Online Oscillations Management at ISO New England

Installation of Phasor Measurement Unit (PMU) infrastructure in the ISO New England (ISO-NE) power system in 2012 has enabled monitoring of the actual dynamic behavior of the system. Multiple instances of oscillations in the frequency range from 0.05 to 2 Hz with significant MW magnitude and lasting from few seconds to hours have been observed. Majority of these oscillations can be classified as “forced oscillations” and caused mainly by the failure of equipment, failure or inappropriate settings of control systems or unplanned operating conditions. Forced oscillations represent the threat to the power system security and need to be mitigated. The critical step in the successful mitigation is finding the source of oscillations which is typically a specific generator or a power plant. The chapter describes the oscillations observed in the ISO-NE power system, forced oscillation mitigation, and the Oscillation Source Locating (OSL) application which is an online tool for the robust estimation of the source of sustained oscillations.