Resettable MEMS micro-switch array based on current limiting apparatus

• US 8,072,723 B2
• Filed: 06/19/2007
• Issued: 12/06/2011
• Est. Priority Date: 06/19/2007
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Premerlani, William James, Caggiano, Robert Joseph, Subramanian, Kanakasabapathi, Kumfer, Brent Charles, Pitzen, Charles Stephan, Lesslie, David James, Wright, Joshua Isaac, Thakre, Parag
• Primary Examiner(s): PATEL, DHARTI HARIDAS
• Application Number:
  US11/764,908
• Publication Number:
  US 20080316664A1
• Time in Patent Office: 1,631 Days
• Field of Search: 361/87
• US Class Current: 361/87
• CPC Class Codes: H01H 2071/008 Protective switches or relays using micromechanics
• CPC Class Codes: H01H 59/0009 making use of micromechanics
• CPC Class Codes: H01H 9/541 Contacts shunted by semiconductor devices

Abstract

The present invention comprises a method for over-current protection. The method comprising monitoring a load current value of a load current passing through a plurality of micro-electromechanical switching system devices, determining if the monitored load current value varies from a predetermined load current value, and generating a fault signal in the event that the monitored load current value varies from the predetermined load current value. The method also comprises diverting the load current from the plurality of micro-electromechanical switching system devices in response to the fault signal and determining if the variance in the load current value was due to a true fault trip or a false nuisance trip.

Claims

1. A method for over-current protection, the method comprising:

monitoring a load current value of a load current passing through a plurality of micro-electromechanical switching system devices;

determining if the monitored load current value varies from a predetermined load current value;

generating a fault signal in the event that the monitored load current value varies from the predetermined load current value;

diverting the load current from the plurality of micro-electromechanical switching system devices in response to the fault signal;

opening the plurality of micro-electromechanical switching system devices in response to the diverting; and

determining if the variance in the load current value was due to a true fault trip or a false nuisance trip.

2. The method of claim 1, wherein if it is determined that the variance in the load current value was due to a true fault trip, then the switches of the micro-electromechanical switching devices will remain open.

3. The method of claim 2, wherein if it is determined that the variance in the load current value was due to a false nuisance trip, then the switches of the micro-electromechanical switching devices will be closed.

4. The method of claim 3, further comprising monitoring a load voltage value.

5. The method of claim 4, further comprising determining if the monitored load voltage value varies from a predetermined load voltage value.

6. The method of claim 5, further comprising generating a fault signal in the event that the monitored load voltage/current value varies from the predetermined load voltage value.

7. The method of claim 6, further comprising determining if the variance in the load voltage/current value was due to a true fault trip or a false nuisance trip.

8. The method of claim 1, further comprising initiating a pulse circuit current in response to the generated fault signal.

9. The method of claim 8, where in response to the diversion of the load current the switches of the plurality of micro-electromechanical switching devices are opened.

10. An over-current protective device for electrical distribution systems, the device comprising:

a user interface, wherein the user interface is configured to receive input control commands, the user interface further comprising a terminal block and a disconnect switch, the terminal block being in communication with the disconnect switch;

a logic circuit in communication with the user interface;

a power stage circuit in communication with the logic circuit;

a MEMS protection circuit in communication with the logic circuit and the power stage circuit; and

a switching circuit in communication with the MEMS protection circuit, the switching circuit comprising a plurality of micro-electromechanical system switching devices;

wherein,

the logic circuit is disposed to monitor a load current or load voltage, and in response to the monitored load current or load voltage varying from a predetermined value, the logic circuit is configured to generate and transmit a fault signal to the MEMS protection circuit and determine if the monitored current or voltage was in response to a true fault trip or a false nuisance trip;

the MEMS protection circuit is disposed to divert a load current from micro-electromechanical system switching devices in response to the fault signal; and

the switching circuit is configured to open the plurality of micro-electromechanical switching system devices in response to diversion of the load current by the MEMS protection circuit.

11. The device of claim 10, wherein the plurality of micro-electromechanical system switching devices of the switching circuit are in communication with the disconnect switch of the user interface.

12. The device of claim 10, where the micro-electromechanical system switches are opened in response to the diversion of the load current.

13. The device of claim 12, wherein the switching circuit further comprises an isolator contactor that is in communication with the plurality of micro-electromechanical system switching devices, the isolator contactor being configured to isolate a line to a load in response to the switches of the plurality of micro-electromechanical system switching devices being in an open position.

14. The device of claim 13, wherein if it is determined that the varying in the current load value was due to a true fault trip, then the switches of the micro-electromechanical switching devices will remain open.

15. The device of claim 14, wherein if it is determined that the varying in the current load value was due to a false nuisance trip, then the switches of the micro-electromechanical switching devices will be closed.