Active cancellation of transformer noise: Volume 1, Overview; Volume 2, Computer simulation; Volume 3, Eight-channel digital controller. Final report
The object of this research was to investigate the attenuation of substation transformer hum produced by an active control system. Active cancellation is achieved by the generation of a replica of the original sound which is added to the original in reversed phase. Active noise control offers an alternative to large barriers for attenuating transformer noise. Barriers do not work well at the low frequencies of transformer hum and noise reductions greater than 12 dB are generally not practical. In contrast, active cancellation works best at low frequencies. This project is a follow-on to work done under the sponsorship of the Niagara Mohawk Power Company where the goal was to produce global cancellation. That project proved the feasibility of active cancellation but the analog, controller used proved to be increasingly unstable as the number of control channels was increased. The objective of the project reported here was to investigate the attenuation of the transformer hum over 60{degrees} of azimuth employing a number of secondary sound sources forming an ``active wall`` on one side of the transformer. An active control system was developed, centered around a multichannel programmable adaptive controller, implemented digitally and based on a microcomputer. It is inherently stable and cannot ``run away`` like conventional feed-back devices.
- Research Organization:
- Electric Power Research Inst. (EPRI), Palo Alto, CA (United States)
- Sponsoring Organization:
- Electric Power Research Inst., Palo Alto, CA (United States)
- OSTI ID:
- 150965
- Report Number(s):
- EPRI-TR-102924-Vol.1
- Resource Relation:
- Other Information: PBD: Oct 1995
- Country of Publication:
- United States
- Language:
- English
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