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1. WO2016149699 - SECURED FAULT DETECTION IN A POWER SUBSTATION

Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

[ EN ]

CLAIMS

1. A method comprising:

detecting a fault in a power system;

detecting one or more fault transients; and

determining to trip a switching device of a power system in response to the detected fault and the detected one or more fault transients.

2. The method of claim 1, wherein the step of detecting the fault comprises detecting the fault from first sampled data for a first monitored point in the power system, the first sampled data comprising at least one of a first sampled current data and a first sampled voltage data, and wherein the step of detecting one or more fault transients comprises detecting one or more fault transients using second sampled data for a second monitored point in the power system, the second sampled data comprising at least one of a second sampled current data and a second sampled voltage data.

3. The method of claim 2, wherein the step of detecting the fault comprises detecting the presence of the fault using phasor calculations.

4. The method of claim 3, wherein the step of detecting the one or more fault transients comprises:

high-pass filtering the second sampled data; and

determining whether the filtered second sampled data exceeds a pre-determined amplitude.

5. The method of claim 1, wherein the step of detecting the fault is performed by a first monitoring device, and wherein the step of detecting the one or more fault transients is performed by one or more other monitoring devices.

6. The method of claim 5, further including the step of receiving, by the first monitoring device, an indication of the detection, by the one or more other monitoring devices, of the one or more fault transients.

7. The method of claim 6, wherein the step of determining to trip the switching device includes determining whether the first monitoring device received an indication of the detection of the one or more fault transients within a predetermined time period.

8. The method of claim 7, further including the steps of:

determining, by the first monitoring device and using first sampled data of a first monitoring point of the power system, a first fault direction of a first fault transient; and

determining, by the one or more other monitoring devices and using sampled data of at least a second monitoring point of the power system, a second fault direction of at least one of the one or more fault transients,

wherein the step of determining to trip the switching device includes determining whether the first fault direction is consistent with the second fault direction.

9. The method of claim 8, wherein determining the first fault direction comprises:

calculating an instantaneous energy direction for the first fault transient by obtaining a decoupled mode voltage and a decoupled mode current for each of several tracked fault component voltages and currents;

calculating instantaneous active power and instantaneous reactive power for each of the decoupled mode voltages and decoupled mode currents;

accumulating the instantaneous active powers and instantaneous reactive powers to form instantaneous active energies and reactive energies; and

evaluating the signs of the instantaneous active energies and reactive energies to determine the fault direction for the electromagnetic transient.

10. The method of claim 1, wherein the step of detecting the fault includes receiving, by a first monitoring device, first sampled data for a first monitored point in the power system and detecting the fault using the first sampled data, and wherein the step of detecting the one or more fault transients includes receiving second sampled data for a second monitored point and determining that the second sampled data indicates a fault transient at the second monitored point.

11. The method of claim 10, further including the steps:

determining a first direction for a first fault transient at the first monitored point; and determining a second direction for the fault transient at the second monitored point, wherein the step of determining to trip the switching device includes determining whether the first fault direction is consistent with the second fault direction.

12. A monitoring device for a power system, the monitoring device comprising:

a first interface circuit configured to receive a first sampled data of a first monitored point in the power system;

a signal processing circuit configured to detect, using the received first sampled data, a fault in the power system; and

a second interface circuit configured to receive at least one fault transient report from at least one other monitoring device, the at least one fault transient report indicating a detection at at least another monitored point of a fault transient,

wherein the signal processing circuit is further configured to, in response to the detection of the fault and receipt of the at least one fault transient report, determine whether to issue a command to trip a power system switching device of the power system.

13. The monitoring device of claim 12, wherein the signal processing circuit is configured to detect the fault using phasor calculations based on the first sampled data, and further wherein the first sampled data comprises at least one of a sampled current data and a sampled voltage data.

14. The monitoring device of claim 12, wherein the signal processing circuit is configured to detect the fault by detecting a first fault transient using the first sampled data, and wherein the first sampled data comprises at least one of a sampled current data and a sampled voltage data.

15. The monitoring device of claim 14, wherein the at least one fault transient report includes a second fault transient direction for the fault transient detected at the at least another monitored point, and wherein the signal processing circuit is further configured to determine a first fault transient direction for the first fault transient, and further wherein the signal processing circuit is configured to not issue a command to trip the power system if the second fault transient direction is inconsistent with the first fault transient direction.

16. The monitoring device of claim 15, wherein the signal processing circuit is configured to determine not to trip the power system switching device upon failing to receive, within a predetermined interval, the at least one fault transient report.

17. The monitoring device of claim 16, wherein the monitoring device further includes a high-pass filter configured to filter the first sampled data to produce a filtered first sampled data, and wherein the signal processing circuit is configured to detect the first fault transient by determining whether the filtered first sampled exceeds a pre-determined amplitude.

18. A method comprising:

receiving, by a monitoring device, sampled data for a monitored point in a power system; detecting, by the monitoring device and using the sampled data, an electromagnetic transient caused by a fault in the power system; and

reporting the detected electromagnetic transient to at least one other monitoring device.

19. The method of claim 18, wherein the step of detecting the electromagnetic transient comprises:

high-pass filtering the sampled data, the sampled data comprising at least one of a sampled current data and a sampled voltage data; and

determining whether the filtered sampled data exceeds a pre-determined amplitude.

20. The method of claim 19, further including the step of determining a fault direction for the detected electromagnetic transient, and wherein the step of reporting the detected electromagnetic transient includes reporting the determined fault direction.

21. A monitoring device comprising:

a first interface circuit configured to receive first sampled data of a first monitored point in a power system;

a signal processing circuit configured to detect, using the first sampled data received by the first interface circuit, an electromagnetic transient caused by a fault in the power system, the signal processing circuit further configured to report the detected electromagnetic transient to at least one additional monitoring device in the power system.

22. The monitoring device of claim 21, wherein the monitoring device further includes a high-pass filter configured to filter the first sampled data to produce a filtered first sampled data, and wherein the signal processing circuit is configured to detect the electromagnetic transient by determining whether the filtered first sampled data exceeds a pre-determined amplitude.

23. The monitoring device of claim 21, wherein the signal processing circuit is configured to determine a fault direction for the electromagnetic transient and report an indication of the determined fault direction to at least one additional monitoring device.