DE102008061552A1 - Method for reducing noise of electrical transformer, involves determining current operating point of transformer and providing measurement protocol for characterizing operating point dependent behavior of transformer - Google Patents

Abstract

The method involves determining current operating point of a transformer (10) and providing a measurement protocol (15) which characterizes an operating point dependent behavior of the transformer with reference to releasing noise. Compensation noises are generated for a current operation point of the transformer. The compensation noises are determined according to the principle of the noise cancellation from the sounds specified in the measuring protocol for the current operating point. An independent claim is also included for a device for reducing noise of an electrical transformer.

Description

The The invention relates to methods and devices for noise reduction for an electrical transformer.

at electrical transformers, in particular for power transformers, During operation, noises occur, which are perceptible as a hum. When idling the transformer, the noise in the essentially due to mechanical vibrations of the transformer core generated, in turn, by changes in length the core sheets are caused. Under load arise in the transformer electromagnetic forces that cause vibrations in the windings lead the Transformtors. The vibrations are almost undamped by the transformer oil and over transferred the boiler walls and the resulting Noises are then released as airborne sound.

It is known to reduce the noise that for example, the transformer core vibration damped is housed inside the transformer tank. Farther the whole transformer can be on a vibration damped Floor can be set up and / or it can sound-absorbing Partitions are placed around the transformer around.

Another possibility for noise reduction of transformers is from the DE 42 28 101 A1 known. There soundproofing concentrators are provided for noise reduction. In the introduction to this document is explained that the application of so-called anti-sound in transformers would not have led to success.

task The invention is to provide methods and apparatus for a to create electrical transformer with little effort lead to a far-reaching noise reduction.

The Invention solves this problem by the methods and devices according to claims 1 to 4.

The Invention consists of two parts. In a first part becomes one Measurement log determines that the operating point-dependent Behavior of the transformer with regard to the emission of noise characterized. This measurement protocol is then usable Compensation noise for the current operating point of the transformer. In a second part, the Compensation noise for the current operating point of the transformer, the compensation noises according to the principles of so-called anti-noise from those in the measurement protocol for the current operating point specified noise be determined.

The Invention has the advantages that in the second part no effort for the actual measurement of that Transformer generated noise is required. Instead of this will be there in a simple manner determined in the first part Measurement protocol used. Furthermore, this measurement protocol may optionally be used for every transformer of the same type, so that in this respect a reduction of the effort achievable is.

simultaneously is achieved with the inventive generation of compensation noise a substantial extinction of the transformer reached noises. This will be easier Way through the application of the principle of so-called anti-sound accomplished. By this principle can essentially only by arithmetic measures a substantial noise reduction will be realized.

at An advantageous development of the invention are in the radiation area the compensation noise residual noise measured and the compensation sounds are so detuned, that the residual noise is minimized. By this in turn Essentially only arithmetic measures can be a scheme built and thus minimized noise reduction or even brought to zero.

Further Features, applications and advantages of the invention result from the following description of exemplary embodiments of the invention, which are illustrated in the figures of the drawing. All described or illustrated features form for itself or in any combination the subject of the invention, independently from its summary in the claims or their relationship and regardless of theirs Formulation or representation in the description or in the drawing.

1 shows a schematic block diagram of an embodiment of a first part of a device according to the invention for noise reduction for an electrical transformer, 2 shows a schematic block diagram of an embodiment of a second part of the device according to the invention, and 3 shows the device of 2 with a supplement.

The invention described below consists of two parts. A first, in the 1 shown part is preferably carried out at the end of the production of a transformer and thus usually at the manufacturer of the transformer. A second, in the 2 and 3 shown part is after Installation of a transformer at its place of operation and thus carried out in normal operation of the transformer. This second part thus usually concerns the operator of the transformer.

In the 1 is a transformer 10 represented, which is placed on a floor, and generates noises in its operation. These sounds are sound waves that are substantially uniform in space around the transformer 10 spread. The pitch of the sounds is determined by the frequencies and the volume by the associated amplitudes of the sound waves.

At a distance to the transformer 10 is a microphone 12 present, that with a sound measuring device 13 connected is. With the help of the microphone 12 and the sound measuring device 13 The current frequencies and volumes available from the transformer 10 emitted noises are measured. The sensitivity of the microphone 12 For example, it can have a frequency range from about 20 hertz to about 20,000 hertz. In terms of volume, the sensitivity of the microphone 12 among other things, the distance of the same from the transformer 10 be adjusted.

It will now be the transformer 10 in the already mentioned first part of the invention set to a plurality of predetermined operating points and the associated frequencies and amplitudes are measured at each operating point. In the presently described exemplary embodiment, therefore, there is a single measurement result from an operating point, the measured frequencies at this operating point and the measured amplitudes associated with the frequencies. Each of these results is saved. The measurement results for all operating points thus form a measurement protocol 15 of the transformer 10 stored in saved form.

For carrying out this first part of the invention, the sound measuring device 13 have a digital computing device and the storage can be done for example on an electronic memory that can be separated from the computing device and thus moved to another location.

The predetermined operating points may be, for example, the idling of the transformer 10 , a plurality of consecutive load points as well as the full load of the transformer 10 act. The operating points may be characterized for example by the respective load current that the transformer 10 applied. This load current can be measured, for example, by a current transformer or otherwise. It is understood that the operating points by others and / or by each several operating variables of the transformer 10 can be fixed.

Preferably, a measurement path can be selected, as in the DIN EN 60076-10, "Power transformers - Part 10: Determination of noise levels" is described. The respective frequencies and amplitudes can then be measured and stored along this measuring path.

It is understood that other possibilities are conceivable, such as the individual measurements on the operating range of the transformer 10 can be distributed. It is also understood that not necessarily the frequencies and / or amplitudes must be measured, but that other parameters of the transformer 10 generated noise can be measured and stored alternatively or in addition.

As already mentioned, the illustrated first part of the invention is preferably made by the manufacturer at the end of the manufacture of the transformer 10 executed. It is understood that this first part but also subsequently and thus, for example, by the operator at the location of the transformer 10 can be carried out.

At the end of the first part is the measurement protocol 15 present the behavior of the transformer 10 in terms of its delivery of noise during its operation.

As already mentioned, the second part of the invention relates to the normal operation of the transformer 10 , This is in the 2 shown. In the 2 is the same, based on the 1 described transformer 10 now shown at his location. The transformer 10 is parked on a floor and produces noises in its operation.

It is a sound generating device 17 provided with a speaker 18 connected is. The sound generating device 17 is like that with the transformer 10 connected to that of the current operating point of the transformer 10 to the sound generating device 17 is transmitted. In the presently described embodiment, the sound generating device receives 17 for this purpose, a load current of the transformer 10 corresponding signal.

Furthermore, the sound generating device 17 the measurement protocol 15 known, which has been determined by the first part of the invention. For this purpose, the measurement protocol 15 of the Sound generator 17 taken over in some way. This can for example be realized by the fact that the sound generating device 17 is provided with a digital computing device that can be connected to an electronic memory on which the measurement protocol 15 is stored.

In the presently explained second part of the invention are of the sound generating device 17 now produces compensation noise from the speaker 18 be issued acoustically. The compensation noises are determined according to the principles of so-called anti-noise. Anti-sound is artificially generated with the aim of eliminating disturbing noises by means of so-called destructive interference. Thus, the compensation noises are generated just so that they have an opposite polarity to the noise to be canceled.

In the present exemplary embodiment, the sound generation device determines 17 the compensation noise depending on the measurement protocol 15 and the currently existing operating point of the transformer 10 , The sound generating device 17 So receives the current operating point. of the transformer 10 and reads the frequencies and amplitudes associated with that operating point from the measurement protocol 15 out. Thereafter, compensation frequencies are calculated which have an opposite polarity to the read-out frequencies. For example, the compensation frequencies can be generated by shifting the phases of the frequencies read out by π / 2. These compensation frequencies eventually become the same amplitudes as the read amplitudes through the loudspeaker 18 output.

As has been explained, those are from the speaker 18 currently issued compensation noise capable of the current operating point of the transformer 10 in the measurement protocol 15 delete stored sounds. In the present second part of the invention it is assumed that the in the measurement protocol 15 stored sounds largely coincide with those sounds that the transformer 10 at its place of operation 2 actually generated. This assumption is based on the fact that the noise behavior of the transformer 10 at its place of operation does not differ from that noise behavior that the transformer 10 in the first part of the illustrated invention. The actual of the transformer 10 Noise generated at its operating location is therefore not measured in the second part of the invention.

In the radiation area of the loudspeaker 18 Thus, the actual of the transformer 10 generated noise is largely extinguished by the output from the speaker compensation noise. This means that there is a considerable reduction in noise in this radiation area.

It is understood that the compensation noise in the second part of the invention also over several speakers 18 can be output in different radiation ranges. It is possible that for each radiation area a separate measurement protocol 15 is present, in the first part of the invention especially for this radiation range of the transformer 10 has been determined. It is also possible that for each radiation area a separate sound generating device 17 is available.

As has been explained, the first part of the invention preferably becomes the manufacturer of the transformer 10 carried out. The effort required for this is required only once. As also explained, the measurement protocol generated in the first part becomes 15 then at the same transformer 10 for the implementation of the second step.

Preferably, the measurement protocol 15 not just for the same transformer 10 but for any transformer of the same type as the transformer 10 is.

In the 3 is a modification of the embodiment of 2 shown. The 3 therefore largely corresponds to the 2 , which is why the same components are marked with the same reference numerals. With regard to these matching components is based on the above explanations of 1 and 2 directed.

The only difference of 3 in comparison to 2 is that a microphone 19 is present, that with the sound generating device 17 connected is. The microphone 19 is arranged approximately in the core of that radiation area, in which the speaker 18 gives off the compensation noise.

With the help of the microphone 19 the residual noise is measured after the extinction of the transformer 10 generated noises are still present by the compensation noise. Such residual noise may possibly still be present that the above-explained assumption does not fully correspond to the facts and thus a complete extinction in the basis of the 2 explained second part of the invention is not achieved.

Be through the microphone 19 detected any residual noise, so the compensation noise from the sound generating device 17 so detuned that the residual noise as small as possible. This detuning can be carried out as a function of the residual noise, in particular frequency-dependent. It can be built in this way a scheme in which minimizes the residual noise as the size to be controlled or zero possible.

With the microphone 19 Thus, they are not those of the transformer 10 noise generated, but only in the radiation of the speaker 18 still existing residual noise. At these residual noise already has an extinction of the transformer 10 Noise generated by the compensation noises occurred.

If necessary, the microphone 19 only for a finite period of time, for example one month or six months. The compensations of the compensation noises calculated during this period can then be stored as a function of the operating point. After the period of time, these moods can then be readily taken into account, although the microphone 19 no longer exists. In this way, the minimization of noise reduction can ultimately be achieved without a permanent effort.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 4228101 A1 [0004]

Cited non-patent literature

• - DIN EN 60076-10, "Power transformers - Part 10: Determination of noise levels" [0019]

Claims (7)

Noise reduction method for an electric transformer ( 10 ), where the current operating point of the transformer ( 10 ), characterized in that a measurement protocol ( 15 ), which determines the operating point-dependent behavior of the transformer ( 10 ) and that compensation noises for the current operating point of the transformer ( 10 ), wherein the compensation noises according to the principles of the so-called anti-noise from the in the measurement protocol ( 15 ) for the current operating point. Noise reduction device for an electric transformer ( 10 ) with means for determining the current operating point of the transformer ( 10 ), characterized in that a sound generating device ( 17 ), which is a measurement protocol ( 15 ) that determines the operating point-dependent behavior of the transformer ( 10 ) are characterized with regard to the emission of noises, and that the sound generating device ( 17 ) is designed such that compensation noises for the current operating point of the transformer ( 10 ), wherein the compensation noises according to the principles of the so-called anti-noise from the in the measurement protocol ( 15 ) for the current operating point. Noise reduction method for an electric transformer ( 10 ), where the current operating point of the transformer ( 10 ), characterized in that a measurement protocol ( 15 ), which determines the operating point-dependent behavior of the transformer ( 10 ), and that the measurement protocol ( 15 ) is suitable for compensating noise for the current operating point of the transformer ( 10 ), wherein the compensation noises according to the principles of the so-called anti-noise from the in the measurement protocol ( 15 ) for the current operating point. Noise reduction device for an electrical transformer ( 10 with means for determining the current operating point of the transformer ( 10 ), characterized in that a sound measuring device ( 13 ), with which a measurement protocol ( 15 ), which determines the operating point-dependent behavior of the transformer ( 10 ), and that the measurement protocol ( 15 ) is suitable for compensating noise for the current operating point of the transformer ( 10 ), wherein the compensation noises according to the principles of the so-called anti-noise from the in the measurement protocol ( 15 ) for the current operating point. Method or device according to one of the claims 1 to 4, wherein the compensation noises generated in such a way be that they have an opposite polarity to the for the current operating point specified noise exhibit. Method or device according to one of claims 1 to 5, wherein the current operating point of the transformer ( 10 ) is characterized by a load current. Method or device according to one of the claims 1 to 6, wherein in the radiation region of the compensation noises Residual noises are measured, and that the compensation noise be so detuned that minimizes the residual noise become.