Establishment of Low Voltage Ride-Through Curves and Stability Analysis with High Photovoltaic Penetration in Power Systems

Abstract

In this study, a low voltage ride-through (LVRT) curve was produced to facilitate stable operation of solar power systems when connected to electric grids in an extensive scale. The procedure for establishing a LVRT curve was as follows: The power flow was first simulated, after which various three-phase short-circuit fault cases were simulated to perform steady-state and transient stability analyses. After the lowest voltage, critical clearing time, and other factors were identified, a LVRT curve was established for a solar power system to better accommodate regional demands, reduce the probability of solar power system tripping caused by system failures, and maintaining stability. To ensure that the parameters used in this study complied with relevant energy policies, the IEEE 39 Bus power system was used as the electric grid and verifications performed using actual Taiwan Power Company systems. The Taiwan Power Company's 2025 data were used with peak and off-peak systems operating during the summer and winter, respectively. The solar power systems were connected to electric grids in central and southern Taiwan, and regulations stipulated in the guidelines were referenced for subsequent analyses. Whether results satisfied related power regulations could thereby be determined. A LVRT curve was established based on the real power, reactive power, voltage, and system rotational angles measured during system failures. The simulation results showed that no solar power system tripping occurred, and system stability was maintained. The LVRT curve proposed in this study can be referenced by countries worldwide for the establishment of LVRT curve.