A Synchrophasor Estimator Characterized By Attenuated Self-Interference and Robustness Against Dc Offsets: The Dcsogi Interpolated Dft

The second-order generalized integrator (SOGI), which can be used to attenuate the self-interference of the fundamental tone, is unable to fully reject DC offsets on the input signal. Consequently, the performance of any SOGI based synchrophasor estimation (SE) technique might be compromised in the presence of such DC components. The current work presents a SE algorithm which adopts an enhanced SOGI formulation, robust against DC, combined with a three-point IpDFT and a three nominal fundamental period Hanning observation window. Its simultaneous compliance with both phasor measurement unit (PMU) P and M performance classes is assessed by means of a simulated environment where all the operating conditions defined by the IEC/IEEE 60255-118-1:2018 standard are evaluated combined with a 10% static DC offset and under two different noise levels. Furthermore, the method adopts a dedicated mechanism for the detection of low amplitude 2nd harmonic tones and the correction of their impacts under off-nominal frequency conditions. Finally, its resilience against multiple simultaneous harmonic interferences is also analyzed together with its performance in the presence of decaying DC components.