Research on Overvoltage Reconstruction Based on Onboard Voltage Transformer

During the operation of electric multiple units, the transfer characteristics of on - board voltage transformers exhibit non - linear characteristics from DC to 5MHz. This characteristic directly results in inaccurate overvoltage currently obtained from electric multiple units, making it difficult to meet the requirements of precise monitoring. To solve this problem, this paper uses the impulse response method to measure the transfer characteristics of the voltage transformers, and adopts the voltage inversion method to analyze and invert the overvoltage of the transformers, thereby obtaining accurate overvoltage. Based on the actual circuit structure of the voltage transformers in electric multiple units, experiments were carried out to reconstruct the voltage signals on the low - voltage side of the voltage transformers. The results show that the similarity between the inverted waveform and the actually measured waveform is as high as 0.973, and the relative error is significantly reduced to 1.85%. This indicates that the voltage inversion method can effectively reduce the errors caused by the non - linearity of the voltage transformers due to the high - frequency components in the overvoltage signals, which is of great significance for the overvoltage monitoring of electric multiple units.