Multi-channel active noise control system for power transformer

Abstract

The invention discloses a multi-channel active noise control system for a power transformer which can separately or simultaneously reduce the components approximate to 100Hz, 200Hz and 300Hz in noises of the power transformer and has high degree of automation and a good noise reduction effect. Compared with the noise reduction method of the traditional transformer, the system has a good noise reduction effect on the noise peak approximate to 100Hz, 200Hz and 300Hz; under an ideal condition, the magnitude order of the environmental noise can be reduced to at the microphone; the system manages the input and output of signals in a distributed manner by using a quad-channel signal condition / driving module, has good passageway expansibility and is convenient to realize and maintain; a man-machine interactive module facilitates to manage operation and exchange data; and in addition, the multi-channel active noise control system is less affected by the installation space of the field and is beneficial to the ventilation and heat dispersion of the power transformer.

Description

1. Technical field [0001] The invention relates to a noise control system, in particular to a multi-channel active control system for power transformer noise. 2. Background technology [0002] The power transformer is a device that uses the principle of electromagnetic induction to change the AC voltage. It is mainly used for raising and lowering the voltage of the power transmission and distribution system. Power transformer noise mainly comes from the iron core. The iron core expands and contracts under the action of alternating magnetic flux. Magnetostriction makes the iron core vibrate periodically with the change of excitation frequency. The spectrum characteristics of the generated noise are mainly low-frequency line spectrum, and the frequency is The even multiplier relationship of the power frequency 50Hz is mainly concentrated around 100Hz, 200Hz, and 300Hz. [0003] Noise reduction measures for power transformers can be mainly divided into noise source control and...

AI Technical Summary

Problems solved by technology

In order to effectively shield the noise emitted by the transformer, it is often required that the sound insulation and sound absorption layer be fully enclosed, which will cause the problem of ventilation and heat dissipation of the transformer

The existing solution is to set an air inlet with a certain area and install a muffler at the air inlet, but this will cause poor low-frequency noise control effect

In this case, it can only be solved by thickening the sound insulation and sound absorption layer and lengthening the muffler. However, under certain site conditions, the surrounding space requires a high volume of equipment, so that it is impossible to increase the volume of the equipment and improve the sound insulation effect.

Therefore, the disadvantages of this type of noise control technology for power transformers using sound insulation and sound absorption layers are: 1. The low-frequency noise control effect of transformers is not good; 2. The ventilation and heat dissipation effects are not good in actual use and are limited by the surrounding installation space

In the aspect of transformer noise active control source, an inertial shaker was proposed (X.Liet al..Tuneable inertia shakers for active control, International Journal of Acoustics and Vibration, 6(4), 180-184, 2001); In terms of active control algorithms, a waveform synthesis algorithm was proposed (X.Qiu et al., Analgorithm for active control of transformer noise with on-line cancellation path modeling based on the perturbation method, Journal of Sound and vibration, 240(4), 647-665 , 2001; X.Qiu et al., Awaveform synthesis algorithm for active control of transformer noise: implementation, AppliedAcoustics, 63, 467-479, 2003); although scholars have proposed a distributed transformer based on a single-channel feedback control control unit Noise active control system (P. Micheau et al, Implementation of decentralized active control of powertransformer noise, First European Forum on Materials and Methods for Machinery and Transportation Noise Control, 2001), but there are the following disadvantages: 1. Using feedback control will produce The water bed effect, while reducing the noise of certain frequency components, will increase the noise at other frequencies; 2. Corresponding to a clear noise source such as a transformer, the noise reduction effect of feedback control is lower than that of feedforward using a reference signal Control system; 3. The self-adaptive algorithm used in this system is the standard X-LMS algorithm, which has a large amount of calculation. At the current level of technological development, it can only realize a distributed system based on a single channel, and it is difficult to realize a multi-channel system. Noise control less effective than active control systems with multiple channels

[0005] At present, there is no introduction to the open multi-channel active control system of power transformers. The present invention discloses such a system, and its innovations are: 1. The signal conditioner of the error microphone and the secondary sound source drive module. One-to-one correspondence, a group of four share the chassis to form a signal condition / drive module, and multiple sets of signal conditions / drive modules form the front end of a multi-channel active control system; 2. The adaptive signal processing module uses a digital signal processing chip to form a chassis separately. Both the error signal input interface and the control signal output interface are connected to the signal condition / drive module through the signal line, and the reference signal input interface can be connected to the signal condition / drive module or directly connected to the reference signal sensor; 3. The human-computer interaction module uses computer touch The screen displays the control panel and receives the administrator's operation, and exchanges data with the adaptive signal processing module through the serial port

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