Patent ID: 11882889
Assignee: UT-BATTELLE, LLC
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC A  G  H | IPC A  G  H

Claim 0:
1. An apparatus that determines in real time frequency of grid signals x(t) corresponding to an electrical grid comprising:
a transient detector configured to:
monitor a signal indicative of a grid signal x(k) from a voltage meter or current meter connected to the electrical grid, where the grid signal is expected to include a periodic signal with a nominal frequency fo and a sampling rate fs;

produce, in real time and at the sampling rate of the monitored signal, a deviation signal Xdev indicative of whether or not the monitored signal includes the periodic signal; and
determine, over one or more cycles, a measurement signal corresponding to the deviation signal; and
a frequency estimator communicatively linked with the transient detector, the frequency estimator configured to:
determine a frequency signal fe that corresponds to a frequency estimation of the monitored signal while values of the measurement signal are less than a deviation threshold; and
maintain the frequency signal at a constant value while values of the measured signal equal or exceed the deviation threshold;
where the transient detector is configured to transmit a flag to the frequency estimator indicating that the monitored signal:
comprises a periodic signal when values of the measurement signal are less than a deviation threshold expressed as γ<thr, where γ comprises a measurement of the deviation signal and thr comprises the deviation threshold; and
exhibits a transient when values of the measurement signal equal or exceed the deviation threshold expressed as γ≥thr.