Remote control circuit breaker system with on-off-tripped-problem status storage and indication

• US 4,556,882 A
• Filed: 11/15/1982
• Issued: 12/03/1985
• Est. Priority Date: 11/15/1982
• Status: Expired due to Term

• Current Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.)
• Original Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.)
• Inventors: Schmerda, Richard F., Chacon, M. Frank, Smith, Frank E., Brifman, Josef
• Primary Examiner(s): YUSKO, DONALD
• Application Number:
  US06/441,973
• Time in Patent Office: 1,114 Days
• Field of Search: 340/825.06, 340/825.07, 340/825.16, 340/825.17, 340/825.37, 340/639, 340/638, 340/825.18
• US Class Current: 340/3.44
• CPC Class Codes: H01H 9/167 Circuits for remote indication
• CPC Class Codes: H02J 13/00009 using pulsed signals
• CPC Class Codes: H02J 13/00034 the elements or equipment being or involving an electric power substation
• CPC Class Codes: H02J 13/00036 the elements or equipment being or involving switches, relays or circuit breakers circuits for indication of single switches H01H9/167
• 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: Y02E 60/00 Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y04S 40/121 using the power network as support for the transmission

Abstract

A remote control circuit breaker and contactor system having at least one I/O circuit functioning as an interface between a central processing unit and a plurality of up to 32 devices such as remote circuit breakers for each I/O circuit, each remote circuit breaker having an individual electronic circuit which receives commands from the I/O circuit to turn the breaker or contactor on or off or hold and also senses the state of the breaker contacts and the control line and upon request sends back status codes which are stored in the memory in the I/O circuit to be read when desired by the central processing unit. Four-state status information is provided including open, closed, tripped and problem (low voltage, open or shorted control line). Contact state is determined by directly measuring the contact resistance in single break contacts (or solid state device contactors) or the contact voltage in double-break contacts. The I/O circuit provides noise rejection using measured noise as a threshold to minimize the effect of electrical noise on the status communication signals coming from the remote breaker electronic circuit. In the event electrical noise on the control line or the like causes rapid turn-on and turn-off of the remote breaker, a rapid cycle inhibit circuit for a timed interval stops such cycling of the remote breaker after a predetermined number thereof to prevent damage to the remote device due to overheating. The remote breaker electronic circuit affords manual control of the breakers or contactors and trip indication of the breakers in addition to computer control through the I/O circuit. The system uses tri-state communication circuitry which includes a hold command and prevents unwanted state changes during losses of power or when a control line shorts to ground or opens.

Claims

1. A remote control circuit breaker system comprising:

a plurality of remote control circuit breakers, each having contacts for controlling connection of power from an electric power supply source over a power line to a respective load;

an electronic control unit for each said circuit breaker;

a local I/O circuit arranged to communicate with said plurality of remote control circuit breakers'"'"' electronic control units;

control lines comprising conductor pair connections between said I/O circuit and respective ones of said remote breaker'"'"'s electronic control units over which said communication is conducted;

a central processing unit arranged to communicate with said I/O circuit so as to transmit close and open commands for said breakers thereto and to read therefrom status data that is stored therein;

means in said I/O circuit for transmitting said close and open commands over said control lines to the respective electronic control units;

four-state sensing means in each said electronic control unit for sensing the closed, open or tripped status of the associated breaker contacts and a problem status of said power line or said control line and means for generating data respectively indicative thereof;

means including said sensing means in each said electronic control unit for applying a close or open operate signal to the respective breaker in response to said commands whenever the command coming over the corresponding control line differs from the sensed closed or open status of the respective breaker contacts;

means in said I/O circuit for periodically transmitting status information request pulses over said control lines to the respective electronic control units in sequence;

means in each said electronic control unit responsive to the respective information request pulse for tripping its data generating means into operation and to transmit said four-state status indicative data back to said I/O circuit;

and means in said I/O circuit for receiving and storing said four-state status indicative data so as to make it available for reading by said central processing unit.

2. The remote control circuit breaker system claimed in claim 1, wherein:

said central processing unit is arranged for tri-state communication with said I/O circuit so as to transmit hold command signals for said breakers thereto in addition to said close and open commands;

means in said I/O circuit for receiving a hold command signal from said central processing unit and applying said hold command signals to all said electronic control units;

and means in each said electronic control unit responsive to the respective hold command signal for keeping the respective breaker in its current state until said hold command signal is removed.

3. The remote control circuit breaker system claimed in claim 1, wherein:

said four-state sensing means and said data generating means comprise;

means for performing a high frequency resistance measurement of single-break contacts and for providing error free first data if said contacts are open or second data if said contacts are closed regardless of configuration or self generation characteristics of load.

4. The remote control circuit breaker system claimed in claim 3, wherein:

said four-state sensing means and said data generating means comprise;

a closed position memory;

means for setting said memory responsive to sensing closed contacts and for resetting said memory in response to said open command;

and means responsive to sensing open contacts while said closed position memory is in its set state for providing third data indicative of a contacts tripped open state.

5. The remote control circuit breaker system claimed in claim 1, wherein:

said four-state sensing means and said data generating means comprise;

means for performing a voltage measurement of double-break contacts and for providing error free first data if said contacts are open or second data if said contacts are closed regardless of configuration or self generation characteristics of load.

6. The remote control circuit breaker system claimed in claim 5, wherein:

said four-state sensing means and said data generating means comprise;

a closed position memory;

means for setting said memory responsive to sensing closed contacts and for resetting said memory in response to said open commands;

and means responsive to sensing open contacts while said closed position memory is in its set state for providing third data indicative of a contacts tripped open state.

7. The remote control circuit breaker system claimed in claim 4, wherein:

said four-state sensing means and said data generating means comprises;

means responsive to sensing of no power line voltage on said breaker contacts for providing fourth data indicative of said problem status.

8. The remote control circuit breaker system claimed in claim 4, wherein:

said data generating means comprises;

means responsive to an open or shorted condition of said control line for providing said fourth data indicative of said problem state.

9. The remote control circuit breaker system claimed in claim 1, wherein:

said means in each said electronic control unit for applying a close or open signal comprises;

rapid cycle inhibit means responsive to alternate application of said close and open signals above a predetermined rapid cyclic frequency due to electrical noise on the control line or other cause for stopping and inhibiting the same for a predetermined time interval long enough to prevent overheating damage to said breakers.

10. The remote control circuit breaker system claimed in claim 1, wherein:

said means in said I/O circuit for receiving and storing said four-state status indicative data comprises;

sample and hold means comprising;

means for measuring the electrical noise level coming in on the control line during a predetermined first portion of said information request pulse and providing a noise level signal proportional thereto;

threshold means for comparing said status indicative data with said noise level signal and for transmitting status indicative data that differs from said noise level signal by a predetermined amount thereby effectively to distinguish said data from said noise level signal;

and means for storing said data.

11. The remote control circuit breaker system claimed in claim 1, wherein:

each said electronic control unit comprises means for selectively setting the same for alternative manual control and status indication of the breaker contacts;

a manual indicator-control unit for each said breaker operable to control the corresponding electronic control unit to apply said close or open signal to said breaker;

and means in said electronic control unit responsive to tripping of said breaker for transmitting a trip command to said manual indicator-control unit to set it in an indicator state to visually indicate the tripped condition of the breaker.

12. The remote control circuit breaker system claimed in claim 1, wherein:

said means including said sensing means in each said electronic control unit for applying a close or open operate signal to the respective breaker in response to said commands whenever the command coming over the corresponding control line differs from the sensed closed or open status of the respective breaker contacts comprises;

a breaker energization control timer;

means responsive to said command for triggering said timer to time the length of said operate signal sufficient to insure operation of the breaker;

and means responsive to said sensing means sensing that the breaker contact state agrees with the command for terminating said operate signal.

13. The remote control circuit breaker system claimed in claim 12, wherein:

said breaker energization control timer comprises;

means for timing the length of said breaker operate signal as an inverse function of the magnitude of the line voltage so as to apply the breaker operate closed or open longer when the line voltage is low than when it is high thereby to insure change of state of the breaker.

14. The remote control circuit breaker system claimed in claim 1, wherein:

said means including said sensing means in each said electronic control unit for applying a close or open operate signal to the respective breaker in response to said commands whenever the command coming over the corresponding control line differs from the sensed closed or open status of the respective breaker contacts also comprises;

means for terminating said operate signal after a predetermined time interval long enough to insure transfer of the breaker contacts in most cases;

a time-delay responsive repeat circuit for causing reapplication of said operate signal a predetermined time interval after initiation of operation thereof;

and means responsive to failure of said sensed closed or open contact status to agree with said command for said predetermined time interval for initiating and maintaining operation of said time-delay responsive repeat circuit to cause said reapplication of said operate signal.

15. The remote control circuit breaker system claimed in claim 12, wherein:

said means including said sensing means in each said electronic control unit for applying a close or open operate signal to the respective breaker in response to said commands whenever the command coming over the corresponding control line differs from the sensed closed or open status of the respective breaker contacts also comprises;

a time-delay responsive repeat circuit for measuring a predetermined time interval;

and means responsive to failure of said sensed closed or open contact status to agree with said command for said predetermined time interval for operating said time delay responsive repeat circuit;

and means responsive to said repeat circuit at the end of said predetermined time interval for triggering said energization control timer to apply and time the length of another corresponding operate signal.

16. The remote control circuit breaker system claimed in claim 1, wherein:

said remote control circuit breaker system also comprises;

means for sensing an overload current condition on said power line for providing an overload signal;

and means responsive to said overload signal for applying said open operate signal to the respective breaker.

17. The remote control circuit breaker system claimed in claim 16, wherein:

said means including said sensing means in each said electronic control unit for applying a close or open operate signal to the respective breaker in response to said commands comprises;

a time-delay responsive repeat circuit for causing reapplication of said operate signal a time interval after initiation of operation thereof;

and means responsive to mismatch of said sensed contact status with said overload caused open operate signal for said time interval for operating said repeat circuit to cause said reapplication of said open operate signal.

18. The remote control circuit breaker system claimed in claim 1, wherein:

said means in said I/O circuit for transmitting said close and open commands over said control lines to the respective electronic control units comprises;

means using tri-state communication so as to transmit said commands as positive and negative voltages so that a shorted or grounded fault will not cause an error in breaker state.

19. The remote control circuit breaker system claimed in claim 11, wherein:

said electronic control unit comprises;

means responsive to receipt of a command from said manual indicator control unit for applying said close or open operate signal to the respective breaker;

means for terminating said operate signal after a time interval long enough to insure transfer of the breaker contacts in most cases;

and a timed delay repeat circuit responsive to failure of said sensed closed or open contact status to agree with said command for causing reapplication of said operate signal.

20. The remote control circuit breaker system claimed in claim 19, wherein:

said electronic control unit further comprises;

means responsive to said sensing means and said command transmitting means when the sensed closed or open contact state matches said command for terminating said operate signal to the respective breaker before the end of said time interval.

21. The remote control circuit breaker system claimed in claim 11, wherein:

said electronic control unit further comprises;

means for tripping said breaker in response to overload;

means for sensing an overload current condition on said power line for providing an overload signal;

and means responsive to said overload signal for applying said open signal to the breaker;

means normally responsive to said open signal for changing said tripped status to open status indication;

means responsive to said sensing means sensing a tripped status for transmitting a trip command to said manual indicator-control unit to trip the same open;

and hold-off means responsive to said trip command for delaying said changing of status indication until said manual indicator control unit has actually tripped open.

23. The remote control circuit breaker system claimed in claim 20, wherein:

said power switching means is a single break switch;

and said sensing means comprises means for sensing the resistance of said single-break switch.

24. The remote control circuit breaker system claimed in claim 20, wherein:

said power switching means is a double-break switch;

and said sensing means comprises means for sensing voltage at said double-break switch.

25. The remote control circuit breaker system claimed in claim 21, wherein:

said electric power supply source is a D.C. source.

22. A remote control circuit breaker system comprising:

a plurality of remote control circuit breakers, each having power switching means for controlling connection of power from an electric power supply source over a power line to a respective load and tripping means responsive to overload;

an electronic control unit for each said circuit breaker;

a local circuit arranged to communicate with said plurality of remote control circuit breakers'"'"' electronic control units;

control lines comprising conductor pair connections between said local circuit and respective ones of said electronic control units over which two-way communication is conducted;

means in said local circuit for transmitting close and open commands over said control lines to the respective electronic control units;

means in each said electronic control unit coupled to the respective breaker power switching means for sensing their open, closed or tripped state and means for generating serial status codes respectively indicative thereof;

means in each said electronic control unit responsive to said close and open commands for applying corresponding close and open operate signals to the respective remote control circuit breakers;

and means in said local circuit for causing said electronic control units to transmit said status codes to it and for storing the same.

26. The remote control circuit breaker system claimed in claim 22, wherein:

said electric power supply source is an A.C. source.

27. A remote control load switching system comprising:

a plurality of remote control switching devices, each having power switching means for controlling connection of power from an electric power supply source over a power line to a respective load;

an electronic control unit for each said switching device;

a local circuit arranged to communicate with said plurality of remote control switching devices'"'"' electronic control units;

control lines comprising conductor pair connections between said local circuit and respective ones of said electronic control units over which two-way communication is conducted;

means in said local circuit for transmitting tri-state close, open and hold command signals over said control lines to the respective electronic control units;

means in each said electronic control unit coupled to the respective device'"'"'s power switching means for sensing their open or closed state and means for generating serial status codes respectively indicative thereof;

means in each said electronic control unit responsive to said close and open command signals for applying corresponding close and open operate signals to the respective remote control switching devices;

and means in said local circuit for causing said electronic control units to transmit said serial status codes to it and for parallel storing the same.

28. A remote control load switching system comprising:

a plurality of remote control switching devices, each comprising power switching means for controlling connection of power from an electric power supply source over a power line to a respective load;

a local circuit arranged to communicate with said plurality of remote control switching devices;

control lines comprising conductor pair connections between said local circuit and respective ones of said remote control switching devices over which two-way communication is conducted;

means in said local circuit for transmitting continuous close, open or hold command signals over said control lines to the respective remote control switching devices;

means for sensing the open or closed state of said power switching means of the respective switching devices in sequence and means for generating status codes respectively indicative thereof;

means responsive to said close and open command signals for applying corresponding close and open operate signals to the respective remote control switching devices whenever a closed or open command signal differs from said sensed closed or open state;

and means for interrupting said command signals to store said status codes.

29. A remote control load switching system comprising:

a plurality of remote control switching devices, each comprising power switching means for controlling connection of power from an electric power supply source over a power line to a respective load;

a local circuit arranged to communicate with said plurality of remote control switching devices;

control lines comprising conductor pair connections between said local circuit and respective ones of said remote control switching devices over which two-way communication is conducted;

means for transmitting continuous close and open command signals over said control lines to the respective remote control switching devices;

means for sensing the open, closed and tripping status of said power switching means of said remote control switching devices and a problem status of said system and means for generating status codes respectively indicative thereof;

means responsive to said close and open command signals for applying corresponding close and open operate signals to the respective remote control switching devices if a closed or open command signal differs from said sensed closed or open or tripped state;

and means for interrupting said command signals for storing said status codes.

30. The remote control load switching system claimed in claim 29, wherein said means for transmitting close and open command signals over said control lines to the respective remote control switching devices comprises:

a plurality of command latches, one for each of said control lines;

a central processing unit for setting said command latches to selective close and open command states whereby their outputs provide corresponding continuous close and open command signals;

and means for transmitting said continuous close and open command signals over said control lines to the respective remote control switching devices.

31. The remote control load switching system claimed in claim 30, wherein said means for interrupting said command signals for storing said status code comprises:

a memory;

means for multiplexing said control lines for predetermined time intervals long enough to receive said status codes and to store them in corresponding multiplexed locations in said memory.

means responsive to said multiplexing of said control lines for interrupting the respective command signals for said time intervals;

a display;

and means in said central processing unit for reading the status of selected remote control switching devices and displaying the same on said display.