Analysis of frequency extrema in the Eastern and Western Interconnections, 2010–2011

Previous research into the occurrence of power system frequency extrema revealed that common patterns emerge over time. Using an existing algorithm developed for detecting and validating the extrema, we examine their occurrence in the Eastern (EI) and Western (WECC) Interconnections from January 2010 through September 2011. The results indicate that the frequency extrema continue to follow certain hourly patterns, regardless of the interconnection or year. Average weekly extrema values did not appear to have any discernible trend, while average monthly values exhibited some rough similarities from year to year. Analysis also revealed that yearly extrema averages for both the EI and WECC were almost identical for the past two years. Such information might be useful for developing operational guidelines for grid dispatchers.