Analysis of the Digital Twin Technology in the Power Equipment from the Perspective of Development and Operation of ±500kV Converter Bushing

Digital twin technology is gradually being applied in the power system, but it mainly focuses on field of power equipment. If we introduce the application of digital twin technology from a comprehensive perspective in the field of power equipment, we will comprehensively analyze typical power equipment such as converter transformers, converter valve towers, and substations, which involve many complex and comprehensive characteristics of power equipment. In view of this, this article focuses on the development of 500kV converter transformer bushing, analyzes the external operating environment of the bushing, and conducts a detailed verification calculation of the net distance of the bushing insulation space. At the same time, infrared thermal imagers, ultraviolet imagers, and high-definition digital photos are used to observe the metal accessories of the 500kV converter transformer bushing in detail. The main reason is the combined effect of voltage and current with rich frequency. This article attempts to analyze the voltage and current waveform at key nodes of the ultra-high voltage converter valve hall from a theoretical perspective, and derive analytical formulas using a 12 pulse rectifier (double bridge rectifier) to obtain the Fourier decomposition results of the actual voltage waveform of the converter bushing: the DC component is 697.6kV, the fundamental frequency is 50Hz, and the peak of the 1-27th harmonic component is THD=46.79%. Finally, this article takes a typical 500kV converter transformer bushing as an example to provide a detailed explanation, including typical parameters of its internal insulation design: number of pole layers=63, length of zero layer pole plate=6762mm, diameter of conductive rod=100mm, length of N-layer pole plate=1730mm, and diameter of N-layer pole plate=385mm. And the model was optimized and designed through this model, and the electric field and voltage distribution of the bushing were studied under eight voltage types: rated voltage (transformer AC+DC), superimposed AC voltage (phase to ground), DC voltage (phase to ground), applied DC withstand voltage (positive polarity, 120 min), test voltage (50Hz, 1 min), lightning impulse withstand voltage test voltage (full wave), and DC polarity reversal test voltage (DC 90 min negative polarity, 90 min positive polarity, 45 min negative polarity). This article focuses on the study of positive and negative 500kV converter bushings and the application of digital twin technology in power equipment operation and maintenance. It has good guiding value and significance for the application of digital twin technology in other power equipment.