Open and fully distributed architecture for an energy management system

This paper describes the energy management system (EMS) being implemented for Seattle City Light. The project was contracted in January, 1992 and is scheduled for commissioning in 1995. The system will manage the 240 and 120 kV transmission network as well as the generating plants consisting of eleven hydro plants and a share of a thermal power plant. The totally open system architecture is presented. It is based on a fully distributed and redundant configuration of SPARC servers and full-graphic workstations running under UNIX with no critical function single point of failure. Data links will interface the EMS with several intra/inter-utility information systems, the backup control center, a PC network and a weather information system. Interfacing with a future AM/FM system and a future distribution management system is also envisaged. The structure of the software system is described and the distribution of the database and the application functions among the system components is explained. The advanced applications are presented. They consist of a complete interchange scheduling and energy accounting capability with a modern spreadsheet interface, automatic generation control (AGC), generation dispatch, reserve monitoring, post mortem analysis, short term load forecast, a complete package of online network analysis programs and a dispatcher training simulator. The hydro optimization capability with reservoir modelling is highlighted.<
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