Impact Analysis of the Wind-Storage Combined System on the Transmission Line Fault Characteristics of Distance Protection

Wind-storage combined system is an important avenue for development under the current dual carbon target. However, when the transmission line fails, the coupling response between the wind and the energy storage device causes its fault characteristics to differ greatly from those of traditional power supplies. Therefore, this paper aims to investigate the control and low voltage ride through (LVRT) strategy of the wind-storage system, analyze its fault characteristics, and examine its impact on distance protection. The theoretical analysis indicates that the fault current amplitude of the wind-storage combined system (WSCS) is insignificant compared to the source system, and its frequency is offset from the power frequency. This offset causes the measured impedance value of the traditional distance protection to deviate from the actual value, resulting in rejection issues. Finally, a refined WSCS model was constructed in PSCAD/EMTDC to validate the analysis.