Prediction method of successive commutation failure for multi-infeed high voltage direct current systems under fault of weak receiving-end grid

Abstract

The complex interactions between AC/DC systems and different line-commutated converter-based high-voltage direct current (LCC-HVDC) expand the effect of commutation failure (CF). The rapid prediction of CF is crucial in ensuring the stable operation of such systems. The simultaneous CF caused by grid fault has received widespread attention in recent years. However, the coupling between the LCC-HVDC with CF and the adjacent normal LCC-HVDC is not considered. When the state of the main circuit suddenly changes and the control system subsequently starts, the LCC-HVDC with CF inevitably produces an effect on the adjacent LCC-HVDC through the coupling of grid voltage. This study describes a new phenomenon, where the former produces a successive CF in the latter under the fault of weak receiving-end grid. The dynamic reactive power characteristics of inverter station and the induced mechanism of successive CF are analyzed. And the dynamic reactive power model of LCC-HVDC is established. A fast prediction method for successive CF is then proposed by calculating the extinction angle of LCC-HVDC with consideration of the effect of adjacent LCC-HVDC with CF. The proposed method can improve the accuracy of CF prediction in multi-infeed LCC-HVDC systems through theoretical derivation and simulation verification.