A Nonlinear Generalized Switching Function Model For SVC And TCSC Devices

抄録

This work presents the application of generalized switching functions to the modeling of Thyristor Controlled Reactors (TCRs). The development of detailed nonlinear and linear analytical models of TCRs are presented. These models allow for the precise analysis of the TCR transient phenomena for a frequency range of up to some tens of Hz. Validation of the models was done by comparing simulated results obtained with the proposed models with those obtained with a traditional electromagnetic transients program (EMTP). The nonlinear model for the TCR was developed using generalized switching functions. Based on this model, a detailed linear model was derived. This linear model allows for the analysis and precise understanding of the behavior of a TCR under small disturbances both in the time and frequency domain. Interactions between voltage controllers of two SVCs in the subsynchronous frequency range were analyzed for a specific example. It was shown that the analytical linear model is a very precise and powerful tool to evaluate such interactions. The model predicts system instabilities, which could not be predicted at all by traditional models. With the proposed model it is possible to design the controllers of SVCs in an integrated form so that the risk of instabilities can be avoided.