Inter-area oscillation detection

1. A system for detecting inter-area oscillations between power systems, the system comprising a memory and a processor, the memory storing instructions that configure the processor to:

receive data related to measurements of characteristics of electricity passing through one or more power lines;

filter the received data;

validate the filtered data by performing a time domain validation check and a dead band frequency check, the time domain validation check including determining whether the filtered data lie in a predetermined frequency band, and the dead band frequency check including determining whether a number of consecutive positive samples of the filtered data and a number of consecutive negative samples of the filtered data are within a predetermined limit;

estimate, in response to the filtered data being validated, an oscillation frequency of the filtered data; and

estimate a magnitude of the inter-area oscillations between the power systems based on the estimated oscillation frequency.

2. The system of claim 1 , wherein the processor is further configured to transmit an alarm based on a comparison between the estimated magnitude and a threshold value.

3. The system of claim 1 , wherein the processor is further configured to transmit a trip signal to interrupt power transmission on the one or more power lines based on a comparison between the estimated magnitude and a threshold value.

4. The system of claim 1 , wherein the system comprises interface circuitry configured to interrupt power transmission on the one or more power lines based on a comparison between the estimated magnitude and a threshold value.

5. The system of claim 1 , wherein the processor is further configured to estimate the oscillation frequency using a time-domain frequency estimation method including:

(i) determining a raw frequency of an oscillation to be determined,

(ii) calculating an average frequency of the oscillation, and

(iii) determining a total number of samples for a full oscillation period.

6. The system of claim 1 , further comprising a subsystem configured to:

receive other data related to measurements of characteristics of electricity passing through the one or more power lines; and

transmit the other data to the processor.

7. A non-transitory computer readable medium for detecting inter-area oscillations between power systems, the computer-readable medium comprising instructions that, when executed by a processor, cause the processor to perform operations comprising:

receiving data related to measurements of characteristics of electricity passing through one or more power lines;

filtering the received data;

validating the filtered received data by performing a time domain validation check and a dead band frequency check, the time domain validation check including determining whether the filtered data lie in a predetermined frequency band, and the dead band frequency check including determining whether a number of consecutive positive samples of the filtered received data and a number of consecutive negative samples of the filtered data are within a predetermined limit;

estimating, in response to the filtered data being validated, an oscillation frequency of the filtered data;

estimating a magnitude of the inter-area oscillations based on the estimated oscillation frequency;

comparing the estimated magnitude with a threshold value; and

generating, based on a result of the comparing, a trip signal for interrupting power transmission on the one or more power lines.

8. The non-transitory computer readable medium of claim 7 , wherein the operations further comprise generating an alarm signal based on the result.

9. The non-transitory computer readable medium of claim 7 , wherein the validating includes determining whether consecutive positive AC samples of the filtered received data exceed a first threshold and whether magnitudes of consecutive negative AC samples of the filtered received data exceed a second threshold.

10. The non-transitory computer readable medium of claim 7 , wherein the validating includes determining whether the received data includes a low-magnitude noise signal.

11. The non-transitory computer readable medium of claim 7 , wherein the validating includes determining whether other data received during a period previous to a current period have been oscillatory.

12. The non-transitory computer readable medium of claim 7 , wherein estimating the oscillation frequency comprises using a time-domain frequency estimation method including:

estimating a raw frequency of an oscillation to be determined;

calculating an average frequency of the oscillation; and

determining a total number of samples for a full oscillation period.

13. A device for detecting inter-area oscillation between power systems, the device comprising:

interface circuitry configured to receive data related to measurement of characteristics of electricity passing through a first power line;

filtering circuitry configured to remove a power system frequency component from the data to yield filtered data;

validating circuitry configured to perform a time domain validation check and a dead band frequency check, the time domain validation check including determining whether the filtered data lie in a predetermined frequency band, and the dead band frequency check including determining whether a number of consecutive positive samples of the filtered data and a number of consecutive negative samples of the filtered data are within a predetermined limit; and

a processor configured to (i) estimate an oscillation frequency from the filtered data and (ii) estimate a magnitude of the inter-area oscillations based on the estimated oscillation frequency.

14. The device of claim 13 , wherein the processor is configured to generate one of an alarm signal and a trip signal based on a comparison between the estimated magnitude and a predetermined threshold value.

15. The device of claim 14 , comprising a network interface circuit configured to transmit one of the alarm signal and the trip signal.

16. The device of claim 13 , comprising a network interface circuit configured to receive other data related to measurements of characteristics of electricity passing through a second power line.

17. The device of claim 16 , wherein the filtering circuitry is configured to remove a power system frequency component from the other data to yield other filtered data, and wherein the processor is configured to estimate another oscillation frequency from the second filtered data using a time-domain frequency estimation method.

18. The system of claim 1 , wherein the processor is further configured to remove a power system frequency component from the received data to extract 0.1 Hz to 1.0 Hz frequency signals.

19. The non-transitory computer readable medium of claim 7 , wherein the operations further comprise removing a power system frequency component form the received data to extract 0.1 Hz to 1.0 Hz frequency signals.