DE2422860A1 - AIR-COOLED TRANSFORMER - Google Patents

Description

, TRANSFORMERS UNION AKTTENGESEI.LSCHAFT 7 Stuttgart-Bad Cannstatt, Deckprstrasse 5

FST 73/75 Ln 7 Stuttgart, April 26th PT-S / Lehmann / ho

Air-cooled transformer

The invention relates to an air-cooled transformer with one or more axial cooling channels between core and winding, the windings and winding parts, in particular a transformer with cast in synthetic resin Windings.

Because of the increasing energy density, especially in metropolitan areas, energy is provided for the consumer more and more often with high to medium voltage, like that that a tension on consumption voltage immediately at Consumer is necessary. In metropolitan areas, this is also done. you are housed in (lon buildings, in which way the reduced risk of fire and the reduced risk of a

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S098A8 / 05U

FST 73/75 s -Z- "Οίι ·

Soil contamination prefers k \ ins tharz i sol iered dry-type transformers instead of liquid s itol i ts and -cooled devices are used.

Because of the placement of such transformers in buildings there are particularly high requirements for low noise levels of the devices. Well dry-type transformers exhibit in itself because of the lack of liquid in the jacket a higher noise level on al.> comparable liquid-insulated transformers. Therefore must with Dry transformers <! He noise development and the Noise emission can be combated by special measures.

Dry transformers generally consist of the laminated core, which is to be regarded as the excellent source of noise due to its magnetostrictively excited vibrations, as well as coaxially surrounding coils of the legs of the core, which can be accommodated in one or more coaxial cylindrical bodies. These windings, especially if they can be viewed as largely rigid, undamped bodies in synthetic resin encapsulation, represent vibratory structures which, stimulated by the core vibrations, can contribute more or less to the development of noise. The air channels between the core and winding and between the windings or winding parts, similar to the air columns in organ pipes, are vibrating structures that can be excited to vibrate by vibrations at frequencies that are close to their natural resonance frequency.

It is already known to avoid the formation of standing waves in cooling channels by choosing the geometric measurements from or by adding discontinuities (OS 2 207 205).

509848/0 514

FST 73/75 Ln. $. - 3 -

Now only those in transformer windings can be found in such air ducts. Created waves, but this Luftknniilo act ph \> ika] ish lräume as shark, so SÖF fnimgon to dcri'ii ßcgreii / ung (> n the Vätidon and the inputs and Austr i 11, sound re fl ect ion _k s The sound energy density in a room and thus the noise level is proportional to the sound power emitted by a sound source in this room and, conversely, the sound absorption capacity of the room. A measure of the sound absorption capacity is the reverberation time, which is dependent on the volume of the room Room and its average sound absorption capacity.

The smaller the room and the greater its sound absorption capacity, the shorter the reverberation time and thus the shorter the increase in noise in the closed room compared to the noise in the free sound field. Conversely, the larger the The reverberation time of a cooling duct space is, the greater it becomes the increase in pleasure and thus also the noise development and noise emission to the outside.

The reverberation time can only be achieved by dividing the room reduced, its scarf 1 absorption capacity by sound-absorbing Element e to be improved.

The object of the invention is to sustainably reduce the increase in noise as a result of the reverberation in the cooling channels. This is achieved according to the invention in that the Reverberation time of the underground space formed by a cooling channel is reduced by adding sound-absorbing material.

S09848 / G5U

FST 73/75 Ln - Jf -

This sound-absorbing material is in its simplest form Wise and without significant hinderance of the cooling air flow in the form of narrow, axially laid, strip-shaped bodies brought in.

Based on the attached drawing, which shows a cross section through a wound leg of a transformer illustrates embodiment f and the mode of operation the invention explained in more detail.

The stepped core leg 1 is surrounded by a winding 3 with the interposition of a cooling channel 2, which in turn is coaxially encompassed by the outer winding 3 ' after a further cooling channel 2. In the cooling channel between the core leg and the inner winding, the options for attaching the strip-shaped body made of sound-absorbing material are now shown: The body can bridge the full span between the outer surface of the core leg and the inner surface of the winding, as shown by the body h ; the body can only be attached to the inner surface of the core as at 5 or to the inner surface of the winding as at 6; or it is simply hung freely in the duct without touching the jacket surfaces, as in 7.

The strip-shaped bodies made of sound-absorbing material which are introduced according to the invention enable a considerable reduction in the noises emitted by the transformer without making the optimal design of the transformer more difficult. In particular, the invention offers the possibility of also being used subsequently on the finished transformer, for example during or after the measurement in the test field, so that the noises emitted can still be reduced at this stage.

509848/0514

FST 73/75 Ln -S-

As a material for these sound-absorbing, strip-shaped bodies, any sound-absorbing material is suitable, which above all should have a high degree of sound absorption for the frequency spectrum of the transmission noise and which can cope with the other conditions set for the resulting excess temperature UtPIi ₁ have to be. These conditions will above all be met by the diverse Minpralwol! Products developed for thermal insulation purposes.

- claims

509848/0514

Claims (1)

FST 73/75 Ln - Sk - Claim r Air-cooled transformer with one or more axial cooling channels between core and winding, the windings and winding parts, characterized in that that the reverberation time of the reverberation room formed by a cooling channel by introducing sound-absorbing Material is decreased. Transformer according to claim 1, characterized in that that in the cooling channel axial Iister-shaped body are introduced from sound-absorbing material. Transformer according to Claims 1 and 2, characterized in that the strip-shaped bodies form the cooling channel bridge between the inner and outer surface. k. Transformer according to Claim 2, characterized in that the strip-shaped bodies only bear against the inner jacket surface. 5 · Transformer according to claim k _t, characterized in that the inner jacket surface of the cooling channel is formed by the core. 6. Transformer according to claim 2, characterized in that that the strip-shaped body only on the outer egg surface of the cooling duct. 509848/0514 FST 73/75 Ln - t - 7- transformer according to claim 2, characterized in that the strip-shaped bodies are free-standing at a distance
or are arranged freely hanging between the lateral surfaces of the channel. 8- transformer according to claim 1, characterized in that that part of the surfaces of the core and / or the windings absorb sound are occupied. 509848 / 05U ■ s ·. Blank page