Research on Measurement Method for DC Bias State of Converter Transformer

Aiming at the complicated causes of transformer bias in converter stations, this paper improves the technical means for monitoring the DC bias state of converter transformers. First, four different types of magnetic bias can be identified by monitoring the conductor surface magnetic field on the neutral point down conductor of the converter transformer. Secondly, the vibration acceleration data of the transformer is obtained by arranging an acceleration measurement unit on the transformer shell, thereby identifying the magnetic bias vibration state of the transformer. Finally, by monitoring the magnetic flux leakage of the transformer, the bias magnetic flux leakage characteristics of the transformer are obtained, and an early warning of risky components is provided for transformer maintenance. The method of this paper can detect the abnormal DC bias magnetism of the converter transformer in time, and provide technical reference for the safe operation and inspection and maintenance of the converter transformer.