Central Plant Generators
City of Virginia Beach, VA
PACE Collaborative is completing the design to provide standby emergency generators for the Central Plant for the City of Virginia Beach. The project will include the diesel engine generators standby rated at 2,750 kW at 0.8 pf, 3,437 kVA, 4,160 volts, 3-phase to deliver 2,750 kW at 4,160 volts. The generators will be arranged for N+1 redundancy, where one generator will back up the other generator if one were to fail to start upon loss of power from Dominion Energy.
The Central Plant provides hot water and chilled water to most of the buildings at the Municipal Center, many of which are critical to City operations. It includes three chillers operating at 4,160 volts and one chiller operating at 480 volts, 3-phase. It also includes multiple dual fuel fired boilers that operate off of natural gas or fuel oil.
The Central Plant presently only has one diesel engine generator, standby rated at 80 kW, 0.8 pf, 100 kVA at 480 volts, 3-phase. If the Central Plant were to lose power from Dominion Energy, this generator only has the capacity to operate the Central Plant emergency lighting, computers for DDC, and a limited number of hot water pumps. Consequently, it would not be able to provide hot and chilled water to the other buildings at the Municipal Center. This includes critical facilities such as the fire station, emergency call center, the correctional center, Building #2 (Data Center), and other facilities.
The standby generators being provided under this project will be located in a new building located south of the Central Plant, and west of the ice field that serves the Central Plant. The building will be masonry with a brick veneer and will be designed to match the exterior appearance of the Central Plant building. It will include a mansard roof with slate shingles, brick, and windows to match the Central Plant, and sound attenuating exhaust louvers for each generator with intake hoods located on the roof. The building design was reviewed by the Historic Review Board and the Architectural Review Board, and has received approval.
The generator will operate through a 5 kV switchgear with vacuum breakers. The transfer scheme will be through the transfer switch control system, which will control the 5 kV vacuum breakers.
The project included a study to evaluate the utilization voltage at 480 volts, 3-phase vs. 4,160 volts and emissions for Tier 2 or 3 vs. Tier 4. As a result of the study, the City elected to go with the 4,160 volts and Tier 2 or 3.
The project also included an evaluation of multiple site locations. The final location selection required the removal of the existing 20,000 gallon underground fuel storage tank and the provision of a new aboveground, double wall, 20,000 gallon fuel storage tank. The fuel storage tank provides fuel for the generator and for the boilers in the Central Plant when they are not operating on natural gas. Due to the size and appearance of the tanks, a masonry and brick wall was provided to conceal the tank from the public.