With the growing integration of renewable energy and the reduction of inertia, ensuring frequency security has become a crucial issue in the planning of power systems that rely heavily on renew abIes. To determine the maximum proportion of renewable energy that can be accommodated while meeting frequency security requirements, this paper examines three types of disturbance events: load increases, faults in renewable energy equipment, and faults in synchronous generators. To achieve this, we conducted experiments on the IEEE 39-bus test system using DIgSILENT PowerFactory simulation and employed the static generator model to represent renewable energy equipment that is connected by converters. Our simulation results indicate that the acceptable maximum proportion of renewable energy varies depending on the type of disturbance considered. Specifically, the maximum proportion is 53.35%, which satisfies frequency security requirements as measured by maximum frequency deviation, steady-state frequency deviation, and the rate of change of frequency.