Research on distribution characteristics of vibration signals of ±500 kV HVDC converter transformer winding based on load test

The converter transformer is important for the high-voltage direct current transmission system. The distribution characteristics of the vibration signal of the tank are significant for the operation status monitoring and the judgment basis for the fault condition of the converter transformer. However, most present research on vibration detection technology focused on ordinary power transformers rather than the HVDC converter transformers. Moreover, the influence of the special structure and the heat accumulation effect of the load current on the vibration signal distribution characteristics is not fully considered. To solve the above problems, this paper analyzes the intensity distribution of vibration signals at different positions on the tank surface and valve side bushings based on the offline load test. At the same time, to study the influence factors of vibration signal distribution, the influence of current heat accumulation on winding characteristics and transformer oil temperature is analyzed. The results show that vibration intensity is related to location and the load current. And the vibration intensity of the tank surface increases with the time of current flowing through the winding, nevertheless, the vibration intensity tends to decrease near the valve-side bushing. The test methods and research on distribution Characteristics in this paper can provide new thoughts for the optimization of the layout of converter transformer vibration detection sensors, and provide a research basis for the application of vibration signal fault diagnosis methods.