초록 ▼

An intelligent electronic device may provide restricted earth fault protection to components of an electrical power delivery system using both an amplitude comparator and a phase angle comparator configured to independently detect faults. The IED may include selection logic configured to select the

An intelligent electronic device may provide restricted earth fault protection to components of an electrical power delivery system using both an amplitude comparator and a phase angle comparator configured to independently detect faults. The IED may include selection logic configured to select the output of one of the phase angle comparator and the amplitude comparator, to the exclusion of the other, based on system conditions. Accordingly, when system conditions are such that a phase angle comparator is better suited to detect a fault, selection logic may select the output of the phase angle comparator. Similarly, when system conditions are such that an amplitude comparator may better detect a fault, selection logic may select the output of the amplitude comparator. A protection system may further include an in-zone fault detector configured to detect in-zone faults.

대표청구항 ▼

1. An intelligent electronic device (IED) for providing restricted earth fault protection comprising: a phase angle comparator configured to receive an input comprising a vector representing electrical conditions associated with a plurality of phases of a mufti-phase electrical power delivery system

1. An intelligent electronic device (IED) for providing restricted earth fault protection comprising: a phase angle comparator configured to receive an input comprising a vector representing electrical conditions associated with a plurality of phases of a mufti-phase electrical power delivery system and a vector representing electrical conditions associated with a neutral line of the mufti-phase electrical power delivery system, to determine a phase angle difference between the input and a phase angle reference, and to selectively generate a phase angle comparator fault indicator based on the phase angle difference with respect to a phase angle deviation threshold;an amplitude comparator configured to receive the input and to selectively generate an amplitude comparator fault indicator based on the input with respect to an amplitude threshold; andselection logic configured to generate a selection logic output corresponding to one of the phase angle comparator fault indicator and the amplitude comparator fault indicator, to the exclusion of the other, based on a selection logic threshold, and the input from the mufti-phase electrical power delivery system. 2. The IED of claim 1, wherein the vector representing electrical conditions associated with the plurality of phases associated with the multi-phase electrical power delivery system comprises a zero-sequence current vector calculated from the currents of each phase in a three phase power system. 3. The IED of claim 1, wherein the input representing electrical conditions associated with a mufti-phase electrical power delivery system comprises a vector representing current. 4. The IED of claim 1, further comprising: in-zone fault detection logic configured to selectively generate an in-zone fault detection signal based on the input with respect to the amplitude comparator fault indicator, a first threshold, and a second threshold, the first threshold and the second threshold comprising boundaries of an in-zone fault range. 5. The IED of claim 4, wherein the first threshold is a minimum load current and the second threshold is a maximum current transformer saturation current. 6. The IED of claim 1, further comprising a timer, the timer comprising a timer output and a timer input, wherein the timer input is configured to receive the selection logic output, to determine that the selection logic output remains asserted for a specified period of time, and the timer is configured to selectively transmit the timer input to the timer output. 7. The IED of claim 1, wherein the selection logic threshold comprises a ratio of a measured current to a nominal current. 8. The IED of claim 1, further comprising IED interface logic configured to generate communications to be sent to a plurality of IEDs that contain instructions to be performed by one of the plurality of IEDs. 9. A method for providing restricted earth fault protection using an intelligent electronic device (IED) comprising: receiving an input from a mufti-phase electrical power delivery system;generating a vector representing electrical conditions associated with a plurality of phases of the mufti-phase electrical power delivery system;generating a vector representing electrical conditions associated with a neutral line of the mufti-phase electrical power delivery system;determining a phase angle difference between the input and a phase angle reference;generating a phase comparator fault indicator using a phase angle comparator based on the phase angle difference with respect to a phase angle threshold;generating an amplitude comparator fault indicator using an amplitude comparator based on the input with respect to an amplitude threshold; andgenerating a selection logic output using selection logic, the selection logic output corresponding to one of the phase angle comparator fault indicator and the amplitude comparator fault indicator, to the exclusion of the other, based on a selection logic threshold, and the input from the electrical power delivery system. 10. The method of claim 9, further comprising: representing the electrical conditions associated with the plurality of phases of the mufti-phase electrical power delivery system using a zero-sequence current vector calculated from the currents of each phase in a three phase power system. 11. The method of claim 9, wherein the vector representing electrical conditions associated with the plurality of phases of the mufti-phase electrical power delivery system comprises a vector representing current. 12. The method of claim 9, further comprising: generating an in-zone fault detection signal based on the input with respect to a first threshold and a second threshold, the first threshold and the second threshold comprising boundaries of an in-zone fault range, and the amplitude comparator fault indicator. 13. The method of claim 12, wherein the first threshold is a minimum load current and the second threshold is a maximum current transformer saturation current. 14. The method of claim 9, further comprising: receiving the selection logic output using a timer input;determining that the selection logic output remains asserted for a specified period of time; andselectively transmitting the timer input to the timer output. 15. The method of claim 9, wherein the selection logic threshold comprises a ratio of a measured current to a nominal current. 16. The method of claim 9, further comprising generating communications to be sent to a plurality of IEDs that contain instructions to be performed by one of the plurality of IEDs. 17. A computer system in an intelligent electronic device (IED) to identify faults in an electrical power delivery system, the computer system comprising: a processor; anda computer-readable storage medium in communication with the processor, the computer-readable storage medium comprising: a phase angle comparator module executable on the processor, the phase angle comparator module configured to receive an input comprising a vector representing electrical conditions associated with a plurality of phases of a mufti-phase electrical power delivery system and a vector representing electrical conditions associated with a neutral line of the multi-phase electrical power delivery system, and selectively generate a phase angle comparator fault indicator;an amplitude comparator module executable on the processor, the amplitude comparator module configured to receive the input and selectively generate an amplitude comparator fault indicator; anda selection logic module executable on the processor, the selection logic module configured to selectively transmit one of the phase angle comparator fault indicator and the amplitude comparator fault indicator to the exclusion of the other, based on a first threshold and the input from the electrical power delivery system. 18. The computer system of claim 17, wherein the computer-readable storage medium further comprises: an in-zone fault logic module executable on the processor, configured to selectively generate an in-zone fault detection signal based on the input with respect to the amplitude comparator fault indicator, a first threshold, and a second threshold, the first threshold and the second threshold comprising boundaries of an in-zone fault range. 19. The computer system of claim 17, wherein the computer-readable storage medium further comprises a timer module executable on the processor, to receive the selection logic output and to determine that the selection logic output remains asserted for a specified period of time, and to selectively transmit the selection logic output. 20. The computer system of claim 17, wherein the computer-readable storage medium further comprises an IED interface module executable on the processor, IED interface logic configured to generate communications to be sent to a plurality of IEDs that contain instructions to be performed by one of the plurality of IEDs.