Rutgers University College Avenue campus substation expansion

University facilities personnel can monitor substation conditions from remote locations.

07/20/2017


Daily power loads at College Avenue substation at Rutgers. Courtesy: RMF Engineering

In 2013, Rutgers University Facilities & Capital Planning was preparing for a rapid campus expansion. The university had plans to build an Honors College and a new Academic Building on the College Avenue campus, meaning the electrical demand of the entire campus was about to greatly increase. The substation serving the College Avenue Campus was approaching its capacity, and the school needed to come up with a timely solution to expand the substation and the school's electrical capacities while remaining operational.

To meet the electrical needs of the campus, Rutgers chose RMF Engineering to design the substation expansion. Upon completion, RMF built a new substation adjacent to the existing substation; energized the new substation; transferred campus energy load and removed the old substation gear.

Design challenges

There were several obstacles that could potentially hinder the successful completion of the project. First, timing was tight. While a project of this size could be expected to take 18-24 months to complete, this project needed to be complete in less than 14 months. Second, the expansion site is surrounded on three sides by busy streets, leaving only a narrow sliver of land with a steep embankment running right through it to be worked on. Additionally, the campus needed the substation to remain fully operational throughout the construction period, keeping the lights on for the university's students.

Solutions

To fit within the narrow project space, RMF selected a sheltered-aisle type of house manufactured by Powercon Corporation for the 4.16 kV switchgear, along with two 26/4.16 kV transformers, and a pair of 26 kV circuit breakers to be placed in a single file arrangement on the site to stay within the property boundaries. To work alongside the steep embankment, RMF designed a retaining wall three feet high at one end and over 10 feet high at the other, abutting the property line. The retaining wall created an essential level area just large enough to accommodate the equipment.

Rutgers and RMF chose to enclose the site with an aesthetic yet functional fencing design. Part of the fence was set at ground level, while the other part was mounted atop the retaining wall, affording excellent security all around. The 'anti-scale' fence specification places the pales 1 ½" apart, too close for a foot to slip between, making it difficult to climb. Because of the narrowness of the site, clearance between the fence and the compartment doors on the switchgear house was marginal at best. To address the minimal clearance area, a rolling gate was installed to open the full length of the switchgear cubicles, resulting in easy access and open space around all of the cable entry compartments.

The transformers, supplied by Virginia Transformer Corp., are rated 8/12 MVA, KNAN/KNAF. Although the oil is Envirotemp™ FR3™, derived from renewable vegetable oils and relatively harmless to the environment, containment was installed to prevent an accidental release that could flow to the nearby Raritan River. The containment system included oil filtration panels that allow normal rainwater and snowmelt to pass through, but stops the passage of oils.

Keeping in mind that reliable electric power is critical in an institution the size and scope of Rutgers, RMF designed the substation expansion with backup measures. The two source feeders from Public Service Electric and Gas have flopover controls so that if the primary source loses power, the motorized switches automatically transfer to the backup source. The two transformers provide redundant capacity for existing and anticipated campus load.

On the 4.16 kV side, the bus is split with a tiebreaker, arranged so that the full campus load can be served from either bus half, and feeder pairs are supplied to all downstream loads. Battery backup is provided for control and protection functions with redundant battery chargers. Control power transformers, 4160/480 volt, one connected to each bus half, feed the two source sides of an automatic transfer switch so that either bus half can be de-energized for maintenance without losing control power. A cam-lock connection point is provided at the 480-volt level to enable quick connection of a standby generator if needed.

To maintain arc flash safety for operators, breaker controls were wired to a 'mimic panel' located at one end of the switchgear house, as opposed to the front of the breaker cubicles. This arrangement enables the operator to execute open and close commands without having to stand right in front of the gear. A SCADA system by Schweitzer Engineering Labs was installed near the mimic panel, enabling university facilities personnel to monitor substation conditions from remote locations.

Honors College expansion

The new Honors College, located on George Street directly across from the substation, was constructed concurrent with the substation expansion. George Street is a very busy thoroughfare, making open trenching for the ductbank impractical. Instead, a micro-tunneling, or 'jack and bore' method was used, enabling the work to be done without disrupting traffic. Though only four conduits were required to power the Honors College, the bore contains a 16-way ductbank, providing much spare capacity at the road crossing.

The existing equipment at the site included a disabled transformer that was in the way of new ductbanks and needed to be moved. It was located dangerously close to exposed overhead buswork energized at 26 kV; safe removal of the transformer required that a portion of the overhead bus be de-energized. That in turn meant that two of the remaining three transformers needed to be de-energized as well, leaving a single 50-year-old transformer with nameplate capacity of 2000 kva to serve the entire campus.

On a mild September night, in the still pre-dawn hours, Rutgers' facilities personnel shut down non-essential loads at the central utility plant long enough to crane the transformer safely off its pad and onto a flatbed trailer. Six months later, the first of two new 8/12 MVA transformers was energized, replacing all three of the 50-year-old units. During this phase of the project, Rutgers' utilities personnel helped develop the switching and feeder-phasing procedures required to transfer loads to the new substation without outages to the campus.

With the project completed, Rutgers now has the electrical capacity and reliability to keep the College Avenue campus bustling with students for years to come.



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