Analysis of frequency extrema in the eastern and western interconnections

The power system frequency is an important indicator of the grid´s health and stability. With the advent of wide-area phasor measurement systems, it is now possible to analyze the historical frequency characteristics of different synchronous interconnections. Using several years´ worth of frequency measurements obtained from FNET, we examine the occurrence of frequency extrema in the Eastern and Western Interconnections with respect to time. We present an algorithm used to detect the extrema within the recorded frequency data, and discuss some of the challenges associated with doing this type of analysis. The results indicate that frequency extrema tend to follow certain hourly patterns, regardless of the interconnection or year. Some common variation in extrema magnitude is observed from month-to-month across several years. The study will help us to understand the grid´s performance and detect trends over time. Such information might be useful for developing operational guidelines for grid dispatchers.