Roseland Pumping Station Conversion, Chicago

In 1911 the city of Chicago built the steam-powered Roseland Pumping Station. With a capacity of 300 million gallons per day, the RPS is the only source of drinking water for 750,000 people on the city's South Side and in the southern suburbs.

During the unusually high peak demands in the summer of 1995, the reliability and operational difficulties of the aging steam systems become evident. The Chicago Department of Water Management initiated a fast-track program to upgrade the RPS pump drives from steam turbines to electric motors.

Contract documents for the incoming electrical system and standby electrical power required to operate the new electric motors were prepared.

Work included a new electrical building to house the electrical medium voltage switch gear, variable frequency drive systems, diesel- and natural-gas-fueled standby generators and generators load banks. Rehabilitation affected the existing centrifugal water pumps, expansion and modifications to the supervisory control and data acquisition system and modifications to the existing pump building.

An underground piping and access tunnel was provided between the new electrical building and the existing pump building.

The design of a water pumping station of the size for Chicago usually requires 36 to 48 months. Working closely with Department of Water Management staff, the design period was streamlined to less than 18 months through regular workshop meetings and onsite evaluations.

First for Upgrade

The RPS was selected as the first of five steam-driven pump stations to be upgraded because it, unlike the others, is isolated geographically and is not augmented by a nearby facility.

It was necessary to restrict the number of pumps that could be taken out of service at one time for conversion to maintain the full operation of the pump station at all times.
The length of time a pump would be out of service was also minimized.

Associated electrical equipment was pre-installed in the new electrical building so that only the new electric motors and pump rehabilitation were required to be installed during each pump's conversion. The project was phased over 3 1/2 years to facilitate a smooth transition to electric power without interruption of service.

With the increasing number of electrical power outages in the area, the electrical system was designed with eight 2,000 KW standby generators - five diesel fueled and three natural gas fueled ¾ and parallel equipment.

The diesel-fueled standby generator system allows the RPS to continue full operation through brownouts or complete power outages. When economically feasible, the natural gas standby generators can be installed to allow the RPS to reduce electrical costs by paralleling with the local utility for peak shaving.

Two Water Systems

The RPS serves two separated water distribution systems.

The low-pressure zone supplies water at a nominal pressure to the low elevation areas of the south and southeast sides of the city and adjacent suburbs. The high-pressure zone supplies the high elevation areas of the city and suburbs to the west of the station.

To meet the widely varying demands of the water distribution system, separate variable frequency drives were provided for each pump. The operating system still allows any pump or combination of pumps to be connected to either distribution system to maintain a relatively constant water pressure in each system, thereby reducing the hydraulic shock to the aging water mains. VFDs also provide power savings.

The conversion from steam to electric pumps will save the city on estimated $2 million annually by reducing operating and maintenance costs, in addition to increasing flexibility and reliability of operation. The majority of the cost savings is due to the low maintenance required for the electrical components vs. the aging steam equipment.
The jury said, "This was a huge undertaking. To take what was there and update it was a tremendous feat. This site is packed with equipment."

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