Upgrades at a critical substation addressed aging equipment and outdated protection, control, and monitoring systems to improve reliability and meet current standards. ISG provided detailed design for a comprehensive replacement and modernization effort, including installation of one 138kV breaker, four disconnect switches, three surge arresters, two current transformer sets, and upgrading relay, SCADA, and battery systems. The work strengthened fault response and positioned the facility for long-term, dependable operation.