PARALLEL OPERATION OF TRANSFORMER FOR RECTIFIER

摘要

PURPOSE:To reduce high harmonic even at the time of occurrence of trouble on a rectifier, in parallel operation of transformers for rectifier using DELTA and Y combination for connection on secondary side of the transformers, by conducting selective operation of the transformer in the case of occurrence of trouble on the rectifier. CONSTITUTION:A transformer T1 has Y connection on the secondary side, transformers T2 and T3 have DELTA connections on the secondary sides, and there is a difference in phase on the secondary side by 30 deg. between the transformers T1 and T2. Outputs of the transformers T1, T2 and T3 are connected to static constant- voltage constant-frequency power source devices R1, R2 and R3, respectively, operated in parallel and put into an AC load. Even if the device R2 or the device R3 were to be in trouble, during the operation of R1, 12-phase rectification is conducted by the transformers T1 and T2 or the transformers T1 and T3. When the device R1 stopped operating due to occurrence of a trouble, switches S1 and S2 are opened and S3 is closed, the transformer T1 keeps supplying power to the device R2 for continuation of operation, and by combination of the transformers T1 and T2 the 12-phase rectification is conducted, and thereby, high harmonic is reduced.