Localization of Forced Oscillation - A Model Based Approach

Abstract

The electricity grid is one of the most impressive engineering feats of the modern era. It enables power transmission from a variety of generation facilities to end users over long distances. It provides electricity to buildings, industrial facilities, schools, hospitals and homes, and it does so every minute of every day, year-round. At the same time, it is a complex system that is vulnerable to stability issues that can lead to system failure and blackouts. This thesis focuses on a particular stability concern: Forced Oscillations. The detection and mitigation of low-frequency forced oscillations are important for reliablegrid operation. Forced oscillations, driven by periodic disturbances such as malfunctioning controllers [1], may resonate with poorly-damped natural modes across wide areas of the grid, and risk large system failures. Locating the source within the system is a prerequisite for mitigation schemes to correct the actions responsible for the original oscillation. We introduce a model-enhanced method for locating the source of a forced oscillation using PMU measurements. This method augments the use of data-only approaches, such as the energy based function inspired dissipating energy flow method. The algorithms are tested on several scenarios using a 240-bus,178-line WECC model.