A Measurement Method for Residual Magnetism in Power Transformers Based on the Excitation Voltage Integration Method and Its Implementation

Power transformers are critical components in transmission and distribution systems, after a direct circle test,the core of the transformers will be magnetized. If this residual magnetism reaches a certain level, it may affect the transformer's operation and could even lead to damage to the transformer or surrounding equipment. Thus, demagnetization testing is conducted before transformer commissioning to mitigate the effects of residual magnetism. This paper presents a transformer residual magnetism measurement method based on the excitation voltage integration technique. An analysis instrument was developed that integrates this method into a transformer demagnetization analyzer, enabling real-time assessment of residual magnetism levels and effective removal of residual magnetism in transformers. Practical applications have shown promising results, offering a reliable means to address residual magnetism in transformers.