Abstract: In this paper, through the analysis on the current design technology and applications of bypass control systems, the authors pointed out that the traditional sequential programming design technology tends to complicate the operation process of the bypass control functionality and the system does not have sufficient fault tolerance. Therefore, the object-oriented programming technology is introduced into the whole process control design for bypass systems. Taking the bypass startup process for example, the abstraction analysis on the whole process control is conducted. According to the two important attributes defined, i.e., pressure and valve position, the bypass status is divided into different object regions with the overload methods constructed. Finally, the SAMA diagram of the control system is implemented to illustrate the control strategy. The bypass whole process control is then realized in the DCS control system of a 1 000-MW unit. The operation of the bypass system indicates that by virtue of the object-oriented programming technology, the bypass whole process control system is simple but practical with high fault tolerance and robustness.

Key words: object orientation, bypass system, startup, control strategy, fault tolerance