In this paper, an experimental investigation of active control of noise transmission through the transformer tank was conducted. A digital structural acoustic control approach was adopted in which the active constrained layer damping (ACLD) panels were directly mounted on the tank shell as actuators to suppress the noise transmission. This work is focused on a concise actuator location strategy for engineering purposes, where only a few actuators are needed to locate on the anti-node of (1, 1) order radiation mode with a high control authority. Configurations of the ACLD actuators’ numbers and positions were discussed in numerical simulations in finite element models with fully "acoustic-structure" coupling. Experiments with an adaptive feedforward control loop were carried out on an actual operating 35kV transformer. Active control was implemented on transformer noise transmission peak of 600Hz, and noise levels were monitored at 0.3 m and 1 m away from the transformer tank shell respectively. Results show that, when 5 dB attenuation of tank shell vibration was suppressed by the actuator position, noise attenuation of 13 dB and 5 dB, respectively, can be simultaneously observed at monitor positions of 0.3 m and 1 m away from the transformer tank. In particular, enhancement of robustness was observed in the control loop by taking advantage of the ACLD actuators.

active structural acoustic control,Sound transmission,Transformer tank,Active constrained layer damping