System Stem Ideas Vijay Vittal

Idea from Hydro Quebec Hydro-Quebec uses transfer limits as a security indicator in daily operations. These limits are calculated off-line and monitored in real-time.  The limit calculations are based on time domain stability simulations for a given list of contingencies. Transient, fast voltage collapse stability and non-linear control devices (SVC, switched shunts, synchronous condenser and SPS) are considered. The status of key network elements (ex. line, shunt, series capacitor and power injection ...) affects the severity of each contingency and consequently has an impact on the transfer limits. The impact and sensitivity of each element is presently found based on experience using a trial-and-error process requiring a large number of stability simulations.   Are there more efficient ways to find the sensitivity of the network elements’ impact on the severity of system response and ultimately the transfer limits bypassing usual time-consuming stability simulations when requesting a sensitivity study? The final results of the study will be a list of ordered impact elements and the scale of the impacts. Considerations include sensitivity of severity (local and global) and severity impact on local limits.

Determination of Varying Operating Conditions and Critical Contingencies In two recent PSERC projects associated with S-27 PMU measurements and Decision Trees have been successfully applied to determine critical attributes and their thresholds The accuracy of the Decision Trees depends on getting a wide range of operating conditions which have a good mix of stable and unstable cases.

Determination of Varying Operating Conditions and Critical Contingencies Systematic methods need to be taken to choose operating points that will provide a wide coverage of the operating points. Systematic methods to choose contingencies that will give a good mix of stable and unstable cases that would provide excellent training for the decision trees.