An expert system for comprehensive on-line economic-security controls of distribution systems

Abstract

This paper presents an architecture which assists the system operator to perform comprehensive controls in a distribution SCADA environment. A typical zone substation and open-ended multiple outgoing feeder group is used as an example for testing the validity of the approach. The paper first reviews a prototype expert system which was developed by the authors to help operators provide sufficient security margins against overloading by meeting certain heuristic operating guidelines. Next, the paper describes new functions of the expert system aiming for comprehensive controls of each zone substation: (1) generalized operating guidelines for meeting security constraints for all loads; (2) additional procedures for removing any existing busbar/feeder overload, restoring customer loads after each feeder fault and/or repair, reconfiguring busbar connections after each supply transformer outage, and reducing distribution losses on one feeder group at a time; (3) tracking substation load variations for continuous security monitoring and assessment of substation security; (4) additional numerical modules for minimizing overall distribution losses, and knowledge-based assessment of overvoltages due to inter-zone substation switching.