The insulation structure of the outgoing device area of UHV converter transformer and its' long-term aging performance

The insulation structure of the outgoing device area of UHV(Ultra High Voltage) converter transformer is complex and huge. It bears the effect of high current and high voltage for a long time. It will cost a lot to carry out on-site operation and maintenance test. At present, digital twin technology is becoming more and more perfect, and gradually introduced into the power industry from automobile, aviation and other manufacturing industries. Based on this, this paper introduces the digital twin technology into the high-end power equipment of UHV converter transformer. Considering the complex structure of converter transformer and its outgoing line device and converter bushing area are important typical accessories, this paper focuses on the construction of digital twin 3D model in this area, and carries out on-site operation and maintenance simulation test and high current functional response analysis under high voltage load. The digital twin model of the outlet device area is constructed according to the electro-thermal coupling physical field simulation model. The electro-thermal sensor is used to monitor the on-line voltage and current waveform in real time, and the interaction between the on-site operating parameters and the loading data of the digital twin model is realized. On the other hand, the intelligent extraction and identification of material area in the digital twin model is realized, and the material parameter performance can be changed according to the physical field environment, so as to adapt to the structural design and performance evaluation of different operating environments. Further, in order to analyze the relationship between the internal transient temperature of the converter bushing and its short-term current carrying capacity and long-term aging performance, the cyclic transient variation law of the hottest spot temperature of the high-voltage bushing is determined by fitting the diurnal cyclic load through the step load curve and combined with the thermal network. The electrical and thermal stresses are obtained by using the regional digital twin model of the outgoing device of the converter transformer. The long-term aging performance of the converter bushing is analyzed according to the classical ZHURKOV and CRINE electro-thermal combined aging model. This paper focuses on the 3D construction of digital twin model in the outgoing area of converter transformer. Its research method can be extended to key components such as converter body winding structure, oil paper insulation area and on load switch. The research results of this paper can provide theoretical guidance and technical reference for the insulation structure design of converter transformer body, especially for the structural design and operation maintenance of outlet device area, and can provide some theoretical guidance for on-line analysis of short-term current carrying capacity and long-term aging performance of converter transformer outlet device area.