Abstract: Addressing the issue of inconsistent overload setting values for the excitation system windings of Units 1 and 2 in a 1150 MW turbine generator at a nuclear power plant's Phase I, this study analyzes the coordination characteristics of the time-inverse/anti-inverse over-excitation limits, excitation-side overcurrent protection, and generator main excitation winding overload protection based on the rotor winding overload capability and relevant national standards. The findings indicate that the anti-inverse over-excitation limit exhibits mismatched coordination with subordinate protections in the 1.1~1.2 rated excitation current range, potentially triggering false tripping. Multiple time-inverse overcurrent protections in the excitation system suffer from hierarchical confusion and lack coordination logic, failing to align with winding thermal accumulation processes and unable to meet the thermal safety boundary requirements for generator windings under high-current conditions. While the time-inverse over-excitation limit achieves effective coordination with subordinate protections, the upper current limit aligns with the generator's strong excitation capability and thermal tolerance requirements. Final recommendations include adopting a unified over-excitation limit mode, optimizing protection configurations, and refining anti-inverse curves as engineering measures to provide technical support for excitation system protection setting and secure stable operation of nuclear power units.