Switchgear and relaying configuration

• US 20040036461A1
• Filed: 08/22/2002
• Published: 02/26/2004
• Est. Priority Date: 08/22/2002
• Status: Abandoned Application

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Sutherland, Peter Edward
• Application Number:
  US10/225,955
• Publication Number:
  US 20040036461A1
• Time in Patent Office: Days
• US Class Current: 323/355
• CPC Class Codes: G01R 15/18 using inductive devices, e.g. transformers
• CPC Class Codes: H01F 38/20 Instruments transformers
• CPC Class Codes: H01F 38/28 Current transformers
• 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 71/125 characterised by sensing elements, e.g. current transformers for differential protection H01H83/144
• CPC Class Codes: H02H 3/006 Calibration or setting of parameters
• 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

A method for operating an electrical apparatus includes mounting an instrument transformer proximate a load current carrying conductor, wherein the instrument transformer includes a current transformer for supplying an analog input signal proportional to a load current, the current transformer is coupled to a relay front-end module that includes a current-to-voltage converter circuit and is configured to couple to a remote protection module, converting the analog input signal to a digital input signal, transmitting the digital input signal to the remote protection module; and activating contacts to operate the electrical apparatus based on the digital input signals.

Claims

1. A method for operating an electrical apparatus, said method comprising:

mounting an instrument transformer proximate a load current carrying conductor, the instrument transformer includes a current transformer for supplying an analog input signal proportional to a load current, the current transformer coupled to a relay front-end module that includes a current-to-voltage converter circuit and is configured to couple to a remote protection module;

converting the analog input signal to a digital input signal;

transmitting the digital input signal to the remote protection module; and

activating contacts to operate the electrical apparatus based on the digital input signals.

2. A method in accordance with claim 1 wherein mounting an instrument transformer comprises mounting a current transformer including an integrally formed relay front-end module proximate a load current carrying conductor.

3. A method in accordance with claim 1 wherein processing the digital input signal further comprises receiving predetermined limit values from the user interface module.

4. A method in accordance with claim 3 wherein receiving predetermined limit values comprises a breaker protection coordination scheme.

5. A method in accordance with claim 3 wherein processing the digital input signal further comprises receiving protection module calibration data.

6. An instrument transformer comprising a current transformer for supplying an analog input signal proportional to a load current, said current transformer coupled to a relay front-end module, said relay front-end module comprising a current-to-voltage converter circuit, said relay front-end module configured to couple to a remote protection module.

7. An instrument transformer in accordance with claim 6 wherein said relay front-end module further comprises an analog-to-digital (A/D) converter coupled to said current-to-voltage converter circuit.

8. An instrument transformer in accordance with claim 6 wherein said relay front-end module further comprises a step down transformer electrically coupled to a plurality of relay front-end module input terminations extending from said relay front-end module for receiving the analog input signal from said current transformer.

9. An instrument transformer in accordance with claim 7 wherein said front-end module further comprises a fiber optic interface coupled to said A/D converter.

10. An instrument transformer in accordance with claim 6 wherein said relay front-end module further comprises a fiber optic power supply coupled to said current-to-voltage converter and an A/D converter.

11. An instrument transformer in accordance with claim 10 wherein said fiber optic power supply is coupled to a remote fiber optic power supply module.

12. An instrument transformer in accordance with claim 6 wherein said protection module is coupled to a user interface module.

13. An instrument transformer in accordance with claim 6 wherein said user interface module comprises a data display.

14. An instrument transformer in accordance with claim 6 wherein said user interface module comprises a communications port.

15. An instrument transformer in accordance with claim 6 wherein said user interface module comprises an integral keypad.

16. An instrument transformer in accordance with claim 6 wherein said current transformer and relay front-end module are integrally formed.

17. An electrical apparatus for connecting a load to an electrical power source, said apparatus comprising:

separable contacts selectively connecting the load to the power source when closed and disconnecting the load from the power source when open; and

an instrument transformer comprising a current transformer for supplying an input signal proportional to a load current, said current transformer coupled to a relay front-end module, said relay front-end module comprising a current-to-voltage converter circuit, said relay front-end module configured to couple to a remote protection module.

18. An electrical apparatus in accordance with claim 17 wherein said relay front-end module further comprises an analog-to-digital (A/D) converter coupled to said current-to-voltage converter circuit.

19. An electrical apparatus in accordance with claim 17 wherein said relay front-end module further comprises a step down transformer electrically coupled to a plurality of relay front-end module input terminations extending from said relay front-end module for receiving the analog input signal from said current transformer.

20. An electrical apparatus in accordance with claim 18 wherein said relay front-end module further comprises a fiber optic interface coupled to said A/D converter.

21. An electrical apparatus in accordance with claim 17 wherein said relay front-end module further comprises a fiber optic power supply coupled to said current-to-voltage converter and an A/D converter.

22. An electrical apparatus in accordance with claim 21 wherein said fiber optic power supply is coupled to a remote fiber optic power supply module.

23. An electrical apparatus in accordance with claim 17 wherein said protection module is coupled to a user interface module.

24. An instrument transformer in accordance with claim 23 wherein said user interface module comprises a data display.

25. An instrument transformer in accordance with claim 23 wherein said user interface module comprises a communications port.

26. An instrument transformer in accordance with claim 23 wherein said user interface module comprises an integral keypad.

27. An electrical apparatus in accordance with claim 17 wherein said current transformer and relay front-end module are integrally formed.