DE1018121B - Outdoor high-voltage composite insulator made of plastic - Google Patents

Description

GERMAN

High-voltage isolators are usually made of ceramic materials of high dielectric strength, high tracking resistance and good Made to be weatherproof. Their disadvantages are their relatively high weight, high substance sensitivity, lack of reliability in a sufficiently tight fit of cemented or puttied and force-transmitting Metal parts as well as the tedious production, caused by laborious, sometimes weeks-long Drying processes and the subsequent firing process. The long production times make it costly Storage required. Furthermore, with ceramic insulators no high dimensional accuracy possible.

Many attempts have already been made to overcome these disadvantages by using or also using: plastics to restrict. So you have, for example, the tensile core made of press paper, hard paper or the like Made in fabric and with a ceramic Surrounding the jacket, or you have a tracking current-resistant insulator made of organic, not creep-resistant per se Insulating material created by the surface creepage distance from insulating material zones composed of different moisture absorption. To do this, you have wrappers made of paper layers used with a ethanol or cresol bond. In another case one has an inner layer made of hard paper or hard linen Core with a cemented on it. Protective cover made of ceramic material or ge ^ - Pressed insulating material is provided, or you have a core made of shredded pressed material in a jacket stored in a laminate pipe. The jacket should be made of polyester resin and glass and the core; made of polyester resin and schnitzel, in both cases of a material that is insufficient Has leakage current resistance.

All these arrangements, which among other things also use hardening substances to fill the cavities of the transformers through polymerization without splitting off volatile constituents, but without giving more precise information in these cases, have not been able to establish themselves on a broad basis, especially not in the case of outdoor insulators for high stresses because the plastics used only individual requirements from the sum of the necessary requirements, be <in them - were able to meet friedigand.

The invention relates to an outdoor high-voltage composite insulator made of plastic which is constructed in such a way that the isolator is used upcoming plastics are assigned special tasks. The invention consists in the combination a made of Melaminharzpreß material existing shell of the composite insulator with one from

Outdoor high-voltage composite insulator
made of plastic

Applicant:

Chemical works Albert,
Wiesbaden-Biebrich, Albertstr. 10-14

Josef Schmitz, Wiesbaden-Biebrich,
has been named as the inventor

Hardenable epoxy resin and made by pouring, injecting or cementing with the jacket firmly connected core. So there is the load-bearing core aas the tensile and bending forces as well as the absorbing dielectric stress. Epoxy resin plastic while for the outer · sheath one Certain tracking current-resistant, sufficiently rollover-proof, scratch- and weather-resistant plastic, namely Melamine resin, is chosen, which mechanically and dielectrically only insignificantly claimed will.

The load-bearing and dielectrically stressed core of the insulator, be it a post insulator, an insulator for a hanging chain or an anchoring chain, is firmly connected to the outer jacket, with the necessary metal parts of the supports, suspension fittings and cable fasteners being embedded in the two core ends. According to the invention takes place for the load-bearing core. Epoxy resin curable in a known manner by the addition of crosslinking agents, which can be firmly connected to the jacket by pouring, injecting or cementing and which can contain suitable extenders or other fillers that affect mechanical, electrical or thermal and, if necessary, also shrinkage. A particular Kriechr current strength of this for the core resin to be used is not required, since the core is covered at its · outer end surfaces with superior ¹ metal parts, so that the core material does not come in flashovers with the flashover sparks in contact. The tensile strength of the epoxy resin used for the core should be at least that of the known high-voltage ceramic type 110 / DIN

709> 757/235

40 685, ie at least about 300 to 500 kg / cm ² .

For the outer jacket of the composite insulator according to the invention, which takes over the rollover safety Criminal current-resistant molding compounds on melamine resin bases are used.

: In the following example, as shown in Fig. 1, an inventive High-voltage composite insulator described, arbitrarily being approximately the outer Form of a high-voltage overhead line cap insulator according to DIN 48007 is selected.

The outer jacket α is a molded part from a tracking current-resistant melamine resin molding compound, the inner, continuous cavity of which widens conically upwards and downwards. A metal cap b is, for example, pressed, screwed or glued onto the upper opening. This cap b carries towards the inside, ie protruding into the opening of the jacket, a downwardly conically widening approach in the form of a clapper c. while at the top it can be designed as a clapper pan in a known manner. The free interior of the jacket is filled with a tensile and puncture resistant, castable, curable and not necessarily tracking current resistant epoxy resin d , in which the lower clapper e is embedded. The lower metal cap! e can have a metal collar g , optionally provided with filler openings /, which at the same time ensures centering. The protruding metal collar d over the cast epoxy resin side has g but also even the point in arcing across the outer insulator each Kriechstromgefährdung the core d reliably excluded, as the flashover between the, b d protruding lower edge of the metal cap also over the core and the outer edge of the metal collar g and thus extends exclusively over the tracking current-resistant Melaniinharzpreßstoffmantel α .

The exemplary embodiment chosen here merely as arbitrary High-voltage composite insulator described for the invention It has a number of advantages, which are explained in more detail below.

In a ceramic insulator of a similar design, the upper metal cap b must be brought down close to the plate-like part of the insulator due to the required cemented surface, while it can be kept very short according to the present invention because the clapper c in the core serves to transmit power. As a result, the flashover distance over the outer jacket α is greater than that of the ceramic insulator with an otherwise identical design. The short cap b which can be used for the composite insulator according to the invention also has the advantage that the electric field is preferably oriented in the axial direction of the insulator, i.e. in the longitudinal direction of the dielectrically high-quality plastic core and not across the insulator, whereby the leakage current-resistant molded material jacket α in the desired sense is dielectrically relieved.

The dielectric relief of the cladding α can also be largely controlled by correspondingly influencing the dielectric constant of the core and cladding material.

The use of tracking resistance, melamine resin molding compounds because of its known relatively high post-shrinkage, this guarantees the coat for a reliable and tight bond between sheath and core.

When using epoxy resins for the The core of the post-shrinkage of the melamine resin pressed fabric jacket is of particular advantage because it is the counteracts and compensates for natural volume shrinkage of the cast resin core.

The use of epoxy resins offers special guarantees that the core is completely free of. Air and gas inclusions can be kept, where the necessary reliability in the dielectric strength is achieved. If necessary, the degassing of the core can be supported by the application of a vacuum. The imperative that the core must be free of air and gas is an essential reason for the composite structure of the insulator according to the invention, because even if there were synthetic resin molded material that could meet all the individual requirements for a high-voltage insulator, no high-quality material could be used -Isolator are made from it because the electrically stressed shaft cannot be pressed without air, water vapor or other gas inclusions due to its thick walls, which are necessary for reasons of strength.

Due to the composite structure, the outer jacket α , which assumes the leakage current safety, remains mechanically relieved, at least in the case of operational tensile stress. Compared to the ceramic insulator of the usual design, which is also constantly under internal mechanical stresses in the plate-like part, this has the advantage of greater security against hailstorms.

As is known, ceramic insulators cannot be manufactured with high dimensional accuracy, so that generally a tolerance of + 5% cannot be fallen below. In contrast, the subject matter of the invention for external tracking current fasting Preßstoffmantel reliably a dimensional accuracy of. Maintain at least ± 1%. The ideal deformability when pressing the outer shell is allowed In addition, a significant refinement in the formation of individual ribs and grooves and thus, if necessary, a better alignment was achieved Conditions regarding field protection and rain protection.

The weight of the composite insulator from the leakage-proof, mechanically relieved melamine resin molded shell and the continuous, the mechanical one and dielectric strength epoxy resin core is at most about dia Half compared to a ceramic insulator of the same dimensions and the same performance ·. The coat can due to its mechanical relief, especially in its plate-like part, thinner-walled than in the ceramic version be held, whereby a further significant weight saving is achieved. Next to The 50 to 70% lower weight ensures transport advantages and a lower risk of breakage rough transport, during assembly and also when occasionally falling on hard ground. Further The considerably lower weight of extra-high voltage overhead lines provides significant relief the masts and their booms.

In Fig. 2, an anchoring chain is shown as a further exemplary embodiment. The individual shell members α are designed in such a way that they are centered: can be placed on top of one another in the desired number. After the upper metal cap b has been glued on, the jacket members α are also glued to one another and then the continuous core is injected or poured in , for example through the openings / the lower cap g. An epoxy resin can also be used for gluing.

The example selected in Fig. 3 shows a hanging chain with a common core, which in the same Way as the example according to Fig. 2 is made. The special design of the outer molded material jacket α allows the production of any number of links, rigid chains as well as the production individual caps with clapper and clapper pancake, as shown in Fig. 1. The letters in the Figs. 2 and 3 correspond to those of the example according to Fig. 1.

Claims (1)

PATENT CLAIM: 10 Outdoor high-voltage composite insulator with an outer, creepage-resistant jacket and an inner, puncture-proof and mechanical solid core made of plastics, characterized by the combination of a melamine resin molded material existing jacket with a hardenable epoxy resin made by casting, Injection or cementing with the core firmly connected to the jacket. Considered publications: German Patent Nos. 347 024, 437 152; Swiss patents No. 149 210, 138118; French Patent No. 1,040,850; British Patent No. 537,834; U.S. Patent Nos. 2,661,390, 2,213,922; "Kunststoffe", 1953, No. 10, pp. 387 to 392; 1951, No. 11, pp. 365 to 373; E. T. Z-B 1952, pp. 179 to 184; "Electrical engineering and mechanical engineering", 1953, issue 11, pp. 237 to 247; 1951, issue 15, pp. 353 to 360. 1 sheet of drawings © 709 757/235 10.