Characteristic Analysis and Risk Assessment for Voltage–Frequency Coupled Transient Instability of Large-Scale Grid-Connected Renewable Energy Plants During LVRT

The voltage-frequency coupled transient stability and risk assessment issues of weak grid-connected large-scale renewable energy plants (REPs) during low voltage ride through (LVRT) have received little attention to date. The shape and mechanism of voltage-frequency coupled transient instability during LVRT are investigated in detail by the voltage-vector-triangle graphic (VTG) method utilized in this article, which avoids complex mathematical...