DE8300737U1 - Cast resin insulator for high voltage cable terminations - Google Patents

Description

Pl 4674 1 01/12/83

Cast resin insulator for high voltage cable terminations

The invention relates to a cast resin insulator for high-voltage cable terminations with a central cylindrical bore and a coaxial funnel-shaped field control electrode. It can be used with different cable types and dimensions, and offers at least the same good field control as with the more complex isolators with capacitive field control inserts and is easy to manufacture.

Cast resin insulators of the type mentioned have long been known, for example from US Pat. No. 2,945,913. The insulator there has the shape of a club, the diameter of which decreases towards the base (i.e. the cable). There is a field control funnel in the insulating lobe Poured in conductive material, which is led out of the lobe at the foot and there with the cable shield is electrically connected. This termination is prefabricated and pushed onto the cable. Because the material is inelastic the inner hole must be slightly larger than the diameter of the cable core, and the annular gap between them must be be filled with a solid or liquid insulating material after being pushed on.

So this Gießnarzisolator has the disadvantage that it only at a certain cable dimension can be used. He also lacks equipment with a foot arm and a head arm. so that the end closure is not at the same time a supporter

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Fl 4674 ·· ■ '" 2 ' 01/12/83

works. These terminations are mounted with the Pussarmatur on an end closure frame, whereby a lateral The action of force avoids kinking of the termination and the cable will.

Cast resin insulators for high-voltage cable end connections are also known which contain capacitive field control inserts, for example from DE-GM 1 777 892. The insulator there has the shape of a pear, the largest diameter of which is close to the base. In the insulator, overlapping, coaxial copper rings are cast at intervals, which act as capacitive field control inserts. The production of a ^v such insulator requires some effort. In addition, he is also lacking training as a supporter.

Now the combination has already been trained as a supporter End closure proposed with a cast resin insulator, which has both field control inserts and a field control funnel contains (DE-P 32 10 563). This end closure can be used universally because its inner bore widens in the foot area is and here a hollow cylindrical adapter from one elastomeric insulating material is inserted, the inner diameter of which depending on the application (diameter of the cable shield) is chosen. If you choose the material of the adapter with a ^ higher dielectric constant than that of the insulating lobe, in this way, a so-called refractive field control is obtained for the electrical load (see book by Klockhaus and Wanser "Termination and connection technology for power cables", Verlag VWEW (1979) pp. 45-46).

Finally, as far as the field control funnel is concerned, it has been known for a long time to apply it to the foot of the club instead of inserting it into the club. This is done simply by means of a 1ei t capable varnish or casting resin . More recently, it has moved to give the shape of a so-called Borda-profile hopper, which has the advantage,

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that the field strength curve remains constant over the entire edge contour and thus the edge zone is not subjected to more electrical stress than the homogeneous area, and that the edge area takes up less space than with other profiles (see book by Prinz "Hochspannungsfelder ¹¹ , Verlag R. Oldenbourg Munich and Vienna (1969), pp. 196-209).

Based on the prior art mentioned at the outset, the invention is based on the object of providing a cast resin insulator for To create high-voltage cable terminations that can be designed as a support and can be used universally, an optimal field control and is simple in construction and manufacture.

According to the invention, this object is achieved by the characterizing features of claim 1. The solution lies essentially in the fact that the insulator has a larger diameter in the lower half than at the top, and that it widened at the bottom Has an inner bore into which an adapter made of elastomeric insulating material is inserted, and that the insulator has a bottom Has ring recess which is designed according to a Borda profile and has a conductive coating.

The isolator according to the invention has the advantages that it is universal can be used and that the insertion of the capacitive field control elements can be dispensed with, whereby the production of the isolator is considerably simplified. In addition, the application of elastomeric screens and the attachment of foot and Head fitting according to the usual type - to complete the isolator to the end closure acting as a support - easy here possible.

The subclaims relate to the shape of the field control electrode, the material and the shape of the adapter and the application of the insulator screens.

Fl 4674

1/12/83

An embodiment of the invention is shown in the drawing and is described below. There the cast resin insulator is shown with an adapter that connects a cable core from slightly smaller diameter than the inner bore of the insulator. In addition, the completion to the end closure is with Silicone rubber shields, foot and head fittings and the connection of a cable entry funnel at the insulator base.

Are marked with

1 cast resin insulator

2 Insulator thickening in the foot area

3 inner hole

4 Expansion of the inner bore

5 ring recess

6 adapters made of elastomeric insulating material

7 FeI ^ control electrode (conductive coating)

8 insulator foot inside

9 Borda profile upper edge

10 Insulator foot outside

11 Screw connection for cable entry funnel

12 silicone rubber umbrellas

13 foot fitting

14 head fitting

21 Cable shield

22 Cable insulation

23 cable ladder

24 Connection of cable shield with field control funnel

This is the inventive design of the Gießharzisolatorb not difficult to see from the drawing. The material chosen for the insulator (more precisely the insulating lobe) is preferred Epoxy resin.

If you want to bring in the additional advantage of a refractive field control (see above), you choose the insulating material of the adapter with a dielectric constant 5-10 times higher than that of

Pl 4674 »· '"' V '^;<"" 12.01

Insulator, for example an ethylene-propylene rubber with i " _r = 30 against 4.5 in the case of epoxy resin. If you choose the insulating material of the adapter with approximately the same dielectric constant as the insulator, it is advantageous to make the base area of the adapter funnel-shaped and with it to be provided with a conductive coating (see DE-P 32 10 563),

Claims (1)

Fl 4674 1 01/12/83 Expectations: 1. Cast resin insulator for high voltage cable terminations with a central cylindrical bore and one for this purpose coaxial funnel-shaped field control electrode, characterized in that a) the insulator (1) in the foot area with "a radial thickening (2), with an extension (4) of the central bore (3) open towards the foot end and in the radial one Distance here from is formed with a coaxial ring recess (5) which is also open at the end, b) the bore widening (4) cylindrical or light is conical and therein a hollow cylindrical adapter piece (6) made of an elastomeric insulating material is exchangeable, but inserted without a gap, c) on the surface of the ring recess (5) one electrically conductive layer is applied as a field control electrode (7), which extends from the inner insulator base (8) funnel-shaped to the outer upper ring recess (9), the recess and electrode having the same shape a Borda profile. 2. Isolator according to claim 1, characterized in that that the annular recess (5) is completely covered with an electrically conductive coating (7). Pl 4674 1/12/83 Insulator according to Claim 1 or 2, characterized in that that the adapter (6) made of an insulating material with a 5-10 times higher dielectric constant than with the isolator (1) (refractive field control). Insulator according to claim 1 or 2, characterized in that the adapter (6) consists of an insulating material with approximately the same dielectric constant as the insulator (1), and its foot area is funnel-shaped and provided with a conductive coating. ■■. Insulator according to one of claims 1 to 4, characterized in that ds * 3 its outer surface between The foot and head fittings are completely covered with radially protruding elastomeric shields (12), which are known per se is.