Reduction of vibration noise for amorphous metal alloy core distribution transformer

Abstract

Abstract：To understand the vibration noise behaviors of amorphous metal alloy core distribution transformer (AMACDT), a 10 kVA prototype was tested under no-load and short-circuit conditions, respectively. The vibration characteristics were described when rated voltage was applied to the secondary side, and the primary side was connected with different load resistances. The largest amplitude positions on the upper bracket and tank surfaces were recorded by vibration sensors arranged on the surface. A data-acquisition platform was set up for signal measurement. The vibration amplitude related to frequency was discussed, and experimental results indicated that the position with the largest amplitude accrued in the middle of the upper bracket and tank surface, at phases a and c, respectively. The experimental results suggest that magnetostrictive and electrodynamic forces play a major role in exciting the vibration noise. At the same time, some rib-reinforcements were welded on the upper bracket and tank surfaces to lessen the vibration energy, which reduced the noise. Keywords：distribution transformer； magnetostriction；electrodynamic force；amorphous metal core；vibra-tion； noise transmission Considering the fact that developing countries with huge population are consuming electrical power at everincreasing rates, the role of amorphous metal core distribution transformers(AMACDTs)on energy efficiency and reduction of CO 2 emissions is becoming significant [1] . As AMACDTs have the advantage of low no-load losses compared with orientation silicon-steel distribution transformers(OSDTs), their wide use can have a considerable impact on global energy-saving efforts [2] . However, a high noise level for AMACDTs is inevitable，which is generated mainly in transformer cores and coils by magnetostrictive and electromagnetic forces [3] .The primary source of noise in a transformer is the periodic mechanical deformation of transformer cores and coils under the influence of fluctuating electromagnetic flux [4] . The vibration of a transformer core is a result of its varying magnetostrictive strain by two times alternating frequency [5] . The periodic magneto motive force may cause the core laminations to strike against each other and produce noise. Moreover, the periodic mutual force can cause the current-carrying coils to vibrate if there are any loose turns therein [6] .During operation, cores and coils transmit vibrations to the transformer bracket surface through structureborne. The vibrations can also reach the tank surface, at positions where the cores and coils are attached and the space between the AMACDT body and tank, respectively. The vibration on the tank surface eventually radiates the noise into the exterior air. Yang [4] gave a review of the generation and transmission of vibration and noise in a transformer.Previous researchers [7] have investigated how to reduce the noise resulting from cores. Yao et al [8] and Somkun et al [9] show that vibration analysis of transTrans. Tianjin Univ. Vol.21 No.4 2015 -...

Acceleration Data Acquisition and Analysis Method of Shaking Table Test

“…9). The damping ratio is obtained by using half power bandwidth method [6]: 2.06%. This can be judged in seismic wave loading 0.75-25Hz range of the model, frequency confused will not occurred because of the model self-vibration.…”

A novel method to check the axial tilt instability of the rectangular winding of the amorphous alloy transformer

“…The amorphous alloy transformer with its core made of an amorphous alloy strip can effectively reduce the no‐load loss and no‐load current of the transformer . Currently, the amorphous alloy transformer winding can be made only in the rectangular structure, so electromagnetic theory for the circular winding structure does not apply to the amorphous alloy transformer, including the short‐circuit check model of the transformer winding.…”