Substations represent critical components in electrical power distribution systems that require reliable protection systems and periodic maintenance to ensure service continuity. This research aims to analyze the performance of protection systems and SF6 gas quality at the 150kV Cibubur Substation Bay Cibinong following maintenance activities. The research methodology encompasses measurement of electrical parameters in protection systems, analysis of SF6 gas quality through moisture content testing, purity level assessment, and dielectric strength evaluation, along with operational performance evaluation of switching equipment. Data collection was conducted through direct field testing using industry-standard equipment before and after maintenance procedures. Research findings demonstrate that the implemented maintenance successfully enhanced protection system performance with relay coordination values meeting IEEE standards, while SF6 gas quality showed significant improvement in moisture content parameters, decreasing from unacceptable levels to compliance with IEC 62271-303 standards. The dielectric strength of SF6 gas also increased, indicating the effectiveness of maintenance processes in restoring equipment insulation function. This research contributes to the optimization of substation maintenance programs and provides recommendations for enhancing the reliability of electrical power distribution systems.