Fast and predictive HVDC extinction angle control

This paper proposes unique DC control strategies to prevent dynamic commutation failures during and following faults, and to obtain better recovery from the faults. The strategy is based on an idea of sine-cosine components detector in which AC voltages are detected fast in terms of two components on the rotational reference frame synchronized with an AC system frequency. The controller quickly predicts a necessary control angle according to the magnitude, the phase angle, and involved harmonics that are calculated from these two components. The validity and effectiveness of the controller are confirmed through the EMTP simulations. The DC simulator results using the fabricated controller confirm the EMTP simulations.