Nonlinear thyristor-controlled static VAr compensation

Power systems must be carefully controlled in order to maintain an acceptable power supply quality. Advances in power electronics and control technology have introduced powerful tools to power utilities, and more recently, the concept of flexible AC transmission systems (FACTS) has evolved. One of the major components of the latter is the thyristor-controlled static VAr compensator (SVC). In this paper, a nonlinear feedback method based on differential geometry theory is employed to derive a novel control approach for static VAr compensation (SVC)'s. The paper first constructs the nonlinear model for the power system with SVC control. Special emphasis is placed on the modelling of the thyristor-controlled devices such as the thyristor controlled reactor (TRC). The conditions to algebraically transform the nonlinear model to a linear system are then verified. The linearized model is obtained by feedback linearization, and optimal SVC control laws are then derived for power system stability improvements. The paper concludes by presenting some interesting simulation results.<
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