Integration of phase-locked loop based real-time oscillation tracking in grid synchronized systems

This paper discusses how a real-time electromechanical oscillation monitoring system (REOMS) can be incorporated into synchrophasor devices. Using a closed loop feedback system consisting of a second order generalized integrator phase-locked loop (SOGI-PLL), this paper shows that real-time frequency, phase, and magnitude of electromechanical oscillations can be tracked using existing synchronized measurement platforms. The approach is demonstrated using simulation and a scaled hardware demonstration platform developed by the Center for Ultra-wide-area Resilient Electric Energy Transmission Networks (CURENT) to test wide-area monitoring and control schemes. Compared to traditional spectral base techniques, the phase lock loop approach offers more flexibility in tracking realtime oscillations, especially when the signal has floating modal properties. Real-time tracking of oscillation becomes extremely important when trying to adopt wide-area control schemes into the power grid, specifically oscillation damping and angular stability.