DE1665324A1 - Product for impregnating high voltage cables and cables made with them - Google Patents

Description

Product for impregnating high-voltage cables and cables made with them

(Additional application to German patent application P 22 822 VIIId / 21c

from the 22nd shark 1959)

The invention relates to a product for the impregnation of electrical (| see high-voltage cables of the so-called "oil-filled" type and cables impregnated with this product.

This project is included in the patent specification "» «> ..s (patent * aameldtt?>. G P 22 82g YXIM / 21 s), because it consists of iXlqaJhBnmQltri with, © iaea Molecular weighted Im la ^ aish of 200 bie i & ^ vai.mi «au cUi ^; - dia Λίΰ-igsi ^ .ag einar ©" .loflfiiivj ^} wn? er «

BATH ORIGINAL

tin synthesis process obtained. Ea is known, the β one so far Has used liquid mineral oils to impregnate oil cables; however, such mineral oils show limited gas absorption water electrical loads, decreased resistance under thermal loads, they can deposit guard at very low temperatures and show their natural Origin according to »an uneven chemical structure and thus a corresponding fluctuation in its chemico-physical Properties.

The use of alkylbenzenes as impregnation compounds, for electrical cables and especially the use of dodeoyl

benzene, which is used in large measure for the manufacture of detergents is produced by synthetic means, is in the German patent (patent application P 22 822 VIIId / 21 p)

described which in contrast to other further patents describes the use of dodeoylbenzene as a solohem and not as an additive to mineral oil in various percentages »

These alkylbenzenes which substances a well-defined chemical composition daj * stenen _f besltr> ati # 3 * IOSS permanent ch * - ei "ah- <pliYfdkalIsche Wi ^ tne ^ haf i * ■ *" * .Xa ΙιαρΓί * ^ n, \ vmi ti>, % .for

BAD ORiQINAL

haggle loads and sine higher heat resistance! differ over it do not watch at low temperatures.

The aim of the present invention is to provide an impregnating agent for High-voltage cables already have parts made from other alkylbenzenes is formed as the dodecylbenzene and by the Tav aache is characterized by a very low Viecoaltät *

The aim of the invention is a product for impregnating Hoohepan

voltage cables according to the patent specification (patent application

P 22 822 YIIId / 21 c), which consists of one or more alkylbenzenes consists «in which the aliphatic chain (both linear as well as branched) contains 9 to 11 carbon atoms and welohea a variety in the range of 2 to 10 cSt (Centlstokee) and a Harcueaon flash point (open shell) ron above 100 ° 0.

The alkylbenzenes of the present invention are the Honyl, Deoyl and Uhdecylbenol «each of them - like the Dodeoylbenol of the parent patent - not necessarily as an individual ohemisoher constituent must be considered “but a mixture of isomers and homologues can exist” which there Durohschnittliohe Holekulargewloht dee nonyl-, decyl- or undecylbenzenes own.

109812/1358 '^ _{0 Shark (IAL}

ί:> zeift d3i product containing a-js a mixture of isomers and I τηοΐοββη oiateht whose average molecular weight corresponds to t £ 04) that ies Nonj / Tbenssolii and its latte aliphatic "has a rarzweigte St ^ -uktur, a Viscostität of < , 8 o8t at 20 ° O, of 2.4 cSt at 50 ° C and a flash point ! open Sohale) of 115 ° C

The product with an average molecular weight (218), which corresponds to deylbenzene and has a branched aliphatic-Bche chain, shows a viscosity of 5.7 oSt at 20 ° C, of 2.7 cSt at 50 ° C and a flash point of 117 ° O ₀

The product with an average molecular weight (232), which corresponds to undecylbenzene and a branched allphatieche Chain has a viscosity of 6.9 cSt 20 ° 0, of 3 cSt at 50 ° C and a flash point of 125 ° C

If the branched chain alkylbenzenes are already used for impregnation electrical cable and cheap, then alkylbenzenes are with linear chain is even more advantageous because it has the same viability have a higher flash point (open Sohale) or, with the same flash point, a lower viecoedtät.

It has been found experimentally that although the flash point of these alkylbenzenes is significantly lower than that of dodecyl

-4- 109812/1358

BATH

benzene (155 ° 0) and even more than that of liquid mineral oils (155 ° to 160 ° C), he is far enough in all respects to To prevent the risk of fire, provided that the connection i.rd Laying work of such cables, which with this product are impregnated, must be carried out with the necessary care.

In comparison with dodecylbenzenes, these alkylbenzenes have a Vi se ο si did such low that it took a very long time to manufacture Oil cables, for example underwater cables, allow without the Necessity of intermediate fillings by means of expansion cups.

This fact can be explained from the knowledge of the mechanism of action of oil cables. It is known to be a static Pressure is uniformly transferred to the entire cable system such a pressure must reach a sufficient value, since during the thermal cycles to which the cable is subjected, and especially during the cooling phase along the oil channel, a higher internal pressure than the external at any moment Pressure acting on the envelope can be present.

When the cable is cooled down, the amount of impregnation, liquid so that an equal volume of the loaded ends of the cables has to be drawn in, Cao out? this way ,, - ':?' βγΐ2 ^ liesBon d'ü * Iur ^ gn ^ erfiitsotgkeU; hewirkfc »inen

3λ it is clear that from a construction point of view, the Xabsluiso is simpler, the lower the required feed pressure, and the lower the lower the viscosity of the impregnation liquid, the lower this pressure is.

The invention also relates to a high voltage electrical cable of the so-called oil-filled type, which is suitable for both Weohselatros as well as especially suitable for direct current 1st and the old the product described is impregnated.

An example is given below showing the advantage of the Use of very low viscosity alkylbenzene instead of dodecylbenzene and of liquid mineral oil.

An underwater cable of the so-called oil-filled type with a Length of 20 km requires a beechiokung print at both ends of 13 kg / cm when it is with deoxybenzene with a Visoosltät of 5.7 cSt is impregnated at 20 ° C.

The same cable, loaded at both ends with dodecylbenzene with a viscosity of 12.5 cSt at 20 ° 0, would require a pressure of 31.2 kg / cm (this is 2.4 times the value given above). That g :: eiche cable, which with its original size, is currently on the market "b <3 ^f 'lndlohen mineral oils of the eii .'.- ai-lgei-ΐϊα VluoüiiiUii; _; <orüUc wi -rl ■ -,; {<'iJ al a » niederviiooa» ■■ t -' J. 'itrdu «iiitifL bvx, ■> 4 n \,' u ί ',:.' t.rt: t learn (gl «ioh & ■ ^Λ

ι U ■■■■ 'ι J- ": ^' * BATH

ϊ> 76 h

2, iaohen Λν.β very specified '/ er * β) and filled with a mineral31 of the type, which was generally in use in the last few years:?, A pressure of 68.9 kg / cm would be required be. 'equal to 5t3 times the first listed value); from this it is easy to see that this pressure cannot be achieved in the last-mentioned pail and would result in a difficult and expensive implementation in the second and third of the cases mentioned.

- 7 - 109812/1358

■> W2 ^ M-

Claims (1)

2 «£ 76 30 March 1966 Godfather is. ta η s ρ rü ch e 1, Prodv.it ssma impregnation of high-quality electrical cables, characterized in that it consists of one or more alkylbenzenes in which the both branched as well as linear aliphatic lettuce 9 to 11 carbon atoms and a viscosity in the range of 2 to 10 cSt at 20 ° C and a Marcussön flash point (open shell) above 100 ° C. 2 _e high-voltage electrical oil for alternating current and in particular for direct current, characterized in that it is impregnated with the product according to example 1. 109812/1358 BAD 0R! 3iNAL