Wide range current monitoring system and method for electronic trip units

Patent metadata

Field	Value
Publication number	US-9716379-B2
Application number	US-201514840272-A
Country	US
Kind code	B2
Filing date	Aug 31, 2015
Priority date	Aug 31, 2015
Publication date	Jul 25, 2017
Grant date	Jul 25, 2017

Abstract

A circuit interrupter that includes a passive integration channel structured to receive an output signal from a di/dt current sensor and generate a first signal output based on the output signal, and an active integration channel structured to receive the output signal from the di/dt current sensor and generate a second signal output based on the output signal that is proportional to the primary current received by the di/dt current sensor. Circuit protection functionality is provided based on the first signal output responsive to the primary current being determined to be greater than a threshold level, current metering and circuit protection functionality is provided based on the second signal output responsive to the primary current being determined to be less than or equal to the threshold level, and a seed current value is provided to the active integrator based on the first signal output.

First claim

What is claimed is:

1. A circuit interrupter, comprising:
a passive integration channel including a passive integration circuit, wherein the passive integration channel is structured to receive an output signal from a di/dt current sensor and generate a first signal output based on the output signal that is proportional to a primary current received by the di/dt current sensor;
an active integration channel including an active integrator, wherein the active integration channel is structured to receive the output signal from the di/dt current sensor and generate a second signal output based on the output signal that is proportional to the primary current received by the di/dt current sensor;
a control system, wherein the control system stores and is structured to execute a number of routines, the number of routines being structured to:
provide circuit protection functionality for the circuit interrupter based on the first signal responsive to the primary current being determined to be greater than a threshold level;
provide current metering and circuit protection functionality for the circuit interrupter based on the second signal output responsive to the primary current being determined to be less than or equal to the threshold level; and
provide a seed current value to the active integrator based on the first signal output.

2. The circuit interrupter according to claim 1 , wherein the routines are structured to provide the seed current value to the active integrator responsive to a startup or reset of the control system or responsive to a comparison of a magnitude of the primary current to the threshold level.

3. The circuit interrupter according to claim 1 , wherein the di/dt current sensor is part of the circuit interrupter.

4. The circuit interrupter according to claim 1 , wherein the active integration channel includes an analog-to-digital converter which is structured to receive the output signal from the di/dt current sensor and generate the second signal output.

5. The circuit interrupter according to claim 4 , wherein the analog-to-digital converter is a sigma-delta converter.

6. The circuit interrupter according to claim 1 , wherein the active integrator is provided as part of a processing device of the control system.

7. The circuit interrupter according to claim 1 , wherein the passive integration channel includes includes a variable gain circuit coupled to the passive integration circuit.

8. The circuit interrupter according to claim 1 , wherein the passive integration circuit comprises a resistor and a capacitor.

9. The circuit interrupter according to claim 1 , wherein the passive integration channel includes an analog-to-digital converter which is structured receive an output from the passive integration circuit and generate the first signal output based on the output from the passive integration circuit.

10. The circuit interrupter according to claim 4 , wherein the analog-to-digital converter is provided as part of a processing device of the control system.

11. The circuit interrupter according to claim 1 , further comprising a set of separable contacts and an operating mechanism operatively coupled to the set of separable contacts, and wherein the passive integration channel, the active integration channel and the control system are provided as part of a trip unit structured to provide a trip signal to the operating mechanism.

12. A method of operating a circuit interrupter, comprising:
receiving an output signal from a di/dt current sensor and generating a first signal output based on the output signal that is proportional to a primary current received by the di/dt current sensor using a passive integration channel including a passive integration circuit;
receiving the output signal from the di/dt current sensor and generating a second signal output based on the output signal that is proportional to the primary current received by the di/dt current sensor using an active integration channel including an active integrator;
providing circuit protection functionality for the circuit interrupter based on the first signal output responsive to the primary current being determined to be greater than a threshold level;
providing current metering and circuit protection functionality for the circuit interrupter based on the second signal output responsive to the primary current being determined to be less than or equal to the threshold level; and
providing a seed current value to the active integrator based on the first signal output.

13. The method according to claim 12 , wherein the seed current value is provided to the active integrator responsive to a startup or reset of the control system or responsive to the primary current being determined to be greater than the threshold level and thereafter being determined to be less than or equal to the threshold level.

Assignees

• Eaton Corp

Inventors

• Miller Theodore James
• Hosko Daniel A
• GAO George

Classifications

• H01H71/123

  using a solid-state trip unit (circuits H02H) · CPC title

• H02H1/0046

  Commutating the detecting means in dependance of the fault, e.g. for reducing their number · CPC title

• H01H83/00

  Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current · CPC title

• H02H1/0007

  concerning the detecting means (in general G01R or other subclasses of G01; reed switches H01H71/2445) · CPC title

• G01R15/181

  using coils without a magnetic core, e.g. Rogowski coils · CPC title