Enhancement of the inductive operating range of a TCSC in the High-Voltage Grid using a mechanically switched series reactor

This Paper shows one of the possibilities to use Vacuum Circuit Breakers (VCBs) in flexible AC transmission systems in the High-Voltage Grid. A mechanically switched reactor, which is series connected to a TCSC in order to enhance the inductive working range is investigated. VCBs are used as switching elements as they can be switched more often without maintenance compared to other circuit breakers. Nevertheless, the switching frequency is strongly limited by their mechanical properties. In order to extend the application range to faster events like damping of power oscillations, more VCBs are switched in parallel to each other. Hence a higher periodically switching ability could be achieved. In this paper, it could be shown that the mechanically switched series reactor is able to enhance the damping of power oscillations. Furthermore the electrical stress on the VCBs and on the reactors for different simulation cases has been assessed. The simulation is performed with PSCAD.