High-impedance fault detection using coordinated devices

Patent metadata

Field	Value
Publication number	US-10649020-B2
Application number	US-201715590164-A
Country	US
Kind code	B2
Filing date	May 9, 2017
Priority date	May 16, 2016
Publication date	May 12, 2020
Grant date	May 12, 2020

Abstract

A conductor-mounted device (CMD) used to signal an intelligent electronic device (IED) of the existence of a fault on a portion of the electric power delivery system is described herein. The CMD may provide a heartbeat signal to the IED. The CMD may provide a fault signal to the IED. The CMD may be powered via a parasitic current draw on the conductor to which it is mounted. An IED may use a fault signal and/or LOC signal from a CMD to coordinate a high-impedance fault detection and/or downed line events.

First claim

What is claimed:

1. A conductor mounted device, comprising:
a clamp assembly to secure the mounting device to a conductor;
a current transformer coupled to the conductor to produce a secondary current proportional to a primary current in the conductor;
a heartbeat circuit stage to generate a heartbeat signal indicating that the conductor mounted device is functional;
a state determination circuit to determine a state of the conductor independent of the heartbeat signal;
a transmitter to
wirelessly transmit the heartbeat signal on a periodic basis, and
wirelessly transmit the conductor state in response to a determined change in the conductor state separate from the wirelessly transmitted heartbeat signal; and

a power supply to
receive at least a portion of the secondary current to charge a power store, and
supply power to at least the transmitter of the conductor mounted device.

2. The device of claim 1 , wherein the current transformer comprises a pole piece that extends from the conductor mounted device proximate the conductor.

3. The device of claim 1 , wherein the clamp assembly comprises at least one clamping arm that pivots via a pivot member.

4. The device of claim 1 , further comprising:
a human machine interface (HMI) oriented toward the ground when the conductor mounted device is mounted to the conductor, the HMI comprising at least one display element.

5. The device of claim 1 , wherein the transmitter comprises a wireless RF transmitter, and wherein the conductor mounted device further comprises an antenna connected to the transmitter.

6. The device of claim 1 , wherein the power store comprises one of a capacitor and a battery, and wherein the power supply comprises a rectifier to rectify the secondary current to charge the power store.

7. The device of claim 6 , wherein the power supply is further configured to supply power to the heartbeat circuit stage and the state determination circuit.

8. The device of claim 1 , further comprising a timing circuit to cause the heartbeat circuit stage to transmit the heartbeat signal on a periodic basis via the transmitter.

9. The device of claim 1 , wherein the state determination circuit comprises a comparator circuit stage to receive at least a portion of the secondary current to identify a conductor state as at least one of a loss of load current (LOC) state and a fault state.

10. The device of claim 9 , wherein the comparator circuit stage comprises an operational amplifier to compare a voltage derived from the secondary current with a reference voltage from the power supply.

11. The device of claim 1 , wherein the state determination circuit comprises:
a monitoring sensor to monitor a characteristic of the conductor and output sensor data; and
a comparator circuit stage to receive the sensor data and identify a conductor state as one of normal and abnormal.

12. The device of claim 11 , wherein the monitoring sensor is configured to monitor a characteristic of the conductor comprising at least one of: a temperature of the conductor, a temperature proximate the conductor, a wind speed proximate the conductor, acceleration of the conductor, an acoustic of the conductor, and a sag of the conductor.

13. A fault monitoring system, comprising:
a conductor mounted device (CMD) to be coupled to a first conductor of an electric power system, the CMD including:
a mounting device to mount the CMD to the first conductor;
a CMD current transformer to measure a current in the first conductor;
a fault detector in communication with the current transformer to detect a fault in the first conductor; and
a transmitter to wirelessly transmit:
a fault signal indicating that a fault has been detected in response to detection of a fault by the fault detector, and
a heartbeat signal on a periodic basis independent of the fault signal; and

an intelligent electronic device (IED) to receive communications from the CMD and implement at least one protective action, the IED including:
a receiver to receive the transmitted signal from the CMD indicating that a fault has been detected on the first conductor;
an IED current transformer monitoring a current on a second conductor electrically connected to the first conductor; and
a protective action component to determine a protective action to be taken based on the monitored current on the second conductor from the IED current transformer and the fault signal from the CMD.

14. The system of claim 13 , wherein the CMD current transformer comprises a pole piece that extends from a body of the CMD proximate the conductor, and wherein the CMD current transformer is configured to parasitically produce a secondary current proportional to the current in the first conductor.

15. The system of claim 14 , wherein the parasitically produced secondary current is used to power the CMD obviating the need for direct external power.

16. The system of claim 15 , wherein the parasitically produced secondary current is used to charge a power store, and wherein the power store is configured to continue to provide power to at least a portion of the CMD upon a loss of load current (LOC) event of the first conductor.

17. The system of claim 16 , wherein the CMD further includes a rectifier and wherein the power store comprises at least one of a capacitor and a battery.

18. The system of claim 13 , wherein the transmitter comprises a wireless RF transmitter, and wherein the CMD further includes an antenna connected to the transmitter.

19. The system of claim 13 , wherein the CMD further comprises a heartbeat generator to send, via the transmitter, a heartbeat signal to the IED on an established periodic basis confirming an operational state of the CMD, and wherein the IED is configured to alarm in the event a predetermined number of heartbeat signals are not received from the CMD per the periodic basis.

20. A method for identifying a fault, comprising:
securing a conductor mounted device to a conductor of an electric power system;
producing, via a current transformer, a secondary current for use by the conductor mounted device that is proportional to a primary current in the conductor;
transmitting, via a transmitter, a heartbeat signal periodically to indicate that the conductor mounted device is functional;
determining a state of the conductor as at least one of a loss of load current (LOC) state and a fault state; and
transmitting the state of the conductor to a protective intelligent electronic device (IED) in response to a change in the state of the conductor independent of the heartbeat signal.

21. The method of claim 20 , further comprising:
powering the transmitter using power from the secondary current produced by the current transformer.

22. The method of claim 21 , further comprising:
storing a portion of the secondary current in a power store, wherein the power store is used to continue to supply power to the transmitter during a LOC state.

23. The method of claim 22 , further comprising:
rectifying at least the portion of the secondary current before storing it in the power store, and wherein the power store comprises at least one of a capacitor and a battery.

Assignees

• Schweitzer Engineering Lab Inc

Inventors

• Achanta Shankar V

Classifications

• H02H7/261

  involving signal transmission between at least two stations (transmission of signals in general H02H1/0061) · CPC title

• G01R31/085 Primary

  in power transmission or distribution lines, e.g. overhead · CPC title

• H02H3/033

  with several disconnections in a preferential order, {e.g. following priority of the users, load repartition}(H02H3/06 takes precedence) · CPC title

• H02H3/52

  responsive to the appearance of harmonics · CPC title

• H02H3/08

  responsive to excess current (responsive to abnormal temperature caused by excess current H02H5/04) · CPC title