Study On The Vibration And Noise Of Dry-type Amorphous Alloy Transformer Under DC Bias

In the distribution network,30%to60%of the total loss is transformer loss, and50%to80%of the transformer loss is no-load loss, therefore, it is quite necessary to increasethe proportion of energy-efficient transformers in the distribution network. The core ofamorphous alloy transformer is consisted of amorphous alloy strip whose thickness is0.02mm to0.03mm, about one-tenth the thickness of silicon steel, so the eddy current lossis much less than that of silicon steel transformers. But amorphous alloy strip is thin、brittleand sensitive to mechanical stress, so the noise is greater than that of silicon steeltransformer. In actual operation, DC bias would increase the noise and vibration, so thestudy on noise and vibration of amorphous alloy transformer is very useful for its spread inthe distribution network.Firstly, in terms of magnetic field, the flux density relationship between core columnand yoke is analyzed through theoretical analysis, choose the suitable core flux densitybinding properties of amorphous alloy material. The flux density in core column and yokewas calculated by using FEM software, and compare with the theoretical result, whichvalidate the effectiveness of the calculation method. Then the flux density at differenttimes is calculated by equivalent magnetic circuit method and FEM, compare the resultsand study flux density changes with time flies.Secondly, in terms of structure, the global modal of amorphous alloy transformer iscalculated. On this basis, harmonic response is calculated and the displacement-timeresponse is obtained. Aimed at the large displacement zone, methods like adding L glutenand十gluten are proposed, and calculate the contribution to decrease noise and vibration.Finally, the impact to amorphous alloy transformer by bias current is analyzed.Through flux density simulation analysis, the rule between flux density and bias current isobtained, the change of flux density at different position and no-load current underdifferent bias current are also obtained. The impact to vibration and noise by bias current isstudied by FEM method. Based on the maximum permissible sound pressure in the stategrid corporation purchasing standards, the allowed bias current is calculated.