An active noise reduction system for UHV power transformers

Abstract

Disclosed is an active noise reduction system of an extra-high-voltage power transformer. A vibration sensor of a vibration signal collection module is glued on a transformer to collect a vibration signal of a transformer shell to be used as a reference signal; the signal output by the vibration sensor passes through a pre-amplifier with adjustable gain to be input to an audio chip; a sound pressure sensor is placed in a target noise reduction region; a signal output by the sound pressure sensor passes through the pre-amplifier with adjustable gain and a filter to be input to the audio chip; the audio chip collects a noise signal and performs A / D conversion and transmits the data to a DSP processor; and the DSP processor receives the data from the audio chip, performs adaptive filtering algorithm processing and transmits the processed data to the audio chip; and the data is subjected to D / A conversion and then is input to a power amplifier to drive a speaker to generate noise reductionsound to be counteracted with the transformer noise, so as to realize active noise reduction.

Description

technical field [0001] The invention relates to a transformer noise processing system, in particular to an active noise reduction system for an extra-high voltage power transformer. Background technique [0002] With the expansion of the grid scale, more and more large-scale power transformers are installed near residences and public places, and the noise generated by them seriously affects the work and life of the staff in the station and the surrounding residents. The noise of the transformer body mainly comes from the vibration of the iron core caused by the magnetostriction of the silicon steel sheet when the iron core is excited, and the base frequency is twice the power frequency. Due to the non-linearity of the core material and the difference in the length of the magnetic circuit along the inner and outer frames of the iron core, the noise spectrum also includes integer multiples of the fundamental frequency. Therefore, for a power supply with a frequency of 50Hz, t...

AI Technical Summary

Problems solved by technology

[0005] (1) The current active noise reduction system using the feedforward control method obtains the reference signal through the sound pressure sensor, resulting in the reference signal inevitably including transformer cooling fan noise, environmental noise and secondary sound source feedback noise

The high-frequency components in cooling fan noise and environmental noise can be filtered out through a low-pass filter, but it is difficult to filter out cooling fan noise, low-frequency components in environmental noise and feedback noise from secondary sound sources;

[0006] (2) The reference signal collected by the sound pressure sensor of the current active noise reduction system needs to be filtered first, and then input to the control circuit, and the delay effect of the filter is not conducive to real-time noise reduction;

When the noise intensity is small, the amplitude of the noise signal output by the fixed-gain amplifier is low; when the noise intensity is high, the amplitude of the noise signal output by the fixed-gain amplifier is high, which may exceed the range of the A / D sampling circuit. Low stability of the source noise reduction system

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