AWWA CSC91076

The Orlando Utilities Commission, Florida, operates ten water treatment plants which it monitors and controls through a SCADA system. The SCADA master is located at the Commission's control center near downtown Orlando. The most recently built water plant is the Sky Lake Plant. This paper discusses the Sky Lake control system, which was designed for remote operation of the plant. The major components of the control system are the remote terminal units communicating with the SCADA master over a leased telephone line and a programmable logic controller (PLC) installed to perform local control. Backup local manual control is provided for each SCADA and PLC control function. Automatic or manual well pump control may be selected by the operator through the SCADA system. Both modes control the pumps through the PLC. The system also has the capability to initiate automatic backwash of the activated carbon reactors through the SCADA system. A PLC controls the reactor valves and the backwash flow control valves. All switchgear breakers can be controlled through the SCADA system; the standby generator can also be remotely started and shut down. Chemical feed system equipment cannot be directly controlled through the SCADA system, but is interlocked to operate when the related pumping systems are running. Plant process variables are monitored through the SCADA system, including well pump discharge flow, individual reactor flows, and so forth.