Develop secondary engineering design packages for HV substations (66kV to 500kV), including:Protection & Control schematics (AC/DC schematics, wiring diagrams)Relay coordination settings and philosophySingle-line diagrams and interlocking logicMetering and interface schematicsSCADA & communication architecture (RTU/IED configuration)Selection and application of protection relays (Siemens, GE, SEL, ABB, SchneiderPrepare and review control room layouts, panel GA drawings, wiring schedules, and terminal plansDesign of substation auxiliary systems: AC/DC supply systems, battery sizing, chargers, and LV panelsEnsure compliance with IEC 61850, IEC 60255, IEEE, and customer-specific standardsCoordinate with primary, civil, and automation teams for interface alignmentParticipate in FAT, SAT, and commissioning support as neededLead technical discussions with clients, OEMs, and cross-functional teamsReport directly to the team leader and carry out any assigned tasks related to work. Strong communication skills in Vietnamese and English (English is essential)