A Comparative Study of Alternative Algorithms for Synchrophasor Estimation and Grid Synchronization

A critical challenge for the evolution of smart distribution systems is the shortage of measurement devices, along with the complexity and the high costs for deploying new fine-grained monitoring infrastructures. To address this issue, this paper investigates the feasibility of upgrading the grid synchronization algorithms running in the control unit of grid-following power converters to turn them into auxiliary embedded measurement devices supporting system observability. This goal can be achieved in two alternative ways: either by using an algorithm originally designed for a Phasor Measurement Unit (PMU) to perform grid synchronization or, conversely, by applying a grid synchronization technique for synchrophasor estimation. To compare advantages and disadvantages of either approach, both a 2-stage Tuned Lightweight version of the Taylor-Fourier Transform (2-stage TLTFT) algorithm and a Phase-Locked Loop embedding a custom Third-Order Generalized Integrator (TOGI-PLL) are analyzed both in the P Class PMU testing conditions specified in the IEEE Standard IEC/IEEE 60255-118-1:2018 and considering the requirements for grid connection reported in the IEEE Standard 1547-2023. Extensive simulation results show that the general idea of a joint solution for synchrophasor estimation and grid synchronization is viable in either way, although some improvement is needed. In particular, the 2-stage TLTFT algorithm generally returns more accurate results and shorter response times than the TOGI-PLL, but it is also more computationally demanding. Further simulations, based on a real power electronic converter model, confirm that, when either algorithm is used in the control loop for grid synchronization, the generated output voltage is stable.