An energized effort

Contractor battles time to upgrade Geismar substation

By Sam Barnes

In less time than it usually takes to set up a jobsite trailer, a design-build contractor started and completed an electrical substation upgrade in Geismar.

Industrial Electrical Services of Baton Rouge and its subcontractors recently relocated an existing shunt capacitor bank, demolished foundations, built new foundations and installed a new capacitor bank, electrical bus structure, tuning reactors and protective relaying panel in just 10 days.

The project ultimately improved the plant's "power factor" and reduced electricity costs for Vulcan Chemical. The plant owner mandated the extreme fast pace so the work could be performed during a scheduled turnaround.

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"We were originally selected as a consultant to develop possible solutions for Vulcan's future power needs," said Tim Ballard, power systems consultant with IES. Vulcan then selected the conceptual solution that best solved their power requirements.

"By the time we had provided a detailed estimate of the conceptual design and construction specifications our intimate knowledge of the project and previous experience with Vulcan made us the obvious choice for seeing the project to completion."

Most critical during the planning stage was finding a way to squeeze new harmonic filter components into an existing, energized substation that provided only minimal extra space.

"Essentially, the existing capacitor bank had to be disassembled and moved over to make room for the new one," said David Sterken, IES electrical systems consultant.

Vulcan's prerequisite was that the relocated capacitor bank be back on line at the end of the outage. If needed, IES could take more time to install the new capacitor.

"But we decided, from a cost and time standpoint, that it would be best to install everything during this one outage," Sterken said. "Remaining outages would last less than a day and would have required quick mobilizations with very little notice.

"Everything was finished and ready for start-up at the end of 10 days."

To do so much with so little time, all of the components in the facility had to be fabricated and placed into two separate staging areas prior to groundbreaking, one inside and one outside the fenced, high-voltage substation. The staging areas were close enough to the site to allow a single crane to lift and set the largest components from one location.

"We provided a major portion of the design up front rapidly in order to get all the specifications and details together to give the many suppliers enough time to go through their manufacturing process," Ballard said. Major equipment arrived on site well before the scheduled outage to facilitate inspection, testing and staging.

IES subcontracted the construction to a team made up of Harmony Corp. of Baton Rouge, Auger Services Inc. of Prairieville, Feliciana Fabricators LLC of Clinton and Scafco LLC of Baton Rouge. Stephens Engineering of Baton Rouge was the civil engineering consultant.

Harmony began the operation by attaching specially fabricated steel braces to the sides of the existing 12,000-lb. capacitor bank, then lifting and placing the bank onto a flatbed trailer for hauling off-site. The capacitor structure was secured to steel beams and left on the trailer until the new foundations were complete.

"The braces helped distribute the weight and kept us from having to put undue stress on certain areas of the capacitor bank," said Harmony project manager Larry Robbins.

Getting the existing capacitors out of the way quickly enabled Auger Services to demolish existing concrete slab foundations and drill 20 shafts as foundation for the new substation components. The 18- to 24-in.-diameter shafts measure 20 ft. deep.

"There was a big concern during the demolition that we would find unexpected obstructions beneath the slab, such as old pilings or drilled shafts," Sterken said.

Fortunately, an unmapped duct bank was the only significant obstacle.

"We had to re-design an equipment foundation so that it straddled the duct bank," he added. "It's not uncommon for duct banks to be somewhere that they're not supposed to be. There are decisions made in the field during construction to move them or make them larger or smaller. These alterations in design aren't usually transferred to the plans."

To help speed foundation construction, Auger Services used a 4,000-psi high-early yield "hyper mix" so that design strengths could be achieved in 24 hours, allowing Harmony to begin placing equipment the next day.

Ed Spille, Auger Services operations manager, said special additives in the Dolese Concrete-supplied ready-mix made it "hot to the touch."

"The hyper mix had to be tremied into the shafts because of the limited size of the work area," Spille added. "A pump truck wouldn't fit in there." Auger Services shuttled the concrete with a concrete bucket lifted by a 40-ton Mantis crane.

To ensure design strength was achieved, the crew used a patented testing process supplied by intelliRock Systems of Stillwater, Okla. The method, called Concrete Maturity, provided a real-time reading of the compressive strength of the concrete.

"We used a hand-held monitor that plugged into a sensor inserted in the concrete," Spille said. "The test provided information on the rate of hydration, measured in degrees Celsius per hour." The concrete actually out-performed its design specifications by reaching 5,600 psi.

As foundations were completed, Harmony moved quickly behind the Auger crew to place new substation components.

"We first lifted a pre-assembled, 11,000-lb. bus structure using an 120-ton crane," Harmony's Robbins said. "We backed Auger out of the way, set the bus structure and then began making connections." The bus structure was lifted 60 ft. high, transported about 75 ft. and brought down in place.

The crew made 16 additional lifts in the two hours that followed.

"After we set the main bus structure, we grabbed and placed smaller components to complete the structure," Robbins added.

Moving north to south, Harmony followed the Auger crew by installing new reactors, the existing capacitor bank and a new capacitor bank onto the new foundations.

Sterken said the scaffolding operation was another critical component of the project because Scafco had to erect scaffolding quickly so Harmony could make final connections.

"They had to work fast while being careful around some extremely delicate porcelain equipment," he added.

About 35 people had to work around-the-clock in the tightly compacted jobsite, which made safety a primary concern.

"We posted a one-line diagram inside the substation that had the energized equipment and substation structures highlighted red and the de-energized equipment and substation structures highlighted green," said Sterken. Site safety meetings were conducted for each crew and the diagram was updated and reviewed each time the energized and de-energized equipment changed.

"We also used flagging tape to mark each piece of equipment or structure as de-energized or energized."

Ballard said the project was a battle against time.

"Any delays would have become cumulative, delaying the plant startup," he added. "Teamwork and the skills of the contractors were key elements to the project's success."