A fuzzy control scheme for thyristor controlled series compensation in transients of power systems

A desirable transient stability control scheme should be able to ensure the first-swing stability as well as provide effective damping. This paper presents a T-S model based fuzzy control scheme for thyristor controlled series compensation (TCSC) in power system transients. The nonlinear power system containing a TCSC is modelled as a fuzzy “blending” of a set of locally linearized models. A linear optimal control is designed for each local linear model. Different control requirements at different stages during power system transients can be considered in deriving the linear control rules. The resulting fuzzy controller is then a fuzzy “blending” of these linear controllers. Furthermore, a gradient descent algorithm is put forward to modify the rule truth factors for optimization. For convenient industrial realization of the fuzzy control scheme, a practical approach requiring only local signals is also described. Simulation with NETOMAC software has verified the effectiveness of the fuzzy control scheme