This paper reviews methods used for calculating Critical Clearing Time (CCT) in power systems. Most existing CCT studies focus on power systems dominated by Synchronous Generators (SGs). In contrast, the impact of Synchronous Condensers (SCs) on CCT in modern power systems remains less explored. SCs are increasingly deployed to provide system strength and to support higher penetration of inverter-based resources (IBRs). System strength is referred to ability of power systems to maintain stable voltage waveforms under normal conditions and following disturbances, especially in modern powers system with high penetration of IBRs, in Australian power system industry. This paper compares the impact of CCT for the SCs and SGs using a simplified Single Machine Infinite Bus (SMIB) model. The simplified framework enables a direct and transparent comparison without unnecessary modelling complexity. The study also investigates the influence of the inertia constant of SCs on power system CCT. In recent years, it is widely assumed that higher inertia from SCs may enhance system stability as SGs are progressively displaced by IBRs. In traditional power systems, inertia was implicitly linked to demand. During high load conditions, more SGs were dispatched, resulting in higher system inertia. Under light load conditions, fewer SGs were online, and system inertia was correspondingly lower. As SCs are operated for system strength, they are in service regardless of system load. As a result, higher inertia is likely to be present under light load conditions. This can affect damping and increase the magnitude of active power swings, particularly in low-demand scenarios. Future work will investigate the broader impact of high-inertia SCs on system stability, dynamic performance and damping in modern power systems.