Study on identification of winding material in distribution transformer based on computed tomography

In recent years, the manufacturing industry of distribution transformer (DT) in China develops rapidly with high competition. The DTs with aluminum winding replaced by copper winding has been appeared, which increases the risk of security and stability operation for power grid. It is significance to study on winding material identification method, which can guarantee the benefit of the investor, and ensure the reliability of power supply. The reasons for using aluminum winding instead of copper winding without marks are analyzed, and the limitations of the current identification methods are analyzed. The identification of winding materials based on computed tomography is put forward. The attenuation law of X-ray in different conductors is analyzed, which can be used to identify the winding materials. The construction scheme of CT detection room for DTs is proposed. The feasibility, validity and sensitivity of the proposed method are verified in practice, and it is widespread applied.