Characteristic Research And Program Development Of Noise With Large Power Transformers

As an important technical parameter,transformer noise has become the focus of attention.Taking a 110 k V and 220 k V power transformer products as test models,this paper carries out no-load noise tests under different voltages,load noise tests under different currents and noise tests under different DC bias,in order to obtain the noise level and spectrum characteristics of transformers,and proposes noise reduction methods according to the noise characteristics of transformers.At the same time,on the basis of experience and theoretical analysis,a transformer noise calculation software is developed to effectively predict and evaluate the noise level of transformer in the design stage.Firstly,based on the analysis of transformer noise research methods,noise propagation and harmonic characteristics,no-load and load noise experiments with two 220 k V large power transformers are carried out.Through no-load test of 310MVA/220 k V transformer,the sound level and spectrum characteristics under different rated voltage percentages are studied,and through load test of 515MVA/220 k V transformer,the sound level and spectrum characteristics under different rated current percentages are studied.By no-load and load test data,the characteristics and rules of noise under different voltage and current are analyzed,as well as the main frequency components with obvious performance.Secondly,the principle of different types of DC bias wiring is briefly analyzed,and two transformer noise tests under different DC bias are carried out.The noise characteristics and rules under different DC bias are analyzed.At the same time,the spectrum characteristics and main frequency components under DC bias are also analyzed.Thirdly,according to the design structure characteristics and noise characteristics of power transformer,the noise reduction measures and methods are put forward.It mainly includes the selection of material with silicon steel sheet,the setting of magnetic density,the simulation calculation of vibration of transformer,the control of clamping force of core,the use of absorber cushion for body,the adoption of sound insulation structure for tank,and the correct selection of cooling fan.Finally,on the basis of introducing the characteristics of VB language,the work flow and development content of transformer noise calculation program are mainly introduced.The main contents of software include: the calculation of transformer itself noise,the calculation of transformer noise,the calculation of natural cooling noise,the calculation of fan cooling noise and the calculation of transformer load noise.And taking 515MVA/220 k V test and research products as an example,the reliability of program calculation is verified.The results show that the accuracy of transformer noise calculation program is high,and it can fully meet the needs of Engineering.Besides,the program operation is simple and clear,and easy to master.