Dynamic modeling of high power static switching circuits in thedq-frame

摘要

With the proliferation of static switching circuits in powernsystems, there is a need to understand not only their steady-statenbehaviour but their dynamic interaction with the network as well.nAnalysis is difficult due to the nonlinear nature of switching processesnassociated with such devices. Linear, time-invariant (LTI) dynamicnmodels are needed for standard analytical tools such as eigenanalysisnfor the study of inter-area as well as higher frequency modes of thensystem. To this end, LTI small-signal dynamic models are developed fornhigh power static switching circuits in a synchronous rotatingndq-reference frame. Two conventional devices are chosen for study: anthyristor controlled series capacitor (TCSC) and a HVDC power converter.nThe proposed models are shown to represent the dynamic response of thenstatic switching circuits to nominal changes in operating point. Innparticular, the damping characterizing the dynamic behaviour of the TCSCnis shown to vary significantly with operating point. This accounts fornthe observed responses arising from field tests and simulations but notnaccounted for by the quasi-static model. On the other hand, the dampingncharacterizing the dynamic behaviour of the HVDC converter is shown tonvary little with operating point. The linearized models are validated byndigital time-domain simulation of the nonlinear static switchingncircuits