A novel high-sensitivity time-domain current differential protection scheme for renewable power transmission system

Abstract

Integrating large-scale renewable energy sources in modern power systems has altered fault characteristics, resulting in the performance degradation of conventional current differential protection. This paper proposes a novel high-sensitivity time-domain current differential protection scheme. The proposed scheme utilizes the Bergeron model to eliminate the impact of the distributed capacitive current. Furthermore, the Bergeron model error is analyzed theoretically during normal operation, and an algorithm is designed to identify and adjust the α- and β-mode line parameters. Additionally, novel internal fault criteria are presented to mitigate the negative impact of the 0-mode line parameter error. Compared to traditional frequency-domain approaches, the proposed method can more accurately and rapidly distinguish internal and external faults, while reducing the dependency on precise line parameters. Eventually, a VSC-HVDC sending-end grid model consisting of 100% renewable power generations is established using PSCAD/EMTDC software. Simulation results confirm that the proposed protection scheme exhibits exceptional performance in terms of operating speed, sensitivity, and tolerance to fault resistance and noise.