Protective device with multi-channel line current differential protection

A protection system for multi-channel differential protection of first and second transmission line segments, comprising:

• first and second intelligent electronic devices (IEDs) positioned at a first end of the first and second transmission line segments, each of the first and second IEDs including:
• a sensor subsystem to obtain current measurement data for the first ends of each of the first and second transmission line segments;
• a communication interface to:
• receive current measurement data for the second ends of the first and second transmission line segments from each of a third IED and a fourth IED, and
• transmit the obtained current measurement data for the first ends of the first and second transmission line segments to each of the third and fourth IEDs;
• a first differential protection subsystem to detect a fault condition based on a comparison of the current measurement data for the first end of the first transmission line segment and the current measurement data for the second end of the first transmission line segment;
• a second differential protection subsystem to detect a fault condition based on a comparison of the current measurement data for the first end of the second transmission line segment and the current measurement data for the second end of the second transmission line segment;
• a coordination interface to facilitate coordination communications between the first and second IEDs;
• and
• a coordinated protection subsystem operable to selectively implement coordinated protective actions on the first and second transmission line segments based on the coordination communications between the first and second IEDs,
• wherein each differential protection subsystem of each of the first and second IEDs is configured to implement an internal voting scheme based on two independent differential channels corresponding to (i) the current measurement data for the second end of a corresponding transmission line segment received from the third IED and (ii) the current measurement data for the second end of the corresponding transmission line segment received from the fourth IED, and to detect the fault condition in response to both independent differential channels detecting the fault condition.

An intelligent electronic device (IED) to provide multi-channel differential protection to N adjacent transmission lines, where Nis an integer, the IED comprising:

• a local sensor subsystem to obtain local current measurement data for a first end of each of the N transmission lines;
• a communication interface to receive remote current measurement data for a second end of each of the N transmission lines from a plurality of remote IEDs positioned proximate to the second ends of the N transmission lines;
• N differential protection subsystems, wherein each differential protection subsystem operates to detect a fault condition on one of the N transmission lines based on a comparison of local current measurement data for the first end of each respective transmission line and the remote current measurement data for the second end of each respective transmission line, and wherein at least one of the N differential protection subsystems comprises two independent differential channels operating concurrently to protect the same one of the N transmission lines, and wherein the at least one differential protection subsystem detects the fault condition based on outputs of the two independent differential channels being ANDed together by an internal voting scheme within the IED;
• a local coordination subsystem to facilitate coordination communications with a plurality of local IEDs positioned proximate to the first ends of the N transmission lines, the coordination communications including at least one of (i) received remote current measurement data and (ii) detected fault conditions;
• and
• a coordinated protection subsystem operable to implement a protective action on any of the N transmission lines based on a fault detection by a corresponding differential protection subsystem and the coordination communications.

An intelligent electronic device (IED) to provide differential protection, comprising:

• a local sensor subsystem to obtain local differential current measurement data for a first end of a power line segment;
• a communication interface to receive remote differential current measurement data for a second end of the power line segment from a remote IED;
• a differential protection subsystem to detect a fault condition based on an analysis of the local differential current measurement data for the first end of the power line segment and the remote differential current measurement data for the second end of the power line segment from the remote IED, wherein the differential protection subsystem utilizes a voting scheme to detect the fault condition in response to a discrepancy between the local differential current measurement data and the remote differential current measurement data, the voting scheme comprising using two independent differential channels to AND their outputs together before declaring the fault condition;
• and
• a protection subsystem operable to implement a protective action on the power line segment in response to fault detection by the differential protection subsystem.