Study On Vibration And Noise Of Transformer Used In Photovoltaic Power System

With the continuous development of human society and economy,the energy shortage and environmental pollution problems have become more and more serious,which leads to the development and utilization of renewable new energy sources becoming a major topic for human’s sustainable development.Due to the advantages of solar photovoltaic power generation,it has become one of the hot topics in the field of the research and application of new energy.The transformer is an important electrical equipment of PV grid-connected power generation system,so it is necessary to analyze and study their performance.Photovoltaic array’s output is DC,which must be reversed to AC by the inverter to run in parallel with the power grid through the step-up transformer.However,when the inverter converts the DC generated by PV modules into the AC,it will introduce DC and harmonic components into the system,which not only reduces the power quality,but also increases the vibration and noise of the transformer,especially for the amorphous alloys transformer.In addition,the DC and harmonic components will also increase the no-load loss of the transformer.The amorphous alloy transformer is widely promoted by China because of its no-load loss is only 1/5 of the commonly used silicon steel transformers,which leads to the increasing of the amorphous alloy transformers’ s number in the photovoltaic power generation system.Therefore,this article takes the amorphous alloy transformer as the research object,and focuses on the vibration and noise problems of transformers for photovoltaic power generation systems.Based on the transformer’s vibration and noise’s theory analysis and Matlab/Simulink’s system simulation analysis results of photovoltaic power generation transformers,a high-impedance amorphous alloy transformer for photovoltaics with a rated capacity of 2500 kVA and a transformation ratio of 10000/480 kV is selected as the key research object.First of all,the magnetic field characteristics are emphatically analyzed to lay the foundation for subsequent coupling research.Then,using the finite element multiphysics coupling software COMSOL,couples and analyzes the electric field,magnetic field,structural force field and sound field of the transformers for the photovoltaic power generation system,mainly study the vibration and noise of transformer core under no-load condition,at the same time,by comparing and analyzing the results of each physics field,the general conclusions about the influence of the magnetostriction of the iron core and the DC component of the photovoltaic system on the vibration noise of the transformer are obtained.Then,taking into account that the resonance may cause the abnormal vibration of the transformer,so the core’s modal analysis is made,and core’s the first ten natural modes and their frequencies are obtained.Finally,the vibration and noise experment of a three-phase five-column amorphous alloy transformer is conducted and it verifys the accuracy of simulation analysis.