High-impedance fault detection using coordinated devices
AssigneeSchweitzer Engineering Laboratories, Inc.
InventorShankar V. Achanta
Life of this patent
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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.
Claims23
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.
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.
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.
Dependencies are inferred from the claim text.