Active cancellation of transformer noise: Field measurements
1988; Elsevier BV; Volume: 23; Issue: 4 Linguagem: Inglês
10.1016/0003-682x(88)90044-8
ISSN1872-910X
AutoresTruls Berge, O.K.Ø. Pettersen, S. Sørsdal,
Tópico(s)Physics and Engineering Research Articles
ResumoThe paper presents some results from measurements of active noise cancellation on two outdoor transformers. An adaptive signal processor was used to generate 100 and 200 Hz tones in anti-phase with the transformer noise at a single point some distance away from the transformer. The main object was to study the random fluctuations due to changes in the environmental conditions, in the transmission of the transformer noise and the anti-noise. The noise cancellation obtained with the most suitable signal processing was found to be in the range 5–10 dB for the peak (L1) and the equivalent (Leq) levels. The lowest levels (L99) were reduced by as much as 20 dB under certain conditions. The transformer noise is highly directive, and this single-channel system only produced noise cancellation in a narrow zone, which could typically cover one residential house.
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