Research On Partial Discharge Location Technology Of Transformer Based On Ultrasonic Method

In the actual operation of electrical equipment,the state of the equipment itself is directly related to the safety and stability of the entire power system.Among them,the safety and reliability of High-voltage power equipment are highly required,but the insulation problem is a fatal problem of High-voltage power equipment,leading to the partial discharge of the transformer and seriously affecting the safety of the power system.As a kind of High-voltage power equipment,the partial discharge positioning technology for power transformers has become a research hot spot.In this paper,based on the ultrasonic method,the localization methods of partial discharge outside the transformer and partial discharge inside the transformer are studied deeply.The main tasks are as follows:Firstly,the research status and progress at home and abroad as well as the significance of PD localization of the transformer are analyzed.Secondly,based on the ultrasonic time positioning method,the localization technology of single partial discharge outside the transformer is studied,and the localization technology of 500 k V asbestos substation GIS equipment is analyzed,and the attenuation characteristics of the ultrasonic wave in the air are obtained.Based on the vibration amplitude difference positioning method,the realization of the transformer external PD amplitude difference positioning is studied and the realization method is designed.At the same time,based on the ultrasonic time positioning method,the partial discharge positioning analysis of a single partial discharge in the transformer interior is studied.Two practical engineering experiments are carried out.The partial discharge positioning using the time difference method is studied in the sealed space.The attenuation property of the ultrasonic wave in transformer oil and the refraction and transmission properties of the ultrasonic wave are analyzed.Based on the research of vibration amplitude difference localization,the method of single partial discharge localization in the transformer is studied,and the experiment of partial discharge localization in regular sealing construction is carried out by the method of vibration amplitude difference.Besides,the classification of noise during ultrasonic testing and the methods to reduce noise interference are analyzed.In the actual system,a noise reduction method is proposed to deal with the possible interference factors when the ultrasonic wave is used to locate the single PD position.The existing positioning theory is verified by combining with the actual work,and a set of simple positioning scheme is given while absorb useful ideas and effective methods.Finally,a more universal optimization scheme is proposed.