- Refinery 35-kV Refeed Project
A refinery primary utility power supply was changed from bare 35-kV overhead lines to a new 138-kV outdoor substation with 35-kV GIS switchgear. The goal of this project was to refeed 16 existing unit substations and four new unit substations with 35-kV insulated CLX power circuits. The majority of the substations are double-ended, requiring circuits to have independent routes for maximum reliability. The routes include a combination of cable tray in existing piperacks, new structural supports, underground crossings and overhead messenger wires in galvanized steel poles.
The overhead messenger route was designed for six 35-kV, 500-kcmil CLX cables, each lashed to a messenger, and six 24-fiber cables for relaying and power monitoring. The route was approximately 2,600 feet, utilizing 16 galvanized steel poles. The longest span in the route was 240 feet, accommodate field underground and above-ground obstructions. The foundations were 6-foot-diameter drilled shafts.
- Construction support
The refinery owner requested our electrical and civil/structural design services to refeed electrical unit substations from their new 138-kV/35-kV substation. Given the complexity and scale of the project, we used Plant Design System software to coordinate the design and interface points between our team and four other engineering firms responsible for design of portions of the refeed project.
For the overhead messenger route, our team was responsible for development of the route, identifying optimal structure locations, hydro-excavation specifications, steel pole design criteria drawings, steel pole specifications, pole vendor drawing reviews, foundation design, pole erection and assembly drawings, grounding drawings, stringing specifications, and cable tray design to transition to power control rooms for power cable terminations.
- Refinery environment
- Messenger supported insulated aerial cable
- Vacuum excavation required for foundations
- Cable tray and substation termination
- Use of Plant Design System software for coordination between disciplines