SYNSIM-a simulation model of a cogeneration plant, for stability analysis and augmentation

In 1994, several Syncrude Canada Ltd. and University of Alberta personnel began the development of a computer simulation model of the Syncrude Utilities steam and electrical plant. Motivation arose out of a concern regarding dynamic stability of the steam header system under upset conditions such as tie line or turbine trips. The model was developed from physical principles and includes all boilers, steam headers, letdowns, turbogenerators and electrical system, and the feedwater system. This large nonlinear simulation model (SYNSIM) has subsequently been used to identify sets of lower-order transfer functions that provide linear multivariable system approximations to the plant under various operating conditions and balances. Using these sets of linear models, well-known methods for designing optimal multivariable controllers were used to design a stability augmentation system for the plant. Its purpose is to improve the stability margins for the oscillatory response modes of the current plant, without replacing or interfering with the existing control system. The augmented system has been tested using SYNSIM, with encouraging results.