This class presents a real-life case study of a successful power substation design project using Autodesk Revit MEP software. It not only covers normal mechanical, lighting, power, security, hydraulic, and fire protection design, modeling, and documentation, but also introduces innovative ways of designing high-voltage cables in tight 3D building and tunnel spaces to meet the strict bending radius requirements. The solution provided some unprecedented methodology for high-voltage substation designers to resolve coordinated multidisciplinary 3D design issues. The methodology readily takes into account bending radius, electrical clearance, cable joints, site work, high-voltage cable position alternating and penetration in tunnels, high-voltage cable connections to Gas-Insulated Switchgear (GIS) and transformers through conduits and cable trays, lighting, and ventilation design.