Analysis of the Transmission Characteristics of ±500kV Metal-Enclosed DC Potential Transformer

In order to obtain the transfer characteristic of DC potential transformer and improve the measurement accuracy, this paper takes the ±500kV metal-enclosed DC potential transformer as the research object and studies the changing rule of the transfer characteristic of ±500kV metal-enclosed DC potential transformer from typical aspects , such as production errors, stray parameters, ambient temperature, and output channel damage. The findings indicate that the errors in resistance production, ambient temperature variations, and the extent of output channel damage contribute to changes in resistance, which subsequently result in measurement errors for DC potential transformers. The relationship among these three factors and their impact on resistance change is as follows: output channel damage>ambient temperature>resistance production error. In the range of 18°C to 32°C, the temperature will not cause the measurement accuracy level of DC potential transformer to decrease. The stray capacitance mainly leads to the measuring error of AC voltage, that is, the measuring error of AC voltage increases about 0.4% when the stray capacitance increases by 5pF. The output channel mainly leads to the measurement error of direct flow, that is, as long as the output channel is damaged, the measurement result will not meet the standard requirements. When the resistance-capacitance matching relationship is destroyed and the system voltage changes, the DC voltage divider measurement results will have a short transition process, and the DC measurement error at the transition moment is seriously deviated from the normal value.