Power system detection of sustained oscillations based on synchrophasor frequency measurements
View Patent ↗A method includes performing by a processor: receiving a plurality of power system phase angle measurements over a time interval from a plurality of phasor measurement units (PMUs) in a power system, generating a phase angle curve over the time interval based on the plurality of power system phase angle measurements, and detecting a sustained oscillation event in a power signal generated by the power system based on an envelope of the phase angle curve.
1. A method comprising:
performing by a processor:
receiving a plurality of power system phase angle measurements over a time interval from a plurality of phasor measurement units (PMUs) in a power system;
generating a phase angle curve over the time interval based on the plurality of power system phase angle measurements; and
detecting a sustained oscillation event in a power signal generated by the power system based on an envelope of the phase angle curve.
2. The method of claim 1 , wherein detecting the sustained oscillation event comprises:
detecting the sustained oscillation event based on a magnitude of the envelope of the phase angle curve.
3. The method of claim 2 , wherein detecting the sustained oscillation event based on the magnitude of the envelope of the phase angle curve comprises:
determining a maximum peak-to-peak magnitude of the envelope of the phase angle curve;
comparing the maximum peak-to-peak magnitude of the envelope of the phase angle curve to a threshold; and
detecting the sustained oscillation event based on the maximum peak-to-peak magnitude of the envelope of the phase angle curve exceeding the threshold.
4. The method of claim 1 , wherein detecting the sustained oscillation event comprises:
detecting the sustained oscillation event based on a damping of the envelope of the phase angle curve.
5. The method of claim 4 , wherein detecting the sustained oscillation event based on the damping of the envelope of the phase angle curve comprises:
determining a first peak-to-peak magnitude of the envelope of the phase angle curve for a first cycle of the phase angle curve;
determining a second peak-to-peak magnitude of the envelope of the phase angle curve for a second cycle of the phase angle curve occurring later in time than the first cycle of the phase angle curve;
determining a ratio of the second peak-to-peak magnitude to the first peak-to-peak magnitude;
comparing the ratio to a threshold; and
detecting the sustained oscillation event based on the ratio exceeding the threshold.
6. The method of claim 1 , wherein detecting the sustained oscillation event comprises:
detecting the sustained oscillation event based on a magnitude of the envelope of the phase angle curve exceeding a magnitude threshold for a time duration that exceeds a time duration threshold.
7. The method of claim 6 , wherein the method further comprises:
determining a probability density function of the magnitude of the envelope of the phase angle curve;
wherein the magnitude threshold corresponds to a magnitude value of the envelope of the phase angle curve that is greater than other magnitude values of the envelope of the phase angle curve with a probability of about 99.5%.
8. The method of claim 1 , further comprising:
adjusting an assignment of a power generator to a load in the power system based on the sustained oscillation event.
9. A system, comprising:
a processor; and
a memory coupled to the processor and comprising computer readable program code embodied in the memory that is executable by the processor to perform operations comprising:
receiving a plurality of power system phase angle measurements over a time interval from a plurality of phasor measurement units (PMUs) in a power system;
generating a phase angle curve over the time interval based on the plurality of power system phase angle measurements; and
detecting a sustained oscillation event in a power signal generated by the power system based on an envelope of the phase angle curve.
10. The system of claim 9 , wherein detecting the sustained oscillation event comprises:
detecting the sustained oscillation event based on a magnitude of the envelope of the phase angle curve.
11. The system of claim 10 , wherein detecting the sustained oscillation event based on the magnitude of the envelope of the phase angle curve comprises:
determining a maximum peak-to-peak magnitude of the envelope of the phase angle curve;
comparing the maximum peak-to-peak magnitude of the envelope of the phase angle curve to a threshold; and
detecting the sustained oscillation event based on the maximum peak-to-peak magnitude of the envelope of the phase angle curve exceeding the threshold.
12. The system of claim 9 , wherein detecting the sustained oscillation event comprises:
detecting the sustained oscillation event based on a damping of the envelope of the phase angle curve.
13. The system of claim 12 , wherein detecting the sustained oscillation event based on the damping of the envelope of the phase angle curve comprises:
determining a first peak-to-peak magnitude of the envelope of the phase angle curve for a first cycle of the phase angle curve;
determining a second peak-to-peak magnitude of the envelope of the phase angle curve for a second cycle of the phase angle curve occurring later in time than the first cycle of the phase angle curve;
determining a ratio of the second peak-to-peak magnitude to the first peak-to-peak magnitude;
comparing the ratio to a threshold; and
detecting the sustained oscillation event based on the ratio exceeding the threshold.
14. The system of claim 9 , wherein detecting the sustained oscillation event comprises:
detecting the sustained oscillation event based on a magnitude of the envelope of the phase angle curve exceeding a magnitude threshold for a time duration that exceeds a time duration threshold.
15. The system of claim 9 , wherein the operations further comprise:
adjusting an assignment of a power generator to a load in the power system based on the sustained oscillation event.
16. A computer program product, comprising:
a tangible computer readable storage medium comprising computer readable program code embodied in the medium that is executable by a processor to perform operations comprising:
receiving a plurality of power system phase angle measurements over a time interval from a plurality of phasor measurement units (PMUs) in a power system;
generating a phase angle curve over the time interval based on the plurality of power system phase angle measurements; and
detecting a sustained oscillation event in a power signal generated by the power system based on an envelope of the phase angle curve.
17. The computer program product of claim 16 , wherein detecting the sustained oscillation event comprises:
detecting the sustained oscillation event based on a magnitude of the envelope of the phase angle curve.
18. The computer program product of claim 16 , wherein detecting the sustained oscillation event comprises:
detecting the sustained oscillation event based on a damping of the envelope of the phase angle curve.
19. The computer program product of claim 16 , wherein detecting the sustained oscillation event comprises:
detecting the sustained oscillation event based on a magnitude of the envelope of the phase angle curve exceeding a magnitude threshold for a time duration that exceeds a time duration threshold.
20. The computer program product of claim 16 , wherein the operations further comprise:
adjusting an assignment of a power generator to a load in the power system based on the sustained oscillation event.