Integrated CHP SCADA System for Hospital Expansion

The Johns Hopkins Hospital, the teaching hospital and research facility of Johns Hopkins University School of Medicine was planning a major expansion at their East Baltimore campus. The new 1.6 million-square-foot building, one of the largest hospital construction projects in U.S. history, was to span five acres and include two 12-story patient towers, the most sophisticated diagnostic imaging equipment, and the latest technology for minimally invasive procedures.
The Challenge

A critical requirement for the new facility was a combined heat and power system to provide a reliable source of back-up power. A significant expansion of existing North and South Power Plants was required to support the new facility, as well as other general needs. New generation and other ancillary equipment were to be installed in each plant, including:

  • 2, 7.5 MW Combustion Turbines
  • 2 Heat Recovery Steam Generator (HRSG)
  • 40,000 pph Firetube Boiler
  • Natural Gas Compressors and Blowers
  • New and Existing Paralleling Switchgear
  • HVAC Systems within the power plants

Most of the new equipment packages were to be provided with Rockwell PLCs and local operator interfaces only. An integrated SCADA system was required to provide a central operator interface, alarm annunciation, data collection and reporting for the new systems as well as several existing systems such as an energy monitoring system, boiler system, and steam metering system.
The Solution

ACC implemented and installed a central SCADA system for each plant. Each system communicates with the local Balance-of-Plant PLC as well as the equipment systems for its plant. The result is an integrated SCADA application with a common look-and-feel across the entire system, facilitating the control and monitoring from a central control room.

The majority of the new equipment systems were provided with Rockwell PLCs, and Ethernet IP was used for SCADA communications. The interfaces to existing equipment varied, consisting of Modbus/TCP, Modbus RTU, and Bacnet.