Research On Multi-frequency Ultrasonic Testing System For Power Transformer Oil Parameters

Transformer oil plays an important role in insulation,heat dissipation and arc suppression in oil-immersed power transformers.The performance of transformer oil decreases due to impurity pollution and aging of transformer oil,which causes hidden dangers to the normal operation of power transformer.However,the existing transformer oil detection methods have the disadvantages of tedious detection process,single oil performance parameters and low detection efficiency.Therefore,a power transformer oil detection method based on multi-frequency ultrasonic technology is proposed.A power transformer oil parameter detection system is designed and manufactured to realize fast and accurate detection of multiple transformer oil parameters.First of all,the principle of multi-frequency ultrasonic testing technology for transformer oil parameters is studied.By analyzing the principle of ultrasonic testing,three common methods of ultrasonic testing are obtained.By studying the fluctuation and atteghnuation characteristics of multi-frequency ultrasound in transformer oil,the relationship between ultrasonic acoustic parameters and transformer oil parameters is obtained,and the technical principle of multi-frequency ultrasonic testing technology for transformer oil parameters is summarized.Secondly,based on the research of the multi-frequency ultrasonic detection method,a multi-frequency ultrasonic detection hardware system for transformer oil parameters is designed and fabricated.The measurement methods of ultrasonic velocity and attenuation coefficient are studied,and the design idea of hardware system is determined.The ultrasonic transducer and data acquisition card are selected,and the driving circuit and echo processing circuit of multi-frequency ultrasound are designed.Thus a hardware system of multi-frequency ultrasonic testing for transformer oil parameters is formed.This system can realize the transmission of different frequencies of ultrasound and the collection of echoes.It can acquire the parameters of ultrasonic speed and attenuation coefficient,and transmit the detection data to the upper computer software,thereby realizing the efficient and accurate detection of transformer oil parameters.Finally,a transformer oil parameter detection software system is designed and developed.A multi-frequency ultrasonic testing model for transformer oil parameters is established by using BP neural network which is optimized by improved grey wolf algorithm training samples.Based on this testing model,a software system for transformer oil parameter detection is designed and developed,which can process multi-frequency ultrasonic testing data,quickly generate the test results of transformer parameters,analyze the test results and give the operation status of transformer oil.The system realizes the efficient and accurate detection of the transformer oil parameters,which can play a good guiding role in the actual maintenance work.