PROJECT
PROFILES

Star Enterprise Division "A" Electrical Substations

This project won the 1994 ABC Pelican Chapter Excellence Award.

Star Enterprise's Refinery in Convent, Louisiana manufactures various grades of unleaded gasoline, diesel, avjet, kerosene, and fuel oil. In a recent electrical upgrade, Star Enterprise replaced the electrical substations for Division "A". ISC was awarded lump-sum contracts for the entire construction portion of the project, both the pre-turnaround and the turnaround phases.

The scope of the division "A" electrical substations project was to construct and provide electrical power for two new 480-volt substations, one new 2400-volt substation, and transfer all division "A" electrical loads to these new substations. This scope was accomplished by installing underground ductbanks with 500 CMC 15KV feeders from the existing main substation number four to the three new substations, installing new substation foundations, setting equipment, installing downstream 480-volt ductbanks to existing motor control centers and pull points, and transferring electrical power from the old substations to the three new substations.

The 15KV ductbank from the main substation to the three new substations consisted of installing four new 500 MCM 15KV feeders in six-inch conduit encased in a red concrete and rebar envelope three feet wide averaging five feet deep and running 2400 feet in length. This ductbank crossed under a railroad spur, crossed two major roads, and was installed in the centerline of a roadside ditch for 70 percent of the distance.

Six above-ground structural concrete pull points, each 9 feet by 18, were constructed in place and strategically located along the ductbank. Steel covers, each four feet tall, were installed on the pull points after the cable was installed. Approximately nine miles of single-conductor 500 MCM 15KV cable was pulled through six concrete-encased, six-inch conduits and pull points without any splices between the main substation and the three new substations. 15KV terminations and cable testing were performed. Also, fiber optic communication cables between the main substation and the three new substations were installed, terminated, and tested.

Substation and transformer installations involved constructing structural concrete foundations with drill shafts. Three pre-fabricated, metal-clad substations weighing from 42,000 lbs. to 62,000 lbs., six transformers weighing from 11,000 lbs. to 35,000 lbs., and six 15KV switches were set on the foundations as they arrived at the plant site. Electrical connections were installed between the substations and transformers. Grounding was also installed for the substation and transformer foundations.

The downstream portion of the project consisted of installing 480V and 2400V feeders from the three new substations to the existing motor control centers and pull points in three different operating units. This was accomplished by installing underground ductbanks and overhead conduit banks with 25,000 feet of five-inch, four-inch and three-inch galvanized steel conduit and 9.5 miles of 350 MCM 600V and 500 MCM 4KV cables.

The underground ductbanks were installed down unit alleys and turned into the unit areas at various motor control centers and pull points. Numerous pull-point and conduit stub-ups were constructed. Three major road crossings were required that entailed concrete pavement removal and replacement in all three units.

Many underground foundations and obstructions were encountered. At the existing motor control centers, new structural steel racks with foundations were installed and equipped with new main breakers. Cable terminations were made at the three new substations and at the new motor control center main breakers. Conduit and cable runs from the new main breaker racks to the existing motor control centers and from the new substation to various pull points were installed so as to minimize electrical outages.

After the installation of 15KV feeders and substations were completed, the three new substations were energized and tested. During the division "A" turnaround, 25 motor control centers were disconnected from the old substations and re-fed from the three new substations. The cutovers were performed by connecting the new feeders at existing pull points or at existing motor control centers. This completed the downstream portion of the project.

ISC performed all of the work on the project, including electrical, fiber optic, civil construction, ductbank installation, setting equipment, and electrical cutovers. Coordination of subcontractors was required to install steel casings under the railroad spur, for cable testing, structural steel access platforms, concrete saw cutting, and asphalt repairs. Star Enterprise furnished all of the electrical commodities for the project. Extensive coordination was necessary with the material supplier's agent to ensure timely delivery of materials.

The division "A" electrical substations project required over 25,000 man-hours and cost $1,085,000 for electrical contracting services alone. ISC performed the work in a rainy four- month span, from December 1993 through March 1994, with a peak manpower level of 60 associates. ISC successfully completed this project in three different operating units with a perfect safety record and on schedule.