Influence of Permeability on Voltage Stability of PV Inverters through LCC-HVDC System

According to China’s carbon peak and carbon neutrality strategy, the utilization of high voltage direct current (HVDC) transmission for renewable energy transfer has become a focal point for large scale renewable energy development and utilization. As the sending end power grid of HVDC weakens gradually, there may be voltage stability issues, the voltage of the photovoltaic (PV) inverter is too low to operate normally. This article first provides definitions for the differences in short circuit ratios (SCR) at the three interfaces of the three ports network composed of a photovoltaic power station, LCC-HVDC and the AC grid. Next, the critical short circuit ratio (CSCR) expression for the PV inverter point of connection is derived. Finally, based on MATLAB simulation, the accuracy of the CSCR expression is verified.