Department of Public Works
Accotink Pump Station and Freund House Pump Station Electrical switchgear Replacement
Contract No. CN14402001
Project No. WW-000001-004
Brendan Schillo, PE
(703) 659-7048 (office)
Cynergy performed a $2,572,533 contract for Fairfax County Dept. of Public Works for the replacement of 5KV service switchgear at two pumping stations. The engineer of record was Hazen and Sawyer; John Harmon, PE. The project was awarded in March 2015 and completed almost one year ahead of schedule. Major elements of work at both pumping stations included demolition of existing switchgear and associated electrical equipment, conduits and wire and furnishing and installing new Dominion Virginia Power approved 5KV service switchgear, associated electrical equipment, conduits and wire. The contract also included site work, underground duct-banks, paving, surfacing, fencing, grading, landscaping, erosion and sedimentation control, precast concrete, handrails and painting.
Principle features of the project at each pump station included:
- Underground 5KV concrete encased duct-banks and manholes
- Medium voltage 5KV cables and arc-proofing
- Medium voltage 4.16KV-480V 500KVA dry type transformer
- Utility 5KV CT cabinets with a medium voltage 5KV load interrupter switch
- Medium voltage indoor 5KV switchgear with vacuum breakers
- Control and information system installation including system testing
- Demolition of 5KV outdoor walk-in switchgear enclosures
Each facility had to remain operational 24/7 during construction. All service station outages had to be limited to 4 hours per occurrence, coordinated and approved by the owner. A detailed construction sequence was developed and had to be approved by the owner before any outage could begin. Each station had an existing diesel generator that operated during the outages. (The generators were installed by Cynergy under another contract)
Each station had an outdoor walk-in 5KV service switchgear that was being replaced with new 5KV vacuum switchgear located inside the building. New utility metering cabinets and a 5KV main service station switch was installed outside feeding the new 5KV switchgear inside the building thru new concrete encased duct-banks and manholes. The project was performed in phases to maintain the station operation. The Phase A included installation of the new indoor 5KV switchgear, utility 5KV CT/switch gear, concrete encased duct-bank/manhole system and 5KV cables ready for the first outage. The new 5KV feeder and service was installed and energized so the new switchgear and old switchgear were energized at the same time. 5KV station load feeders were then transferred from the old switchgear to the new switchgear one feeder at a time. Phases B and C were similar in operation required to maintain minimal outages to the stations at all times. Phase D, the final phase, was to make final configurations to the system and remove the existing station switchgear.
Miscellaneous installation items included; tree removal, new curb and gutters, paving removal/replacement, bollard installation around equipment, grounding systems, drip pan and framing supports for existing mechanical piping, relocated metal stairs and handrail installation, control circuits, and concrete housekeeping pads, etc. Commissioning, operational demonstration of all systems and field testing were a large component in the project. Third party testing was provided for all medium voltage equipment, ground systems and cables. Factory field services were provided for the switchgear. Hands on training and operation and maintenance manuals were provided for all operational systems.
Other items provided by Cynergy were an arc flash & coordination study, test pits, utility locating, temporary fencing, erosion and sediment control, site clearing and site restoration. Providing project photographs, construction scheduling, quality control, safety and security were important elements of the entire project.