The advancement accomplished in power systems over the last decade has enabled the extensive integration of renewable energy sources. It has resulted in enhanced efficiency and reliability of the system by meeting the load demand from small, local sources known as distributed generators (DGs). Consequently, this has led to the concept of microgrids (MGs). Nevertheless, there are operational challenges such as bidirectional power flow, fluctuations in fault current level, and protection issues such as blinding, false tripping, and unintentional islanding. Synchronous generator-based distributed generators (SGDGs) may experience a loss of synchronism across the generators due to undesirable events, such as abrupt changes in demand or faults. Similarly, voltage instability concerns may arise with inverter-based distributed generators (IDGs). This paper provides a thorough review of the concepts of critical clearing time (CCT) and grid code compliance in relation to SGDGs and IDGs, respectively. It provides a comprehensive analysis of the existing literature on several protection strategies used for reducing the adverse effects of DG integration. It highlights the characteristics, benefits, and constraints of these schemes. Finally, this paper presents the conclusion and outlines the potential areas for future study in the field of protective relaying methods, specifically addressing the issues posed by current power systems.