Differential Protection for Double-Ended Weak-Infeed Transmission Lines Based on Time-Domain Integral Value of Traveling Waves

For MMC-HVDC systems connected with PV power plants, the converters on both sides of the AC transmission line will adopt different fault-ride-through strategies, making the fault characteristics of the line complicated. Under complex fault characteristics, traditional protection schemes such as current differential protection face challenges such as the reduced sensitivity. In this paper, a differential protection scheme is proposed based on fault traveling wave theory, and an auxiliary criterion using wavelet transform is proposed to ensure accurate identification of fault interval while achieving high sensitivity. The proposed scheme has been verified in PSCAD/EMTDC, and simulation results show that the proposed method is a highly sensible protection scheme suitable for double-ended weak-infeed lines between large-scale renewable energy and MMC stations.