Abstract: Taking the 300MW unit of Wangting Power Plant, which was put into operation in the 1990s , as example, the problems existed in DCS, such as that the devices were aged, the reliability of the system was lowered, the standby circuit cards supply was halted and so on, were analyzed. The reformation scheme of the DCS and the concrete implementation process during the unit overhaul in 2010 were introduced. The successful experiences obtained in DCS reformation processes, which included the software function optimization, the digital electrohydraulic control program porting, the construction debugging and others, were summarized. Aiming at the encountered problems, the solutions were proposed, which can be used as reference for similar units in DCS upgrade reformation.

Key words: thermal power plant, distributed control system (DCS), WDPF system, Ovation system, code conversion, graphics conversion, database conversion, upgrade reformation