Challenges

While some of the electrical infrastructure had been modified over the years, most of the existing equipment was original and required replacement or rehabilitation. And, with most conduits embedded in the concrete walls of the structure, tracing the existing panel circuits and wiring was difficult.

Existing systems had to be temporarily disconnected and/or relocated prior to installing new electrical distribution equipment and SCADA control systems. This required outages of the electrical gates and motorized valves that were used to control the flow of water over the dam spillway.

Process and electrical outage times were limited to short durations and weather had to be carefully monitored as heavy rainfall raised the reservoir to high levels. Adding to the challenge, the lower level of the dam was 70’ below the grade of the main building entrance and required access via the stairway.

Outcome

Throughout the course of construction, the facility continued to operate and maintain the required controlled flow of water to the City of Columbus Water Treatment Facilities.

Highlights

• Set two temporary 2500KVA transformers and refed the hospital’s existing 1960s double-ended switchgear lineup with 20 sets of 750Al. 10 to each side.
• Demoed out the four old AEP transformers and 4000amp bus duct from the existing underground electrical vault.
• Installed a new (G&W) primary transfer switch that will transfer upon loss of one of the two AEP circuits that feed the hospital.
• Installed a new double-ended substation with 3000KVA transformers.
• Installed six new bus ducts that had to tie into the existing bus ducts that feed the normal power to the hospital.