Circuit breaker with integral testing unit

• US 6,798,209 B2
• Filed: 01/17/2002
• Issued: 09/28/2004
• Est. Priority Date: 01/17/2002
• Status: Active Grant

• Current Assignee: ABB SPA (ABB Limited)
• Original Assignee: General Electric Company
• Inventors: Fletcher, David, Lavoie, Gregory
• Primary Examiner(s): Le, N.
• Assistant Examiner(s): Benson, Walter
• Application Number:
  US10/052,904
• Publication Number:
  US 20030132753A1
• Time in Patent Office: 985 Days
• Field of Search: 324/424, 324/509, 324/536, 324/521, 761/42, 761/119, 361/97
• US Class Current: 324/424
• CPC Class Codes: G01R 31/327 Testing of circuit interrupters, switches or circuit-breakers
• CPC Class Codes: G01R 31/3277 of low voltage devices, e.g. domestic or industrial devices, such as motor protections, relays, rotation switches
• CPC Class Codes: H01H 2300/03 Application domotique, e.g. for house automation, bus connected switches, sensors, loads or intelligent wiring
• CPC Class Codes: H01H 71/123 using a solid-state trip unit circuits H02H
• CPC Class Codes: H01H 71/7409 Interchangeable elements
• CPC Class Codes: H02H 3/044 Checking correct functioning of protective arrangements, e.g. by simulating a fault for differential current circuit breakers H02H3/335
• CPC Class Codes: Y02B 70/30 Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
• CPC Class Codes: Y02B 90/20 Smart grids as enabling technology in buildings sector smart grids supporting the management or operation of end-user stationary applications in general, or like technologies with no associated climate change mitigation effect Y04S20/00
• CPC Class Codes: Y04S 20/14 Protecting elements, switches, relays or circuit breakers
• CPC Class Codes: Y04S 20/20 End-user application control systems

Abstract

An injection test signal generator is incorporated into a circuit breaker. In this way, injection testing can be performed by causing the internal test signal generator to generate test signals and feed those signals to the trip circuitry of the circuit breaker. No independent injection test signal generator need be purchased or stored, or transported to the location of the circuit breaker and hardwired thereto. Various methods of communicating with the internal test signal generator can be implemented, including, for example, a standard interface, a wireless interface or a network interface. Dences can also be provided to selectively isolate the internal test signal generator from the trip circuitry to prevent accidental and erroneous breaker trips.

Claims

1. A circuit breaker comprising:

a plurality of sensors;

trip circuitry;

a microprocessor for controlling the amplitude and phase of test signals; and

a test signal generator incorporated in said circuit breaker for providing analog test signals to said trip circuitry under control of said microprocessor, wherein said test signals mimic the signals that would be received from the sensors.

2. The circuit breaker of claim 1, wherein said test signal generator comprises a source for generating said test signals selected from the group consisting of:

a current source, a voltage source, and both a current source and voltage source.

3. The circuit breaker of claim 1, further comprising a standard interface connected to said microprocessor for connecting to a corresponding standard interface on a general purpose computing device, a general purpose computing device in connection with the standard interface wherein the connection is provided to receive at least one function from the general purpose computer device selected from the group consisting of:

issuing commands to the microprocessor to control the test cycle, and display results of the test.

4. The circuit breaker of claim 3, wherein said standard interface is a USB interface.

5. The circuit breaker of claim 3, wherein said standard interface is an IEEE 1394 interface.

6. The circuit breaker of claim 3, wherein said standard interface is an RS232 interface.

7. The circuit breaker of claim 1, further comprising a wireless interface connected to said microprocessor.

8. The circuit breaker of claim 7, wherein said wireless interface is a radio frequency transceiver.

9. The circuit breaker of claim 7, wherein said wireless interface is an infra-red transceiver.

10. The circuit breaker of claim 1, further comprising a network interface connected to said microprocessor for connecting said microprocessor to a data network.

11. The circuit breaker of claim 1, further comprising at least one switch in a connection between said trip circuitry and said test signal generator, said switch being controlled by said microprocessor, said switch being open when said trip circuitry is not being tested so as to prevent erroneous test signals from causing a response by said trip circuitry.

12. The circuit breaker of claim 1, further comprising:

a receptacle forming a gap in a connection between said trip circuitry and said test signal generator; and

a key for insertion in said receptacle to bridge said gap allowing communication between said trip circuitry and said test signal generator.

13. The circuit breaker of claim 12, wherein said key is a rating plug.

14. The apparatus of claim 2, wherein the voltage source and signal source are provided using an analog to digital converter driven with digital signals from the microprocessor.

15. The apparatus of claim 14, wherein the digital signals from the microprocessor represent waveforms including sinuisoidal waveforms.

16. A method of testing a circuit breaker comprising testing trip circuitry of said circuit breaker by generating analog test signals with a test signal generator that is incorporated in said circuit breaker and by controlling the amplitude and phase of the test signals to mimic the signals that would be received from circuit breaker sensors.

17. The method of claim 16, wherein said testing further comprises generating either a current or a voltage test signal with a current source or a voltage source of said test signal generator.

18. The method of claim 16, further comprising controlling said testing with a general purpose computing device connected to said circuit breaker through a standard interface.

19. The method of claim 16, further comprising controlling said testing with a general purpose computing device communicating with said circuit breaker through a wireless interface.

20. The method of claim 16, further comprising controlling said testing through a network to which said circuit breaker is connected via a network interface.

21. The method of claim 16, further comprising preventing erroneous test signals from causing a response by said trip circuitry with at least one switch in a connection between said trip circuitry and said test signal generator, said switch being controlled so as to be open when said trip circuitry is not being tested.

22. The method of claim 16, further comprising enabling said testing by inserting a key in a receptacle forming a gap in a connection between said trip circuitry and said test signal generator, said inserted key bridging said gap thereby allowing communication between said trip circuitry and said test signal generator.

23. The system of claim 16, further comprising means for preventing erroneous test signals from causing a response by said trip circuitry.

24. The system of claim 23, wherein said means for preventing erroneous test signals from causing a response by said trip circuitry comprise a switch in a connection between said trip circuitry and said test signal generator, said switch being controlled so as to be open when said trip circuitry is not being tested.

25. The system of claim 23, wherein said means for preventing erroneous test signals from causing a response by said trip circuitry comprise a key for insertion in a receptacle that forms a gap in a connection between said trip circuitry and said test signal generator, said key, when inserted, bridging said gap thereby allowing communication between said trip circuitry and said test signal generator.

26. The method of claim 16, wherein the voltage and current source are provided using an analog to digital converter driven with digital signals from a microprocessor.

27. The method of claim 26, wherein the digital signals from the microprocessor represent waveforms including sinuisoidal waveforms.

28. A system for testing a circuit breaker comprising

first means for generating analog test signals, said first means being incorporated in said circuit breaker;

and

second means for controlling the amplitude and phase of the test signal used in testing trip circuitry of said circuit breakers with said test signals.

29. The system of claim 28, said first means further comprise means for generating either current or voltage test signals or both.

30. The system of claim 28, further comprising means for controlling said testing with a general purpose computing device connected to said circuit breaker through a standard interface.

31. The system of claim 28, further comprising means for controlling said testing with a general purpose computing device communicating with said circuit breaker through a wireless interface.

32. The system of claim 28, further comprising means for controlling said testing through a network to which said circuit breaker is connected via a network interface.

33. The system of claim 28, wherein the means for controlling includes voltage and current sources wherein the voltage and current sources are provided using an analog to digital converter driven with digital signals from a microprocessor.

34. The system of claim 33, wherein the digital signals from the microprocessor represent waveforms including sinuisoidal waveforms.