Extending traditional planning methods to evaluate the potential for cascading failures in electric power grids

A method of extending traditional planning methods and tools to evaluate the potential for cascading failures in electric power grids will be presented. By expanding on traditional transmission planning and reliability analysis methods, a study technique that produces reasonable and verifiable assessments of electric grid vulnerability to widespread blackout is possible. The methodology also provides an objective measure of the NERC reliability criteria allowing ldquoplanned/controlledrdquo loss of load for Category C ldquodoublerdquo contingencies. This is accomplished by identifying contingencies that will not result in ldquothe uncontrolled successive loss of system elements...which cannot be restrained from sequentially spreading beyondrdquo a predetermined area even though they cause overloads and voltage violations (Applicable Rating - A/R violations). Two innovations that allow an analytical solution for all Category C contingencies and automatic solutions for grids operating in extremis will be presented. Detailed results for an example analysis of the Eastern Interconnection will be presented along with statistical results from an actual study. Potential improvements and extensions to the analytical process will be suggested.