cause sliding discharges which may damage the insulator. In known insulator designs to avoid sliding discharges, a small amount of dirt on one of the electrodes can result in discharges which eventually lead to permanent impari-ment of insulator behavior. The insulator according to this invention proposes to further reduce the danger of sliding discharge. Accordingly, the surface of the insulator extending over the insulating path is of a configuration such that electric-flux lines extending between the electrodes, and passing from the electrode regions which are outside the intersection of electrode and insulator surfaces, run their entire length externally of said insulator.
Description
The invention relates to an insulator for insulatirg electrodes at different potentials from each other and for supporting such electrodes in relation to each other, more particularly for insulating and supporting the lnternal and external conductors in encapsulated electrical switchgear.
For the purpose of holding electrical conductors in a capsule, and insulating them from each other, use is made o~
insulators which must have not only adequate mechanical strength but also adequate electrical strength. Whereas the area between the internal and external conductors contains an insulating gas, for example SF6, or an insulating liquid, so that flash-overs can occur in this area only under certain conditions, there is a danger, in the case of supporting insulators, that contamination may cause creeping or sliding discharges which may damage the insulator, For this reason, insulators of'this kind are designed in accordance with specific criteria, including steps for extending the creepage path, in one design, this is achieved by providing the contour of the insulator with ribs (see "Elektrizi-tatswirtschaft", 73, 1974, Vol 5, pages 124 to 128). Other insulators are designed in a manner such that the tangential field strength along the insulator is kept approximately constant (ISH Vol. 1972, pages 1 to 8). Again, other insulators are designed in such a manner that the tangential and perpendi-cular field strengths do not exceed maximal values and/or so that the sum of these field strèngths does not exceed a maximal value.
In these known designs, no account was taken of the fact that there are lines of flux which start on one of the electrodes at difEerent potentials facing each other in the gas-or liquid-filled area, which impinge upon the' surface of the insulator, and which penetrate thereinto. If there is a small - 1 - ,~
,' ' ,' ~ .' ;' ' , ` ' '' , - ~ : , ~` 31 07847351 amount of dirt upon one of the electrodes, discharges occur.
These discharges follow the lines of flux and impinge upon the surface of the insulator, where they may easily lead to a breakdown thereof, as a result of the known low field-strength requirement for sliding discharge mechanisms. As already indicated above, the resulting sliding flash-over easily leads to permanent impairment of insulator behaviour, in contrast to any breakdown that may occur in the free gas or liquid-filled area.
It is the purpose of the invention to design an insulat-ing element or insulator of the type mentioned at the beginninghereof in such a manner that the danger of sliding discharges is still further reduced.
This purpose is achieved in that the surface of the insulator extending over the insulating path is of a configuration such that the electric-flux lines running between the electrodes, and passing from the electrodes out of the insulator, always run ~-for their entire length externally of the insulator.
A further improvement may be obtained by ensuring that the surface of the insulator along the insulating path is of a configuration such that the integral of the perpendicular field strength, along the interface between the insulator and the surrounding gas, is approximately zero. ;
Thus the object of the invention is a rule governing the configuration of the surface of an insulator in order to ~-prevent any of the lines of flux passing out of the electrodes in the gas area from impinging upon the surface of the said insulator and thus penetrating thereinto. It is obviously possible to apply the same rule when a liquid is used instead of a gas as an insulating medium between the two electrodes. The desired contour 30 is obtained mainly by numerical calculation of the electric fields, the overall insulator-electrode arrangement being improved by iterative calculation, using the said numerical field calculation.
. . ~
.
``` 10~8~7~3 In this connection, account must be taken of all factors, such as the relevant dielectric constants, the contours of the interface, and the potentials and contours of the electrodes. ~he objective of the calculation may be regarded as having been achieved when, with the tolerances still maintained, a mathematical investigation of the lines of flux provides a line which passes through the points where the edges of the insulator meet the electrodes and which does not impinge upon the surface of the electrode. This rule of configuration provides an insulator which is a considerable improvement as compared with ribbed insulators, for example, or other known insulators, especially from the point of view of the insulating properties thereof.
In addition to this, attention must be paid to the rule according to which the integral of perpendicular field stre~gth along the surface is approximately zero, this latter rule serves almost as a "test~' and optimizing rule.
The concept of the invention may be applied to almost any desired electrode arrangement, with not only two-dimensional, but also three-dimensional designs being conceivable. It is furthermore possible to apply the concept of the invention to insulator arrangements having two or more electrodes and with potentials which are the same, different, or freely adjusted.
In accoxdance with a specific ~mbodiment of the invention, there is provided, an insulator, having two ends, for insulating electrodes at different potentials from each other and for supporting such electrodes, at either end thereof, in spaced relation to each other in surrounding insulating medium, the insulator having a surface extending over an in-sulating path between said two ends, characterized in that the insulator is provided with a narrowed zone between said two ends, the cross sectional view of which shows a substantially _ 3 _ ..... .
.: - : - , . , ,. .:. - ~ : . : .
~L07~47~
\
waist contoured form, said narrowed zone extending between the outer extre~ities of both said ends, said surface con-figuration being such that electric-flux lines extending between said electrodes and passing from electrode regions which are outside the intersection of electrode and insulator surfaces, run for their entire length externally of said insulator, The invention is explained hereinafter in greater detail in conjunction with the examples of embodiment illus-trated in the drawing, wherein:
FIGURES 1 and 2 show two designs of known insulators;
FIGURES ~3 and 3a also show a known insulator;
- FIGURES 4 to 6 show an insulator according to the invention;
FIGURE 7 shows the pattern of the perpendicular field strength over the developed contour of the insulator, and , ~1)7847~3 FIGURE 8 show the pattern of the lines of flux in the case of an insulator according to the invention.
In the case of two electrodes facing each other and spaced apart, the reference numeral 1 always indicates the electrode which is at the higher potential, whereas the numeral 2 always indicates the electrode which is at the lower potential.
Arranged in the space between electrodes 1 and 2 is a space which bears different reference numerals in the different figures.
In the examples illustrated, the areas to the left and right of the insulator contain an insulating gas, namely SF6.
Insulator 3, in Figure 1, is thicker in the central area between electrodes 1 and 2 than at the junctions between electrode l/insulator 3 and insulator 3/electrode 2. Two lines of flux 4,5 are shown in the figure, the said lines emerging from electrodes 1,2 in areas outside insulator 3 and entering into the said insulator at points I and II.
Figure 2 shows an approximately S-shaped insulator 6 of approximately the same thickness throughout. In this case, a line of ~lux 7, chosen more or less at random, enters the insulator at point III and leaves it at point IV.
Figure 3 shows an insulator 8, the sides of which are perfectly parallel and are perpendicular to the surfaces of electrodes 1 and 2. In this case, the lines of flux may not enter the insulator as they do in Figures 1 and 2. Since in practice it is impossible to obtain cast-resin insulators with absolutely flat surfaces, it is impossible to guarantee that a line of flux will not enter the insulator, for instance, at an irregularity, thus producing a sliding discharge. This possibility is shown in Figure 3a which is a cross section, on a greatly enlarged scale, through an insulator having two projections 10,11 produced by -~
roughnesses in the finished insulator. A line of flux running ~ ~07847~
very close to the surface of the insulator, and marked 12, enters projections 10 and 11 and causes sliding discharges at points V
and VI (the points relating to projection 10 are not indicated).
An insulator designed in accordance with the invention is shown in Figures 4 and 5. Along the insulating path between electrodes 1 and 2, insulator 12 has a total of three different areas 13, 14, 15 areas 13 and 14 being wider than area 15. In this case, a line of flux 16 emerges from electrodes 1, 2 within insulator 12, and passes out of the insulator 12 at points VII
and VIII. In the case of a line of flux 17 which emerges from electrodes 1, 2 at the point where the contour of insulator 12 meets electrodes 1, 2, i.e. points B or A, it will be seen that this line of flux is at all times outside the insulator.
The same applies to line of flux 18. Although dirt upon the surface of electrode 1 or 2 may produce a discharge, but if this -discharge follows line of flux 17, it no longer impinges anywhere upon the insulator, and no sliding flash-over can occur. Thus the contour of insulator 4 shown in Fig. 4 is optimal. Even minor deviations from the contour shown in Figure 4 (see Figure 5) at worst result in the line of flux emerging from electrode 2 at point B and impinging upon the surface of the insulator at point IX, after passing for a considerable distance through the insulat-ing gas or liquid. Because of the long path of the line of flux through the gas or liquid, there is no longer any sliding dis-charge at point IX, and the advantage of the solution according to Figure 4 is therefore fully retained.
Figure 6 shows an insulator arrangement in which low-potential electrode 2 is of the same shape as electrode 2 in Figures 1 to 5, whereas electrode 25, which is at a higher potential, has an aerofoil-shaped cross-section selected merely at random. Insulator 26, located between electrodes 2 and 25 is designed in such a manner that a line of flux terminating at . ,.~ .
: .
. . ' . - ' ~' .'; ' :
0~7~3~ 7~3 points A and B at electrodes 2 and 25 does not penetrate the surface of the insulator at any location.
Figure 7 shows the perpendicular field strength along the interface in Figure 8, the said interface being marked 30.
Space 31, to the right of the said interface, is outside the insulator, whereas space 32 is inside the insulator. If the perpendicular field-strength pattern is followed along contour 30, the pattern shown in Figure 7 is obtained.
Now contour 30 is optimal if the integral of the perpendicular field strength along the development equals zero, i.e. if the area marked + in Figure 8 (and 33 in Fig. 7) is equal to the area below the abscissa, marXed 34 in Figure 7.
The configurational rule requiring that the insulator be designed in a manner such that the integral of the perpendicular field strength above the interface between the insulator and the surrounding SF6 gas be approximately zero, can be used only upon one condition. If insulator 3 in Figure 1 is considered, it will be observed that, even when there is a bulge in the middle, that is, ~hen the configuration is convex, the perpendicular field strength follows a similar pattern, as shown in Figure 7, but the sign is changed. Thus, if the configuration of the insulator is to be optimal, both rules must be observed simultaneously: on the one hand, the lines of flux must not enter the insulator (as in the case of insulator 12 in Figure 4) and, on the other hand, the integral of the perpendicular field strength over the interface ~
must bé approximately zero. This latter rule of configuration is ~-therefore only a klnd of ~'test" of whether the insulator is optimal.
. ' .
For the purpose of holding electrical conductors in a capsule, and insulating them from each other, use is made o~
insulators which must have not only adequate mechanical strength but also adequate electrical strength. Whereas the area between the internal and external conductors contains an insulating gas, for example SF6, or an insulating liquid, so that flash-overs can occur in this area only under certain conditions, there is a danger, in the case of supporting insulators, that contamination may cause creeping or sliding discharges which may damage the insulator, For this reason, insulators of'this kind are designed in accordance with specific criteria, including steps for extending the creepage path, in one design, this is achieved by providing the contour of the insulator with ribs (see "Elektrizi-tatswirtschaft", 73, 1974, Vol 5, pages 124 to 128). Other insulators are designed in a manner such that the tangential field strength along the insulator is kept approximately constant (ISH Vol. 1972, pages 1 to 8). Again, other insulators are designed in such a manner that the tangential and perpendi-cular field strengths do not exceed maximal values and/or so that the sum of these field strèngths does not exceed a maximal value.
In these known designs, no account was taken of the fact that there are lines of flux which start on one of the electrodes at difEerent potentials facing each other in the gas-or liquid-filled area, which impinge upon the' surface of the insulator, and which penetrate thereinto. If there is a small - 1 - ,~
,' ' ,' ~ .' ;' ' , ` ' '' , - ~ : , ~` 31 07847351 amount of dirt upon one of the electrodes, discharges occur.
These discharges follow the lines of flux and impinge upon the surface of the insulator, where they may easily lead to a breakdown thereof, as a result of the known low field-strength requirement for sliding discharge mechanisms. As already indicated above, the resulting sliding flash-over easily leads to permanent impairment of insulator behaviour, in contrast to any breakdown that may occur in the free gas or liquid-filled area.
It is the purpose of the invention to design an insulat-ing element or insulator of the type mentioned at the beginninghereof in such a manner that the danger of sliding discharges is still further reduced.
This purpose is achieved in that the surface of the insulator extending over the insulating path is of a configuration such that the electric-flux lines running between the electrodes, and passing from the electrodes out of the insulator, always run ~-for their entire length externally of the insulator.
A further improvement may be obtained by ensuring that the surface of the insulator along the insulating path is of a configuration such that the integral of the perpendicular field strength, along the interface between the insulator and the surrounding gas, is approximately zero. ;
Thus the object of the invention is a rule governing the configuration of the surface of an insulator in order to ~-prevent any of the lines of flux passing out of the electrodes in the gas area from impinging upon the surface of the said insulator and thus penetrating thereinto. It is obviously possible to apply the same rule when a liquid is used instead of a gas as an insulating medium between the two electrodes. The desired contour 30 is obtained mainly by numerical calculation of the electric fields, the overall insulator-electrode arrangement being improved by iterative calculation, using the said numerical field calculation.
. . ~
.
``` 10~8~7~3 In this connection, account must be taken of all factors, such as the relevant dielectric constants, the contours of the interface, and the potentials and contours of the electrodes. ~he objective of the calculation may be regarded as having been achieved when, with the tolerances still maintained, a mathematical investigation of the lines of flux provides a line which passes through the points where the edges of the insulator meet the electrodes and which does not impinge upon the surface of the electrode. This rule of configuration provides an insulator which is a considerable improvement as compared with ribbed insulators, for example, or other known insulators, especially from the point of view of the insulating properties thereof.
In addition to this, attention must be paid to the rule according to which the integral of perpendicular field stre~gth along the surface is approximately zero, this latter rule serves almost as a "test~' and optimizing rule.
The concept of the invention may be applied to almost any desired electrode arrangement, with not only two-dimensional, but also three-dimensional designs being conceivable. It is furthermore possible to apply the concept of the invention to insulator arrangements having two or more electrodes and with potentials which are the same, different, or freely adjusted.
In accoxdance with a specific ~mbodiment of the invention, there is provided, an insulator, having two ends, for insulating electrodes at different potentials from each other and for supporting such electrodes, at either end thereof, in spaced relation to each other in surrounding insulating medium, the insulator having a surface extending over an in-sulating path between said two ends, characterized in that the insulator is provided with a narrowed zone between said two ends, the cross sectional view of which shows a substantially _ 3 _ ..... .
.: - : - , . , ,. .:. - ~ : . : .
~L07~47~
\
waist contoured form, said narrowed zone extending between the outer extre~ities of both said ends, said surface con-figuration being such that electric-flux lines extending between said electrodes and passing from electrode regions which are outside the intersection of electrode and insulator surfaces, run for their entire length externally of said insulator, The invention is explained hereinafter in greater detail in conjunction with the examples of embodiment illus-trated in the drawing, wherein:
FIGURES 1 and 2 show two designs of known insulators;
FIGURES ~3 and 3a also show a known insulator;
- FIGURES 4 to 6 show an insulator according to the invention;
FIGURE 7 shows the pattern of the perpendicular field strength over the developed contour of the insulator, and , ~1)7847~3 FIGURE 8 show the pattern of the lines of flux in the case of an insulator according to the invention.
In the case of two electrodes facing each other and spaced apart, the reference numeral 1 always indicates the electrode which is at the higher potential, whereas the numeral 2 always indicates the electrode which is at the lower potential.
Arranged in the space between electrodes 1 and 2 is a space which bears different reference numerals in the different figures.
In the examples illustrated, the areas to the left and right of the insulator contain an insulating gas, namely SF6.
Insulator 3, in Figure 1, is thicker in the central area between electrodes 1 and 2 than at the junctions between electrode l/insulator 3 and insulator 3/electrode 2. Two lines of flux 4,5 are shown in the figure, the said lines emerging from electrodes 1,2 in areas outside insulator 3 and entering into the said insulator at points I and II.
Figure 2 shows an approximately S-shaped insulator 6 of approximately the same thickness throughout. In this case, a line of ~lux 7, chosen more or less at random, enters the insulator at point III and leaves it at point IV.
Figure 3 shows an insulator 8, the sides of which are perfectly parallel and are perpendicular to the surfaces of electrodes 1 and 2. In this case, the lines of flux may not enter the insulator as they do in Figures 1 and 2. Since in practice it is impossible to obtain cast-resin insulators with absolutely flat surfaces, it is impossible to guarantee that a line of flux will not enter the insulator, for instance, at an irregularity, thus producing a sliding discharge. This possibility is shown in Figure 3a which is a cross section, on a greatly enlarged scale, through an insulator having two projections 10,11 produced by -~
roughnesses in the finished insulator. A line of flux running ~ ~07847~
very close to the surface of the insulator, and marked 12, enters projections 10 and 11 and causes sliding discharges at points V
and VI (the points relating to projection 10 are not indicated).
An insulator designed in accordance with the invention is shown in Figures 4 and 5. Along the insulating path between electrodes 1 and 2, insulator 12 has a total of three different areas 13, 14, 15 areas 13 and 14 being wider than area 15. In this case, a line of flux 16 emerges from electrodes 1, 2 within insulator 12, and passes out of the insulator 12 at points VII
and VIII. In the case of a line of flux 17 which emerges from electrodes 1, 2 at the point where the contour of insulator 12 meets electrodes 1, 2, i.e. points B or A, it will be seen that this line of flux is at all times outside the insulator.
The same applies to line of flux 18. Although dirt upon the surface of electrode 1 or 2 may produce a discharge, but if this -discharge follows line of flux 17, it no longer impinges anywhere upon the insulator, and no sliding flash-over can occur. Thus the contour of insulator 4 shown in Fig. 4 is optimal. Even minor deviations from the contour shown in Figure 4 (see Figure 5) at worst result in the line of flux emerging from electrode 2 at point B and impinging upon the surface of the insulator at point IX, after passing for a considerable distance through the insulat-ing gas or liquid. Because of the long path of the line of flux through the gas or liquid, there is no longer any sliding dis-charge at point IX, and the advantage of the solution according to Figure 4 is therefore fully retained.
Figure 6 shows an insulator arrangement in which low-potential electrode 2 is of the same shape as electrode 2 in Figures 1 to 5, whereas electrode 25, which is at a higher potential, has an aerofoil-shaped cross-section selected merely at random. Insulator 26, located between electrodes 2 and 25 is designed in such a manner that a line of flux terminating at . ,.~ .
: .
. . ' . - ' ~' .'; ' :
0~7~3~ 7~3 points A and B at electrodes 2 and 25 does not penetrate the surface of the insulator at any location.
Figure 7 shows the perpendicular field strength along the interface in Figure 8, the said interface being marked 30.
Space 31, to the right of the said interface, is outside the insulator, whereas space 32 is inside the insulator. If the perpendicular field-strength pattern is followed along contour 30, the pattern shown in Figure 7 is obtained.
Now contour 30 is optimal if the integral of the perpendicular field strength along the development equals zero, i.e. if the area marked + in Figure 8 (and 33 in Fig. 7) is equal to the area below the abscissa, marXed 34 in Figure 7.
The configurational rule requiring that the insulator be designed in a manner such that the integral of the perpendicular field strength above the interface between the insulator and the surrounding SF6 gas be approximately zero, can be used only upon one condition. If insulator 3 in Figure 1 is considered, it will be observed that, even when there is a bulge in the middle, that is, ~hen the configuration is convex, the perpendicular field strength follows a similar pattern, as shown in Figure 7, but the sign is changed. Thus, if the configuration of the insulator is to be optimal, both rules must be observed simultaneously: on the one hand, the lines of flux must not enter the insulator (as in the case of insulator 12 in Figure 4) and, on the other hand, the integral of the perpendicular field strength over the interface ~
must bé approximately zero. This latter rule of configuration is ~-therefore only a klnd of ~'test" of whether the insulator is optimal.
. ' .
Claims (5)
1. An insulator, having two ends, for insulating electrodes at different potentials from each other and for supporting such electrodes, at either end thereof, in spaced relation to each other in surrounding insulating medium, the insulator having a surface extending over an insulating path between said two ends, characterized in that the insulator is provided with a narrowed zone between said two ends, the cross sectional view of which shows a substantially waist contoured form, said narrowed zone extending between the outer extremities of both said ends, said surface configuration being such that electric-flux lines extending between said electrodes and passing from electrode regions which are out-side the intersection of electrode and insulator surfaces, run for their entire length externally of said insulator.
2. An insulator according to claim 1, wherein the sur-face of the insulator along the insulating path is of a con-figuration such that the integral of perpendicular field strength, along an interface between the insulator and sur-rounding insulating medium is approximately zero.
3. An insulator according to claim 1 wherein the sur-rounding insulating medium is an insulating gas.
4. An insulator according to claims 1 or 2, wherein the surrounding insulating medium is an insulating liquid.
5. An insulator according to claim 3, wherein the insulating gas is SF6.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19752526668 DE2526668C2 (en) | 1975-06-14 | 1975-06-14 | insulator |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1078478A true CA1078478A (en) | 1980-05-27 |
Family
ID=5949131
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA254,633A Expired CA1078478A (en) | 1975-06-14 | 1976-06-11 | Insulator for electrodes inside an electrical switch gear |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS52351A (en) |
| CA (1) | CA1078478A (en) |
| CH (1) | CH598678A5 (en) |
| DE (1) | DE2526668C2 (en) |
| FR (1) | FR2314566A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4366340A (en) * | 1980-03-13 | 1982-12-28 | Ireq - Institut De Recherche De L'hydro-Quebec | Composite profile spacer for compressed gas insulated co-axial electrical cables |
| DE4007337C2 (en) * | 1990-03-08 | 1999-10-28 | Asea Brown Boveri | Electrical insulator |
-
1975
- 1975-06-14 DE DE19752526668 patent/DE2526668C2/en not_active Expired
-
1976
- 1976-06-08 CH CH717576A patent/CH598678A5/xx not_active IP Right Cessation
- 1976-06-10 JP JP51067197A patent/JPS52351A/en active Pending
- 1976-06-11 CA CA254,633A patent/CA1078478A/en not_active Expired
- 1976-06-11 FR FR7617694A patent/FR2314566A1/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| FR2314566A1 (en) | 1977-01-07 |
| JPS52351A (en) | 1977-01-05 |
| DE2526668A1 (en) | 1976-12-30 |
| DE2526668C2 (en) | 1982-11-25 |
| CH598678A5 (en) | 1978-05-12 |
| FR2314566B3 (en) | 1979-03-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA2502547C (en) | Highly insulated inductive data couplers | |
| US6353177B1 (en) | Vibration resistant overhead electrical cable | |
| EA199801055A1 (en) | ISOLATED CONDUCTOR FOR HIGH-VOLTAGE WINDOWS AND METHOD FOR ITS MANUFACTURE | |
| US3324272A (en) | Termination of insulators | |
| US3287489A (en) | Insulated high voltage cables | |
| CA1078478A (en) | Insulator for electrodes inside an electrical switch gear | |
| BR9702635A (en) | Electromagnetic equipment | |
| KR100309318B1 (en) | Electromagnetic Interference Heating Cable | |
| ATE205958T1 (en) | WIRE BUNDLE FOR ELECTRICAL SIGNALS | |
| EP0798950B1 (en) | High voltage noise filter and magnetron device using it | |
| KR910007256A (en) | Line filter | |
| ATE344971T1 (en) | INSULATOR FOR ELECTRICAL CONDUCTORS WITH EXTERNAL SHIELDING. | |
| BR9807149A (en) | Transformer or inductor winding | |
| US4517405A (en) | Compact conductor device | |
| JPS605747A (en) | Insulated coil | |
| JPH03222621A (en) | Gas-insulated spacer | |
| JPS6224910Y2 (en) | ||
| DE59601727D1 (en) | WINDING ELEMENT FOR AN ELECTRICAL MACHINE | |
| ATE224114T1 (en) | INSULATED CONDUCTOR FOR HIGH VOLTAGE MACHINE WINDINGS | |
| SU1647663A1 (en) | Lead-through insulator for explosion -proof electric equipment | |
| JP3657890B2 (en) | Gas insulated switchgear | |
| SU636686A1 (en) | Pass-through insulator | |
| ATE183030T1 (en) | ENCAPSULATED ELECTRICAL DEVICES PROTECTED AGAINST SURGE VOLTAGE | |
| SE9901985L (en) | Switchgear | |
| ATE261179T1 (en) | FEEDTHROUGH INSULATOR WITH ELECTRICAL FIELD SHIELDING, ESPECIALLY FOR MEDIUM AND HIGH VOLTAGE SWITCHGEAR |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |