DE1045502B - Electric outdoor rod insulator - Google Patents

Description

GERMAN

The invention relates to an electrical outdoor rod insulator, the shaft part evenly over its Has length distributed, with drawn down rounded drip edges provided with umbrellas.

As the operating voltage increases, the interference on overhead line insulators increases caused that foreign layers are deposited on the insulators, which the breakdown voltage reduce considerably. These foreign layers include deposits of all kinds, such as soot, coal, dust, Salt, cement, metallic deposits, etc., which are partly due to their own conductivity, partly in connection with Moisture the breakdown voltage to a fraction of the breakdown voltage of clean insulators reduce. The reduction of the flashover voltage is particularly strong in fog and dew, whereby the entire insulator surface is covered with a film of moisture, so that even far sweeping rain protection roofs are ineffective.

Attempts have already been made to counteract these difficulties by using special insulator shapes by "self-cleaning" insulators were produced in which rain and wind brush large areas of the insulators and make the precipitation of foreign layers more difficult or wash it off when it rains can. But even this measure is not very effective if after a long period of drought heavy fog and dew occur without the foreign layers being washed off by previous rain became. In addition, the well-known constructions of the "self-cleaning" isolators require a Significant enlargement of the external dimensions if the creepage distance, which is important for the flashover voltage of dirty insulators, is important plays, wants to keep it as large as possible.

In any case, care must be taken that the foreign layers, no matter what kind, in particular a skin of water that forms as a result of fog or dew, not a coherent one uniform conductive layer on the insulator surface and thus one of the two insulator fittings can form connecting creepage path for electrical discharges.

Post insulators with several rain umbrellas arranged one above the other have already become known. in which the rounded drip-edge umbrellas on their Undersides have circumferential groove-like depressions that are rounded with a very small radius, thus have delimiting edges in the form of ribs that can be designated as "sharp".

However, the sharp edges only lie on the underside of the screens and are essentially also directed downwards only; they are supposed to

Electric outdoor rod insulator

Applicant:

Rhenish-Westphalian

Isolatoren-Werke G.m.b.H.,

Siegburg (RhId.), Industriestr. 4-10

Dr.-Ing. habil. Kurt Draeger, Siegburg (RhId.),
has been named as the inventor

If necessary, distribute precipitating moisture better. The ones with rounded drip edges Rain umbrellas are designed in such a way that the upper umbrellas each have a larger diameter than the umbrellas underneath them, so that they are not connected even in heavy rain Water jets can form, the direct rollover between the drip edges of the Umbrellas surrender.

However, the effect of the sharp edges below the umbrellas is slight. You can at most contribute to the fact that moisture deposits occur on the surface of the insulator Discharges quickly detach themselves from the insulator body as arcs and advance to the screen edges, where they combine to form an undesirable total rollover. This will be especially true be the case if there are slightly soiled areas due to the ribs under the umbrella, which also dry out relatively quickly and overflow from the partial arcs that initially form whose base points are at the edges of the still damp covering of the umbrellas to the front or to the outside hike.

Furthermore, it is no longer new to have high-voltage insulators intended for gas cleaning systems, to be provided with sharp-edged, circumferential ribs in larger numbers and these sharp-edged ribs if necessary to be designed as conductive electrodes. These sharp-edged ribs are in a certain way Distance corresponding outer electrodes juxtaposed to the sharp edges of the insulator body generate high electric field concentrations that cause the formation of moisture deposits on the insulator itself as well as any accumulation of moisture in the vicinity of the To prevent isolators.

809 '697/419

However, these isolators are - in accordance with their intended use - in rain-protected rooms housed, so that the task of the sharp-edged ribs in connection with the counter electrodes only consists in keeping the humidity away from the isolators.

In contrast, the rod insulator according to the present invention is an outspoken one Outdoor insulator that ensures sufficient flashover voltage in heavy rain as well as in dusty and humid air have a flashover voltage of sufficient height should be provided without special counter electrodes.

These two requirements are not simultaneously more satisfactory from the previously known isolators Way fulfilled. The usual rod, especially long rod insulators with a greater distance screens arranged on the shaft from one another, the drip edges of which are rounded, have at clean insulator surface a relatively high rain flashover voltage; However, the flashover voltage is already largely due to the precipitation of dust and moisture on the smooth insulator surfaces reduced if insufficient »cleaning« is carried out by rain and wind.

The insulators already mentioned above, only intended for interiors, with numerous sharp, circumferential insulators Edges on which - with the help of special counter electrodes - dust and moisture deposits largely prevented, result in dryness in dusty air or also in strong fog, relatively high flashover voltages; however, if they are used as outdoor insulators, see above However, in the event of heavy rain, they can move between the closely spaced ones on top of each other sharp-edged ribs form contiguous water jets that form a direct connection and thus can lead to a direct flashover between the two armatures of the isolator.

The invention is based on the idea that sharp-edged ribs or grooves on the insulator circumference not only provided on the underside of the umbrella with rounded drip edges should be, but also in those places where these sharp-edged ribs or sharp outer edges of circumferential trough-shaped grooves washed off by rain and thus additionally getting cleaned. You should also be such that the sharp edges approximately perpendicular to the electrical Field lines stand and thereby electrostatic effects occur, which repel Moisture in the area of the sharp edges.

The invention thus has an electrical outdoor rod insulator as an object, the shaft part with Evenly distributed over its length, having drawn down, rounded drip edges Rain umbrellas is provided, in which, according to the invention, on the shaft part of the insulator between the umbrella and / or additional umbrellas on top of the umbrella sharp outer edges or circumferential protruding ribs or trough-shaped grooves with sharp-edged Boundary lines are provided, the outer diameter of which is smaller than the outer diameter of the Umbrellas.

Only the combination according to the invention of the drip edges sitting on the outer edge of the umbrella with the sharp edges further inside on the shaft part and / or on the top of the rain umbrellas arranged ribs or grooves or special additional umbrellas with sharp outer edges bring a solution to the aforementioned problem.

By their arrangement on the shaft part and possibly Even on the top of the umbrellas, the sharp edges are the inclined ones Immediately exposed to water droplets. Quite apart from the fact that the external

ίο less dirt can be deposited on the sharp edges of the insulator becomes a part this dirt is washed off again by the rain, and from the remaining layer the water-soluble, electrically conductive particles will largely dissolve out.

The large number of sharp-edged ribs or grooves on the perimeter of the insulator makes a very good result long creepage distance, which has a favorable current-limiting effect. Because the sharp edges of the grooves or ribs are directed essentially outward, the conductive impurity layer also becomes Tear lightly around the grooves or ribs. There are thus low-current discharges arise not only on the shaft of the insulator between the rain umbrellas, but also in each case on the sharp edges of the ribs or grooves, between which there may be damp foreign layer zones are located.

This large number of low-current discharges, which are connected electrically in series, has an effect now has a favorable effect on the dielectric strength of the insulator.

Each of the partial discharges represents with its cathode fall, the discharge column and the anode case represent a considerable resistance, so that longitudinal the entire surface of the insulator is very weak, even under unfavorable operating conditions Can form leakage currents. At these low currents it is unlikely that the initially occurring - in the present case quite desirable - low-current discharges with increasing Voltage characteristic in the undesirable high-current arc discharges with falling Change the characteristic and thus initiate a total rollover.

To clean the depressions between the sharp edges by wind and To facilitate rain, the depressions should be rounded at their base.

Furthermore, it has proven to be useful in and of itself to achieve a high level of rollover security as is known, the entire insulator surface or at least individual parts of this surface to be provided with a water-repellent glaze or with appropriate lacquers.

In the drawing, the invention is illustrated on a rod insulator of greater length; it shows and half in view, half in section,

Fig. 1 shows an outdoor long rod insulator according to the invention, which except for the evenly over his Length distributed, with rounded, rounded drip edges provided with rain protection umbrellas on its shaft part and on the top of the umbrellas sharp-edged circumferential ribs or Has grooves,

Fig. 2 shows a part of an outdoor rod insulator according to the invention, in which between the rain umbrellas further umbrellas with sharp outer

Edges are arranged, the diameter of which is smaller than the diameter of the rounded drip edges provided umbrellas.

The long rod insulator 1 shown in Fig. 1 is provided with clapper fittings 2, 2 ' which are cemented onto the somewhat thickened head ends 3, 3' of the insulator shaft with putty 4, 4 '. In the fittings 2, 2 ' , the clapper 5, 5' are suspended. Protective umbrellas 6, which are distributed evenly over its length and are provided with rounded drip edges 10 drawn down, are seated on the insulator body. The diameter of the rain umbrellas 6 is larger than the diameter of the fittings 2, 2 '.

On the insulator surface of the shaft part are between the rain umbrellas 6 and on the Top of these screens sharp-edged elevations 7 in the form of ribs and also trough-shaped Grooves 8 provided with sharp-edged boundary lines, the outer diameter of the sharp circumferential edges is smaller than the outer diameter of the rain umbrellas 6.

The recesses lying between the protruding ribs and the groove edges are on theirs The base is rounded to allow the grooves to be cleaned by wind and rain.

The embodiment according to FIG. 2 shows an insulator design in which the sharp-edged ribs 7 as additional umbrellas are only arranged between two umbrellas 6 on the shaft part of the insulator are.

In the event of heavy rain, which is indicated by lines 11 in FIG. 2, the formation of coherent water jets along the insulator body 1 and thus the occurrence of current bridges between the fittings 2, 2 'is avoided with this insulator, since the rounded drip edges 10 the rain umbrellas 2 dripping raindrops 12 on the sharp edges 7 - partly as a result of the electrostatic effect "- spray.

Claims (3)

PATENT CLAIMS: 1. Electrical outdoor rod insulator, the shaft part with rain umbrellas evenly distributed over its length, which have rounded drip edges pulled down, characterized in that on the shaft part between the rain umbrellas and / or on the top of the umbrellas additional umbrellas with sharp ¹ outer edges or circumferential protruding ribs or trough-shaped grooves with sharp-edged boundary lines are provided, the outer diameter of which is smaller than the outer diameter of the umbrella. 2. Isolator according to claim 1, characterized in that between the above Ribs and the groove edges lying recesses are rounded at their bottom. 3. Isolator according to claims 1 and 2, characterized in that the entire insulator surface or individual parts of this surface in a known manner with water-repellent Glaze or covered with appropriate varnishes. Considered publications:
British Patent Nos. 18,586 of 1903, 214 170; German patent specification No. 843 561. 1 sheet of drawings © Ä09 ^! 697ft19 <11.58