SUNY Cortland Campus Wide Electrical Distribution Upgrade
C&S designed a campus-wide upgrade of the site electrical distribution system at SUNY Cortland. The existing system was aging, of questionable reliability, and had limited expansion capabilities. It consisted of a 115 KV substation with two 10 MVA transformer banks, one feeding 13.8 distribution on part of the campus, the other feeding 34.5 KV via overhead distribution to another substation on the north part of campus. The north substation transforms the power down to 4,800 volts and feeds the north part of the campus.
Phase 1 replaced the 115 KV substation with two 10 MVA transformers having a 13.8 KV secondary, providing a new distribution building housing 15 KV switchgear and capacitors, allowing upgrade of the entire campus to 13.8 KV. The 15 KV gear was configured as a double-ended main-tie-main, so with the loss of a single transformer the campus will remain in full operation. This allowed the 35.4 overhead distribution to be removed and will eliminate the north substation at the completion of Phase 3.
Phase 2 included 22,500 linear feet of ductbanks and manholes configured into a three-loop distribution system feeding 13.8 KV to 28 buildings. Each building has a SF6 type loop switch that allows a single building to be taken off line while maintaining service to the other buildings on the loop. Loop 3 was commissioned, under Phase 2, serving approximately 1/3 of the campus.
Phase 3 will complete in fall 2017 and includes the completion of loops 1 and 2, removal of the overhead 34.5 kV line and site modifications to the substation.
The new distribution configuration will have greater reliability and continuity of service. Fault indicators at each loop switch will indicate a fault in a cable segment, so it can be quickly isolated and repaired. Each cable segment consists of 133 percent insulated EPR copper cable in five-inch PVC conduits built into a reinforced concrete ductbank. Additionally, cable segments are typically splice free to further increase reliability. Metering is provided at the substation and each individual building, which is tied into the campus’s building management system, to allow for full monitoring of the electrical usage on campus. There will also be two four-inch conduits with separate pull boxes along with the power ductbanks for installation of a new fiber optics duct bank throughout the campus.