Integration of substation protection, control and data acquisition systems

The control section in an electric utility substation serves to provide local dynamic display of the station one line, switching of station equipment (circuit breakers, disconnect switches), metering functions, and annunciation of alarms. It also provides facilities for the operator in the control centers to oversee, supervise and control the station. In the past few years, a variety of microprocessor-based digital devices with communication capabilities, have been introduced into substations. These digital devices include protective relays, fault recorders, and metering units. It has become apparent that in order to make full use of this new technology, a means of collecting and organizing the data is required locally in the substation. Such a system is available today using proven data acquisition and control technology. This paper describes the utilization of industrial local area networks (LAN), human machine interfaces (HMI), and programmable logic controllers (PLC) in a power utility in the Pacific Northwest of the USA. This configuration provides the basis for building a wide range of real-time supervisory monitoring and logging, control, and information management systems, including the integration of data from protective relays and other intelligent electronic devices (IEDs).