Research On Ultrasonic Imaging Detection Method Of Transformer Internal Structure

Transformers play an important role in the power system and they are important equipment for substations and power plants.It is very important to the power system when they are safe,stable and efficient operation.In recent years,with the increase of voltage level and the capacity of system,the tasks undertaken by the transformer are getting heavier.There are many failures and one of most damaged failure is internal structural failure.Therefore,it is important to carry out research on fault detection methods of transformer internal structure.After studying the existing winding deformation detection methods at home and abroad,this paper finds that most of the detection methods are offline detection of transformer winding deformation,which greatly increases the time and economic cost of the detection,and it is impossible to determine the specific location of the winding deformation.And severity.Therefore,this paper studies the method of detecting the internal structure of the transformer by applying ultrasonic imaging detection technology.This method can realize the non-destructive online detection of the internal winding deformation of the transformer.The problem of increased time and economic cost can also clearly identify the specific location and severity of winding deformation,effectively improving detection efficiency and accuracy.The main research contents and results of this article are as follows:The internal structure of the transformer and the causes and harms of the winding deformation failure are studied;the nature and propagation characteristics of the ultrasonic wave are analyzed,and it provides a basis for its application in the detection of the internal structure of the transformer;Positioning,in order to avoid mutual interference between the transmitting channel and the receiving channel of the transducer,an ultrasonic receiving transducer is used to receive the acoustic waves emitted by the two adjacent transmitting transducers,which greatly improves the receiving accuracy and also increases the conversion accuracy.Energy efficiency.In order to improve the performance of the ultrasonic transducer,its structure is designed,and the material of important components is selected so that it has higher electromechanical conversion efficiency and can effectively reduce the degree of sound wave diffusion and attenuation;according to the electromechanical conversion relationship The equivalent circuit of each part of the transducer is obtained with the equation of motion,and the equivalent circuit of the entire transducer is derived through the KLM equivalent circuit model.The frequency response characteristic function of the transducer is determined,and the frequency of the ultrasonic transducer is determined.The response characteristics are tested,and the results show that the frequency response characteristics of the transducer are good.Design the imaging system of transformer internal structure,including hardware circuit design and signal processing imaging display research;thehardware circuit includes ultrasonic transmitting circuit and receiving circuit with STM32 as the control core.The designed circuit is verified by simulation software and cooperates with The A / D conversion circuit and the FIFO data buffer circuit complete the conversion and buffering of the received data type.The signal processing part reads the data received by the ultrasonic transducer by establishing serial communication,and processes the read data to realize the imaging display of the internal structure of the transformer through B-scan technology.Finally,the ultrasonic imaging is detected by experiments.The method has been verified,and it can be concluded from the experimental results that the detection method can realize the imaging contour display of the transformer winding and determine the deformation position.