Abstract: The design requirement and application situation of the synchronizing circuit under 3/2 connection mode were expounded, in which the synchronization control circuit design, the synchronization AC voltage loop design and the synchronization check test of large generator set under 3/2 connection mode were included. The purpose of this paper is to ensure the synchronizing operation of the units under 3/2 connection mode to be more rational, perfect and security.

Key words: 3/2 connection mode, synchronizing circuit, voltage switchover, synchronization check