ing environment.This meant that client/server architecture was the models developed needed to The major accomplishment designed for the system.It inte emulate the operation of the dis- grates the advanced power sys- tribution feeders and compo- of the project lies in tem applications that run on nents in great detail and with exploiting the integrated UNIX workstations with a Win- great accuracy and the solution environment for improved dows-based graphical user inter- algorithms needed to be robust face (GUD running on PCs. and numerically efficient. computing and processing The PC/Windows-based GUI The innovations of the project, was specifically developed with however,go beyond building extensive involvement of PG&E's advanced analytical tools.The distribution operators and engi- major accomplishments are in the exploitation of the neers.This interface uses the computer-aided-design integrated environment for computing and processing.A (CAD)technology and the California grid coordinates (CGC)to offer users geographical views of PG&E's distri- bution systems encompassing topological information, line equipment data and analysis results.Street maps have also been integrated as background to enhance the Raw SCADA dntn trom various source usability of the information. Figure 2 illustrates the overall architecture of the sys- INFORMATION tem.All components of this system along with their interactions with one another are depicted in this figure. Intormation on 'system operations ineludi ·Fault Location- The main components of the system are data sources, Potertial loading or voltage problems advanced applications,and the graphical user interface. Impact of dispersed generation The components of the system have been developed Analysis Function using different,yet standard,programming languages and reside on different hardware platforms.This is par- DECISION ticularly true for the existing data sources that had been developed over the last 10 years.Hence.it was of para- Recommendation for secure and optimum operat Switching operations to isolate fauits and restore mount importance for us to adhere to industry standard .Switchind operalions to relave overload practices and tools in designing the interfaces among Canreg control to improve voltage profile and VAB these components. Mitigate the impact-of distributed resources' Control/Recommendation Functions Data Sources The source of the real-time data is mainly PG&E's exist- Figure 1.Overall objective for the RADIAS project ing distribution SCADA systems.The system extracts this data from the real-time database of the SCADA mas- ter station computers.For PG&E,the distribution SCADA Facility Database master station is mainly a PC/Windows-based system Fault SCADA Senso called WinSCADA.Real-time data is transferred to the system applications periodically through standard DATA TCP/IP communication. Fault-related data is passed by fault sensors that State (load) Saved detect and measure fault currents.If there is a fault on a Estimation distribution feeder,all the installed fault sensors along. the fault current path will report applications,their loca- tion IDs,and the fault current magnitudes they have measured. Faull Short Power Location Distribution system models and parameters as well as historical information are acquired from a distributed INFORMATION relational database named D-EDSA database.Each one of PG&E's operating divisions keeps the information on its -Volt/VAR distribution feeders in the D-EDSA database on the divi- Reconfiguration -Control: sion's UNIX workstations.Information on system models DECISION and parameters include feeder topologies,equipment locations,and data and line section parameters.Histori- Figure 2.RADIAS architecture cal information is mainly limited to line section load types 32 IEEE Computer Applications in Power