Central Park Pumping Station

Greeley and Hansen performed preliminary and final design and provided construction services for the electrification of the Chicago Department of Water Management’s Central Park Pumping Station. This potable water pumping station, originally built in the 1890s and now serving approximately two million residents of the City of Chicago, was converted from steam turbine driven pumps to medium voltage electric motor driven pumps. The existing 60-mgd and 80-mgd pumps were refurbished to “like new” condition and new vacuum priming, lube oil, and hydraulic valve actuator power water systems were installed. Medium-voltage VFDs and a completely new electrical distribution system were designed and installed to control the new 2000 HP and 3250 HP, medium voltage induction motors driving the pumps.  

A new power distribution system was designed to replace the existing 240 V service, consisting of 12.47 kV main switchgear with two new utility feeders, 12.47 kV generator paralleling switchgear with four 2.5 MW, 12.47 kV generators, double-ended 12.47 kV-480V unit substation, and 480V power distribution. Various arc flash hazard mitigation strategies were incorporated into the electrical system, including differential relaying, zone selective interlocking, remote racking, and remote breaker operation, to provide a safe electrical work environment. New electrical equipment was installed in clean, conditioned electrical rooms with primary and secondary HVAC systems to maintain ambient temperature and humidity within acceptable limits to maximize the life of the new electrical equipment. A complete power monitoring system was incorporated into the pumping station SCADA (supervisory control and data acquisition) system.  

Multiple alternatives were developed for the most effective use of the existing site and building. Design alternatives and recommendations for all disciplines were presented and vetted in 16 collaborative workshops with engineering and operations staff during the conceptual and final design phases. Personnel safety was a key consideration in the evaluation of all alternatives. Our project team led the workshops and built consensus between all stakeholders to reach the best solution to each design challenge.  

Project Highlights: 

• The pumping station was converted from steam turbine driven pumps to medium voltage electric motor driven pumps. 

• Greeley and Hansen designed medium-voltage VFDs and a new electrical distribution system. 

• The team incorporated arc flash hazard mitigation strategies. 

• Phased construction maintained full pumping operation during conversion of pumps.