DE1088568B - Rod-shaped high-voltage insulator with points of different conductivity, preferably made of cast resin - Google Patents

Description

The invention relates to rod-shaped high-voltage insulators with points of different conductivity, preferably on high voltage insulators made of cast resin. As soon as foreign layers build up on their surface, these are high-voltage insulators, particularly when these foreign layers become damp, exposed to a reduction in insulation. In this case, the insulators are already at relatively low voltages along their surface overturn.

According to the invention, this disadvantage is avoided in that the surface current is interrupted the insulating body alternately transversely to the axis in sections with higher and lower insulating properties is divided, which is preferably provided only in the area of the surface of the insulating body are.

In the case of high-voltage insulators with ribs or shields, there are parts with a larger diameter of the insulator, such as B. the ribs or screens, wholly or partially made of an insulating material of lower insulating capacity and the parts of smaller diameter of the insulating body, so z. B. the shaft, made of insulating material greater insulating capacity.

The parts with lower insulating properties cannot only be found in the border area of the surface of the insulating body be provided, but extend more or less into the interior of the insulator body or also form entire continuous layers of the insulator body. In this case it is the insulator body made up of alternating layers with high and low insulating properties. They are already insulating bodies known, which is made up of powdery insulating and electrically conductive layers of material which are solidified by pressing and sintering and thus have points of different conductivity. The purpose of this measure in the known insulating bodies is to reduce the electrical conductivity in the Constantly changing the insulating body and thus influencing the electrical stress on the insulator. In the case of the known, however, the problem underlying the invention is not the interruption of the Surface current and its distribution on certain creepage distances ani insulator raised and solved.

The materials used are normal and normal insulating materials for the layer with high insulating properties Insulation materials with additives made of semiconductor substances for the parts with a lower insulating capacity. Leaning agents can also be used in both parts.

Details of the invention are shown in some exemplary embodiments with reference to the drawing in FIG Fig. 1 to 4 explained.

Rod-shaped high-voltage insulator

with points of different conductivity,

preferably made of cast resin

Applicant:

Siemens-Schuckertwerke

Corporation,

Berlin and Erlangen,

Erlangen, Werner-von-Siemens-Str. 50

Dipl.-Ing. Hans v. Cron, Berlin-Siemensstadt,
has been named as the inventor

The drawing shows a schematic, very greatly enlarged view and partially in Section five exemplary embodiments. All figures represent long rod insulators, but the invention is not limited to rod insulators.

In Fig. 1, a long rod insulator with projections is shown in section, the one layer lower Has insulating property on the surface of the protrusions;

Fig. 2 shows a long rod insulator, in which all the projections made of a material with less Insulate;

Fig. 3 illustrates a long rod insulator which is made up of alternating continuous layers with high and low insulation properties;

4 shows an example of a solid core on the left and an example of one on the right Hollow insulator.

According to FIG. 1, the insulator consists of the core 1, the projections 2 and layers 3 arranged on them and having a lower insulating capacity. The foreign layer is denoted by 4. Line 5 indicates the leakage current curve. At the points 6, the current branches into the branch 7 in the foreign layer 4 and into the branch 8 in the layer 3 with a lower insulating capacity. In FIG. 2, the insulator shaft 1 has projections 9 made of material with a lower insulating capacity. The leakage current will flow approximately on the paths indicated by the line 10 and the branches 10 a, 10 & and 10 c. According to FIG. 3, the insulator consists of layers 11 and 12, which extend over its entire cross section and are arranged alternately one above the other

009 590/285

which the layers 11 made of cast resin, for. B. araldite with a semiconductor surcharge of silicon carbide, the layers 12, however, consist of araldite with about 250% Ouarzmehlzuschlag. With 4 the foreign layer is again referred to. The semiconductor surcharge is dosed in such a way that it is not the wet, but the dry insulator that has the required breakdown voltage. The lines 14a and 15a to 15e are intended to show that through the foreign layer 4 only a small part 14a of the leakage current 14, through the projection

11 α and the core part of the layer 11, on the other hand, almost all of the leakage current flows.

Fig. 4 shows two further embodiments of isolators according to the invention partially in Cut. The left half represents a solid core insulator and the right half a hollow insulator. The The direction of the leakage path corresponds to the axial direction of the insulator for all insulators, in this case direction 16, 17. The division of the insulator body into slices

12 with high insulation capacity and in panes 11 with lower insulation capacity is also here perpendicular to the isolator axis, i.e. H. perpendicular to the main direction of the creepage distance carried out.

The use of Siliciumkarbi'd as a semiconductor has the advantage that due to the voltage dependence this resistance causes an increasing stress concentration on the protrusions below the effect of surface foreign layers is prevented.

Equivalent materials can be used in place of the specified insulating, semi-conductor and lean substances will. Porcelain bodies can also be used for the casting resin with various additives or Kunstharzpreß materials or glass with appropriate additions of semiconductor substances and lean substances use to build the isolators. So you can z. B. as semiconductor materials also semiconductors use rutile-based or hematite semiconductors. Also ferrites with a spinel crystal structure according to the general formula M Fe 204, in which M is a metal known for this purpose, can be considered.

One can subdivide the creepage distance by changing the number of projections more or design less finely.

The illustrated shapes of the insulating body are only exemplary embodiments. One can make the invention z. B. also apply to all types of shield insulators and helical insulators.

The invention causes an extreme distortion of the current and voltage ratios at individual Surface spots of the insulator are prevented by having a more or less finely graduated distribution the voltage and the current. Those preferably consisting of resin and semiconductor substance namely, protruding parts of the insulator, the ribs or shields form as semiconducting layers Shunts to the protruding parts of the creepage path, thereby preventing pre-discharges and flashovers over the projections, at the same time they act as stabilizing resistors for the shafts of the Creepage distance, d. H. i.e. for parts with a small creepage distance and high current density. Hence it arises a split pre-discharge on the dirty and damp insulator, which is a number of stabilized ones Glow discharges of low current density with increasing current-voltage characteristic between the There are projections. This interrupts the flow of leakage current and prevents flashover.

Claims (9)

Patent claims: 1. Rod-shaped high-voltage insulator with points of different conductivity, preferably made of cast resin, characterized in that the insulating body is used to interrupt the surface current alternately across the axis in sections with higher and lower insulation properties is divided, which are preferably provided only in the area of the surface of the insulating body. 2. High-voltage insulator according to claim 1 with ribs or screens, characterized in that that the parts of larger diameter of the insulating body, such. B. the ribs or screens, whole or partly from an insulating material with a lower insulating capacity and the parts with a smaller diameter the insulating body, e.g. B. the shaft, consists of insulating material greater insulating capacity. 3. High-voltage insulator according to claim 1, characterized in that the insulating material with a lower insulating capacity also into the interior of the part of the larger diameter of the insulating body extends. 4. High-voltage insulator according to claim 1 when made of cast resin, characterized in that that the insulator body consists of alternating layers of the casting resin, preferably ethoxylin resin, is constructed with two types of aggregates, one of which is a semiconductor substance and the other is an insulating substance. 5. High-voltage insulator according to claim 4, characterized in that the semiconducting substances have a voltage-dependent resistance. 6. High-voltage insulator according to claim 5, characterized in that the semiconductor substance Silicon carbide is used. 7. High-voltage insulator according to claim 5, characterized in that a semiconductor substance is used on a rutile basis. 8. High-voltage insulator according to claim 5, characterized in that the semiconductor substance Hematite semiconductors are used. 9. High-voltage insulator according to claim 5, characterized in that the semiconductor substance Ferrites with spinel crystal structure are used. Considered publications: German Patent Nos. 355 248, 703 056; U.S. Patents Nos. 2,371,660, 2,239,809,
522, 1735 829; Swiss patents No. 246 094,
307111; British Patent No. 564669; Journal »Kunststoffe«, year 1953, issue 10, p. 390, figs. 5 and 6, and p. 387. 1 sheet of drawings © 009 590/285 8.60