Transient Security Assessment in Real-time at Southern Company

Southern Company Services (USA) has successfully implemented a continual transient security assessment (TSA) process utilizing Powertech's TSAT software at their system control center. Southern's EMS provides an updated powerflow case from the real-time state estimator to the TSAT application through Powertech's DSA Manager on an hourly (24times7) basis. One unique aspect of the enhanced state estimator model is a highly reduced external system model, which provides a virtually identical dynamic response as the much larger original from which it was derived. Southern has already benefited from this on-line TSA system during the post-Katrina system restoration. Further work is ongoing to enhance the selection of contingencies evaluated, and to integrate summary results of the stability studies into Southern's EMS alarms processing subsystem