Proposals and Analysis of Space Vector-Based Phase-Locked-Loop Techniques for Synchrophasor, Frequency, and ROCOF Measurements

Space vector (SV)-based estimation algorithms represent attractive methods for synchronized phasor, frequency, and rate of change of frequency measurements in three-phase ac power systems. Recently, a phase-locked-loop (PLL) solution for improving the demodulation of the SV signal has been proposed. In this article, the potentialities of the SV-PLL approach are investigated in order to optimize accuracy and computational load. First, the impact of the PLL update rate on achieved performance is analyzed. Then, a novel two-step SV-PLL algorithm is presented so that the accuracy of a fast PLL execution frequency can be matched with a considerably lower computational cost. The behavior in the case of fast phase angle variations has been also significantly improved. The proposed synchrophasor estimation technique has been validated through simulations; exemplary dynamic performance suggests that it is particularly suitable for grid control applications. Experimental tests carried out on a real-time implementation confirm simulation results.