Abstract: The application of data mining in thermal power plant was introduced. A data mining algorism based on similarity analysis technology was put forward. On this foundation, the unit economical operation pattern data mining system based on the VS2005 platform and the SQL Server 2005 database was developed. The system structure and functions were analyzed, and the design process of main modules of software system was expounded. The system had been applied in practical production data of power plant successfully, the mining result of unit economical operation pattern was obtained, the incremental mining method was realized, and excellent effects were obtained.

Key words: data mining, pattern extraction, thermal power generation unit, incremental mining method