Distributed intelligence in supervisory control and data acquisition systems

Prospect Electricity, Australia, is installing a new SCADA system which is planned for development as the heart of future distribution automation. A unique feature of this SCADA system is the use of an intelligent microprocessor based remote substation terminal unit (STU). In addition to its SCADA functions the STU performs complex local functions automatically within the substation and provides an interface for local operator control and information display. The author traces the development and introduction of the STUs and describes the technical aspects of the hardware components. A project of considerable interest is the further development of the STU to employ distributed intelligence within the substation by way of the latest local area network (LAN) technology. The LAN concept is discussed and it is shown how it will extend beyond the bounds of the zone substation to include the adjacent distribution system