Small-signal Approximations of Frequency Estimation Algorithms

Estimates of power system frequency are beginning to be used in critical, real-time applications such as synthetic inertia. The behavior of the algorithms used to estimate frequency from point-on-wave signals can be complicated, and algorithm tuning difficult for non-experts. In this paper, small-signal approximations for four common frequency estimation algorithms are presented. These approximations are demonstrated to be both theoretically and empirically sound. They are valuable for three primary reasons: 1) they reduce the level of technical expertise required for effective tuning; 2) they effectively capture the dynamics of the algorithm so can be used as a proxy for the algorithm itself in the analysis of feedback control loops that employ frequency feedback; and 3) they can easily be implemented in transient stability simulation software in order to represent realistic frequency estimation.