The large-scale integration of renewable energy reduces the voltage support strength of the power system

leading to a decrease in the short-circuit ratio (SCR) and an increase in voltage sensitivity

which exacerbates the risks of voltage and synchronization instability for grid-following (GFL) converters. Grid-forming (GFM) converters

with their strong voltage support capabilities

can enhance system voltage support and stability when deployed with sufficient capacity at new energy stations. However

it is still unclear what specific instability risks necessitate the deployment of GFM converters. Consequently

it is challenging to estimate the capacity of GFM converters required for engineering applications. Therefore

this paper focuses on the AC delivery scenario of new energy bases

addressing the core requirements for the safe and stable operation of GFL new energy stations. It provides estimation for the capacity ratios and overcurrent capability needed for GFM converters. First

it analyzes the instability issues of GFL converters under low voltage ride through (LVRT) conditions and mitigation strategies through self-control optimization

with GFM converters ensuring stable operation of GFL converters under non-LVRT conditions

thereby defining its functional role in AC delivery scenario. Then

based on regulatory requirements

the minimum generalized short-circuit ratio (gSCR) required for GFL renewable energy stations in low-voltage normal operation is estimated. On this basis

the required capacity and overcurrent capability of GFM converters are estimated. Finally

simulations are conducted to validate the methods in this study.