EP3656039A1

EP3656039A1 - Electric insulation material and/or impregnation resin for a wrapping tape insulation for a medium- and/or high-voltage machine, and insulation system made thereof

Info

Publication number: EP3656039A1
Application number: EP18779235.3A
Authority: EP
Inventors: Jürgen Huber; Steffen Lang; Niels Müller; Michael Nagel; Matthias ÜBLER
Original assignee: Siemens AG
Current assignee: Innomotics GmbH
Priority date: 2017-09-20
Filing date: 2018-09-13
Publication date: 2020-05-27
Also published as: EP3460959A1; US20210376681A1; WO2019057601A1; CN111133661A; CN111133661B

Abstract

The invention relates to an electric insulation material and/or impregnation resin for a wrapping tape insulation and to an insulation system, for example an insulation system for a rotating electric machine, in particular a medium- or high-voltage machine. By means of the invention, an insulation material and/or an impregnation resin for a wrapping tape insulation is first provided, said material and/or resin exhibiting a substantially increased partial discharge resistance in the presence of compounds which form a SiR₂-O- backbone in the cured resin. Thus, the thickness of the insulation system can be drastically reduced, i.e. by up to 20% for example.

Description

description

Electrical insulation material and / or impregnating resin for the winding tape insulation of a medium and / or high voltage machine and an insulation system thereof

The invention relates to an electrical insulation material and / or impregnating resin for the winding tape insulation and an insulation system, for example an insulation system for a rotating electrical machine, in particular a ^¬ tel or high voltage machine.

To generate electrical energy typically rotating high-voltage machines are used in the form of generators. EP 1 981 150 A2 describes a generator with a rotatable rotor and a stator arranged around the rotor. The stator has a rotationally symmetrically configured laminated core, wherein electrically conductive winding rods run in grooves on the laminated core. At the Blechpa ^¬ ket is followed on both sides by a winding head, which connects the winding rods via connecting webs to a closed winding. When operating high-voltage machines with outputs of more than 500 MVA, rated voltages of more than 10 kV can be achieved. The components are exposed to correspondingly high mechanical, thermal and electrical loads. The reliability of the insulation system of the electrical conductors is therefore relevant for the operational safety responsible ^¬ Lich.

An insulation system has the task electrical conductors, such as wires, coils and winding rods, permanently against each other and against the laminated core of the stator or to isolate the environment. For this purpose, the insulation system has an insulation between partial conductors (partial conductor insulation), between the conductors or winding bars (conductor or winding insulation). tion) and between the conductors and the ground potential in the slot and winding head area (main insulation).

The fundamental problem with such electrically loaded insulation lies in the partial discharge-induced erosion with forming "teering" channels, which ultimately lead to the electrical breakdown of the insulation.Usually mica-based insulation is used for permanent insulation of the live conductors in rotating machines.

To form the main insulation, the preformed coils made of insulated partial conductors are wrapped with mica tapes and impregnated with a resin as part of a vacuum pressure impregnation (VPI process). Mica tapes are used in the form of mica paper.

As a result of the impregnation, the cavities in the mica paper between the individual particles and / or strip folds are filled with the insulating material. The composite of impregnating resin and mica paper is hardened, forming the insulating material, which is then processed in the insulation system and provides the mechanical strength of the insulation system. The electrical strength results from the many ^¬ number of solid-solid interfaces of the mica inn. The VPI process therefore requires even the smallest cavities in the insulation to be filled with resin to minimize the number of internal gas-solid interfaces.

All in all, this places the highest electrical, thermal and mechanical demands on the insulation of the conductors of a winding with one another, the winding against the laminated core as well as the sliding arrangement formed at the outlet of the conductors from the laminated core. In machine insulation, a distinction is made between the internal potential control IPS between the copper conductor assembly and the high-voltage insulation, the external corona shielding (AGS), between the winding and the sheet metal foil. ket, as well as the Endeglimmschutz (EGS) at the exit of the winding bars from the laminated core.

A conventional insulation system, an impregnated winding of mica tape with tape adhesive and tape accelerator, a base resin, for example an epoxy resin and one or more hardeners, optionally also epoxy-functionalized hardener, is in the range of 0.5 to 6 mm thick. During operation of the electrically rotating machine, electrical discharges occur over time, which in turn attack the plastic in the insulation.

The plastic is destroyed locally and there are electrical erosion phenomena. This destruction of the insulating system is delayed by the platelet-shaped, partially discharge-resistant mica in the insulation system by an erosion path extension, so that a minimum service life of 20 years can be guaranteed. Nevertheless, an erosion path continuously forms throughout the life cycle through the insulation system until finally the ground fault occurs in the electrically rotating machine. If now the electric field strength of 3.5 kv / mm - for example, 4,5 raised kV / mm, the electric Erosionsweg frühzeiti ^¬ ger would be formed and for example, already 5 years As far back ground fault and thus lead to total failure.

The thickness of the insulation system is basically as small as possible to choose, in order to achieve high Wirkungsgra ^¬ de of the machines. In order to increase the power density in the generator and electric motor, it is endeavored to reduce the thickness of the insulation system, for example by about 20%. This inevitably leads to increasing electric field strengths in the insulation system from - again, for example, 3.5 kV / mm to 4.5 kV / mm and thus to an increased electrical see partial discharge activity. The commonly used insulation systems allow permanent operating field strengths of 3.5kV / mm with a technically possible lifetime of at least 20 years. Previously used carbon-based as base resins for electrical insulation and in particular as impregnating resins for winding tape insulation preferred epoxy resins which are in liquid form on a carbon-based (-CR ₂ -) _n ^_ return ^¬ grat all possible functional groups, for example also carry epoxy groups. These are reacted with hardener to a thermosetting plastic, which forms a casting and / or, for example, the impregnation of Wickelbandiso ^¬ lation. The object of the invention is to provide an approach for improving insulation systems for medium and high-voltage machines by providing a new and better, in particular partial discharge-resistant insulating material. This is particularly of great inte- ress, since the reduction of the insulation system by 20% about 600 Kg - for example, in a 370 MVA generator - to Isola ^¬ tion material, such as plastic, mica and / or glass cloth can be saved. This object is achieved by the subject matter of the present ^¬ be signed and the claimed invention as is disclosed in the description of the figures and the claims. The present invention is therefore a Isola ^¬ tion material and / or impregnating resin for a Wickelbandiso ^{¬-regulation,} at least a base resin, a curing agent and optionally additives comprising, characterized, in that at ^¬ least a portion of one of the insulation system to

Duromer curing base resin is a siloxane-containing compound ^¬ tion, which forms a -SiR ₂ -0-backbone in the duromer, is. In addition, the subject matter of the present invention is an insulation system, for example an insulation system for a rotating electrical machine, in particular a medium or high-voltage machine, which can be produced using the insulation material according to the invention.

Here, "R" stands for all types of organic radicals which are suitable for curing and / or crosslinking to an insulating material which is suitable for an isolation system. <br/> In particular, R represents -aryl, -alkyl, -heterocycles, nitrogen, oxygen and / or sulfur-substituted aryls and / or alkyls.

In particular, R may be the same or different and represent the following groups:

Alkyl, for example methyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, isopentyl, cyclopentyl and all other analogs up to dodecyl, ie the homolog with 12 carbon atoms;

Aryl, for example: benzyl, benzoyl, biphenyl,

Toluyl, xylenes, etc., in particular, for example, all

Aryl radicals whose structure corresponds to Hückel's definition of aromaticity

Heterocycles: in particular sulfur-containing heterocycles such as thiophene, tetrahydrothiophene, 1,4-thioxane and homologues and / or derivatives thereof,

Oxygen-containing heterocycles, e.g. Dioxane

Nitrogen-containing heterocycles, e.g. -CN, -CNO, -CNS, - N3 (azide) etc.

Sulfur-substituted aryls and / or alkyls: e.g. Thiophene, but also thiols.

The Hückel rule for aromatic compounds refers to the context that planar, cyclic durchkonjugierte molecules comprising a number of Π-electrons, which can be represented in the form of 4n + 2 comprises, have a special sta ^¬ ity, which also is called aromaticity. According to an advantageous embodiment of the invention, in addition to the monomer-functionalized and / or oligomeric component functionalized for polymerization, which has a -SiR ₂ -O-backbone, the resin also comprises at least one monomeric or oligomeric resin component functionalized for the polymerization a hydrocarbon so (CR ₂ -) units comprising backbone. For this purpose, are, for example Epoxidfunktionali ^¬ catalyzed components, such as bisphenol F diglycidyl ether (BFDGE) or bisphenol A diglycidyl ether (BADGE), polyurethane and mixtures thereof. Preference is given to epoxy resins based on bisphenol F diglycidyl ether (BFDGE), bisphenol A diglycidyl ether (BADGE) or mixtures thereof.

For example, the monomer or oligomeric component functionalized for polymerization, which has a -SiR ₂ -O-backbone, is combined with one or more compounds selected from the group of the following compounds for the base resin:

undistilled and / or distilled, optionally reactive dilute bisphenol A diglycidyl ether, undistilled and / or distilled, optionally reactive dilute bisphenol F diglycidyl ether, hydrogenated bisphenol A diglycidyl ether and / or hydrogenated bisphenol F diglycidyl ether, more pure and / or with solvents diluted epoxy novolac and / or epoxy-phenol novolac, cycloaliphatic epoxy resins such as 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylate eg

CY179, ERL-4221; Celloxide 2021P, bis (3,4-epoxycyclohexylmethyl) adipate, eg ERL-4299; Celloxide 2081, vinylcyclohexene diepoxide, eg ERL-4206; Celloxide 2000, 2- (3,4-epoxycyclohexyl-5,5-spiro-3,4-epoxy) -cyclohexane-meta-dioxane, eg ERL-4234; Hexahydrophthalic acid diglycidyl ester, eg CY184, EPalloy 5200; Tetrahydrophthalic acid diglycidyl ether, eg CY192; glycidated amino resins (N, N-diglycidyl-para-glycidyloxyaniline eg MY0500, MY0510, N, N-diglycidyl-meta-glycidyloxyaniline eg MY0600, MY0610, Ν, Ν, Ν ', Ν'-tetraglycidyl-4,4'-methylenedianiline, for example MY720, MY721, MY725, as well as any mixtures of the aforementioned compounds. Glycidyl-based and / or epoxy-terminated aryl and / or alkyl siloxanes, such as, for example, glycidoxy-functionalized, in particular glycidoxy-terminated siloxanes, are suitable as polymerization-functionalized monomeric or oligomeric component having a -SiR ₂ -O-backbone. Thus, for example, a siloxane such as 1,3-bis (3-glycidyl-oxypropyl) tetramethyldisiloxane, the DGTMS or glycidoxy-terminated phenyl-dimethylsiloxane in monomer and / or in oligomeric form, and in any mixtures and / or in the form of derivatives , It has been shown that at least doubly functionalized siloxane monomers, which can be used for the production of thermosets, are suitable here. As the hardener suitable cationic and anionic Härtungska ^gas catalytic converters, such as organic salts such as organic ^¬ specific ammonium, sulphonium, iodonium, phosphonium and / or imidazolium salts, and amines, such as tertiary amines, pyrazoles and / or imidazole Links . As an example, 4, 5-dihydroxymethyl-2-phenylimidazole and / or 2-phenyl-4-methyl-5-hydroxymethylimidazole may be mentioned here. But it can also

oxirane group-containing compounds, such as

Glycidyl ether can be used as a hardener. Conventionally, acid anhydrides are also used successfully as hardeners in the insulation materials. However, their toxicology is no longer quite uncontroversial.

According to an advantageous embodiment of the invention, the carbon-based curing agent is also to be replaced in whole or in part by siloxane-based hardeners having the same functionalities.

According to an advantageous embodiment of the invention, the insulating material and / or impregnating resin for a winding tape insulation also includes additives, such as sintering aids, reactive accelerators and / or fillers, which can be used both as nanoparticles. may lie angle and as a filler in the micrometer range before ^¬.

It has been found that in the insulating fabric comprising the cured base resin, a ratio of -S1R ₂ -O return ^¬ grat to (-CR ₂ -) backbone, such as 1: 8 to 1: 4 is most favorable, i.e. that in the insulation material concerned, the hydrocarbon-based compounds are present quantitatively 4 to 8 times as the siloxane-based compounds. The proportions are based on the stoichiometry, ie are mole percentages.

The siloxane-containing component is thus present in an amount of 10 to 50 mol% in the base resin of the insulating material. In particular, it is preferred if the amount of siloxane-containing component in the base resin is not more than 20 mol%, in particular not more than 18 mol% and particularly preferably not more than 15 mol%. The partial discharge resistance of the insulating material is virtually increased by the presence of a certain amount of S1R ₂ -O- forming monomers or oligomers in the base resin. Figure 1 shows the comparison of discharge volumes to elekt ^¬-driven aging at 10 kV. On the x-axis, the proportion of S1R ₂ -O- forming compound in the base resin is applied, the zero line is at 100% (-CR ₂ -) backbone or backbone-forming base resin.

It can be seen that between 0 and 10 mol% of "exchanged -CR ₂ compound" the erosion volume, plotted on the y-axis, drops abruptly from about 37 to 6. This means that the erosion volume practically goes by a factor of 9 At 20 mol% of S1R ₂ -O- forming compound with 80 mol% CR ₂ - compound in the base resin results in a minimum, which persists to about 30mol% of S1R ₂ -O- forming compound. In the present case, to replace the conventional resin component by a -SiR ₂ ~ 0-containing monomer, the 1,3-bis (3-glycidyloxypropyl) tetramethyldisiloxane was used. For measurement, the hardened insulation material was deliberately exposed to electrical discharges. After a certain time, the eroded volumes were scanned by a laser and thus the eroded volume - or Ero ^¬ sion depth - evaluated. The paging parameters were as follows:

Temperature: room temperature; Atmosphere Air 50% RH; Duration 100h; Voltage 10kV.

It has been shown that even with a low substitution of the conventional epoxy resin, such as the bisphenol A diglycidyl ether (BADGE) by a S1R ₂ -O- containing monomer after curing, a significant increase in the partial discharge resistance can be achieved results in a significantly reduced eroded volume.

The same phenomenon could be found in the substitution of the

Bisphenol A diglycidyl ether (BADGE) can be observed through a SiR ₂ -0-containing product "Silres®" and / or Silikoftal with an at least two functionalized, glycidoxy-terminated phenyl-dimethylsiloxane monomer, as shown in FIG.

In both figures, an optimum of the reduced erosion volume is seen in a substitution of the -CR ₂ - backbone-forming compound from 20 mol% to 30 mol% by the -SiR ₂ -O- containing backbone-forming compound.

The substitution of -CR ₂ - backbone forming compound be ^¬ acts but in the cured insulation material a deterioration of mechanical properties, so that as little as possible and as much as necessary SUC ^¬ gen of substitution should. According to a preferred embodiment of the invention, therefore, be up to 10 mole%, preferably up to 15 mol% and insbeson ^¬ particular preferably up to 20 mol% of the compound (s) in the base resin ^¬, the ~ form a -CR ₂ backbone by corresponding functionalized compounds having a -SiR ₂ 0 backbone ausbil ^¬ substituted ~.

In this area, the mechanical properties of the cured insulating material are quite as good as those of the insulating material without compounds that form a -S1R ₂ -O- backbone. In particular, the resulting glass transition temperatures and the memory modules of the substi tuted ^¬ insulating substance are almost identical with those of the forth ^¬ conventional insulation material without substitutions.

In Figure 3, the memory modules and derived glass transition temperatures as a function of degree of substitution are epoxy resin component ₂ -0 backbone, represented by a, a -SiR from ^¬-forming compound such as the "Silres®".

It can be seen that the highest glass transition temperature is to be measured at the 25% substitution.

By the present invention, an insulation material and / or an impregnating resin for a Wickelbandiso ^{¬-regulation} is first introduced, by the presence of compounds in the cured resin constituting ₂ -0 backbone a -SiR shows an interpreting ^¬ Lich increased partial discharge resistance. As a result, the thickness of the insulation system can be drastically reduced, for example by up to 20%.

This results in various advantageous options for product development. On the one hand, it is possible to throttle the circumference, the weight and the costs of the insulated conductors while the conductors are of constant thickness. Second, the space saved can be filled by increased conductor thickness and thus the power per mass of the electric machine can be increased. At the moment, conventional insulation systems for high tension ^¬ voltage machines are designed to keep permanent Be ^¬ operating field strengths of 3.5 kV / mm off for at least 20 years. With the isolation materials presented here, these field strengths could be significantly increased to up to 4.5kV / mm for similar long lifetimes.

Claims

claims

1. insulating material and / or impregnating resin for a winding tape insulation, comprising at least one base resin, a hardener and optionally additives, characterized in ^¬ net, that at least a portion of the insulating system for curing a thermoset base resin a siloxane-containing Ver ^¬ binding which forms a -SiR ₂ -O-backbone in the duromer is.

2. Insulation material and / or impregnating resin according to claim 1, wherein the compounds of the base resin are present in monomeric form.

3. Insulating material and / or impregnating resin according to claim 1, wherein the compounds are present in the base resin oligomer.

4. insulating material and / or impregnating resin according to any one of the preceding claims, wherein the base resin at least 10 mol%, in particular at least 15 mol% comprises a compound which forms a -SiR ₂ -O-backbone.

5. insulation material and / or impregnating resin according to any one of the preceding claims, wherein the curing agent comprises a siloxane-containing component which forms a -SiR ₂ -O-backbone, which carries the corre ^¬ sponding, suitable for curing the base resin functionalities comprises ,

Insulating material and / or impregnating resin according to any of the preceding claims, wherein in the base resin, compounds forming a -SiR ₂ -O-backbone with compounds forming a -CR ₂ - backbone in a stoichiometric ratio of 1: 4 to 1 : 8 are available.

7. insulating material and / or impregnating resin according to any one of the preceding claims, wherein in the base resin, compounds which form a -CR ₂ ~ backbone, percent present in greater mol% vorlie ^¬ conditions as compounds forming a -SiR ₂ -O-backbone.

8. insulating material and / or impregnating resin according to any one of the preceding claims, wherein in the base resin, a glycidyl- and / or glycidoxy-functionalized compound which forms a - SiR ₂ -O-backbone is present.

9. insulation material and / or impregnating resin according to any one of the preceding claims, wherein in the base resin a

Glycidyl ether compound and / or a novolak derivative.

10. insulation material and / or impregnating resin according to any one of the preceding claims, wherein in the base resin

cycloaliphatic epoxy resin is present.

11. Insulation material and / or impregnating resin according to one of the preceding claims, wherein in the base resin is an epoxy-terminated aryl and / or alkyl siloxane as a compound which forms a -SiR ₂ -O-backbone present.

12. An insulating material and / or impregnating resin according to any one of the preceding claims, wherein in the base resin is 1,3-bis (3-glycidyloxyalkyltetramethyldisiloxan), as a compound which forms a -SiR ₂ -O-backbone is present.

13. An insulating material and / or impregnating resin according to any one of the preceding claims, wherein in the base resin, 1,3-bis (3-glycidyloxypropyl) tetra-methyl-di-siloxane as a compound which forms a -SiR ₂ -O-backbone is present.

14. insulation system, in particular for a medium and / or high-voltage machine, comprising an insulating material ^¬ it by hardening an insulating material according to any one of claims 1 to 13.