Method and apparatus for preventing overloads of power distribution networks

• US 20040167732A1
• Filed: 02/26/2004
• Published: 08/26/2004
• Est. Priority Date: 01/02/2002
• Status: Active Grant

• Current Assignee: Schneider Electric IT Corporation (Schneider Electric SE)
• Original Assignee: American Power Conversion Corporation (Schneider Electric SE)
• Inventors: Rasmussen, Neil, Spitaels, James
• Granted Patent: US 7,099,784 B2
• Time in Patent Office: Days
• US Class Current: 702/62
• CPC Class Codes: H02J 2310/40 The network being an on-board power network, i.e. within a vehicle
• CPC Class Codes: H02J 3/14 by switching loads on to, or off from, network, e.g. progressively balanced loading
• 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 70/3225 Demand response systems, e.g. load shedding, peak shaving
• CPC Class Codes: Y04S 20/222 Demand response systems, e.g. load shedding, peak shaving
• CPC Class Codes: Y04S 20/244 the home appliances being or involving heating ventilating and air conditioning [HVAC] units

Abstract

Systems and methods for monitoring power in power distribution systems are provided. In one aspect, a system for monitoring power includes a power monitoring device that measures a value of at least one characteristic of power provided to a branch of a power distribution system. The power monitoring device includes an output that provides the value measured. The system further includes a controller having an input to receive the value measured and an output that couples to a first device powered by the branch to send a maximum power signal to the first device to command the first device to operate at a percentage of maximum power.

Claims

1. A system for monitoring power in a power distribution system, the system comprising:

a power monitoring device located in the power distribution system to measure a value of at least one characteristic of power provided to a branch of the power distribution system, the power monitoring device having an output that provides the value measured; and

a controller having an input to receive the value measured and an output that couples to a first device powered by the branch of the power distribution system to send a power signal to the first device to command the first device to operate at a predetermined percentage of maximum power.

2. The system of claim 1, further comprising a plurality of power monitoring devices, each located in the power distribution system to measure at least one characteristic of power provided to a respective branch of the power distribution system, and each having an output to couple to the controller to provide a value of the characteristic measured.

3. The system of claim 2, wherein each of the respective branches of the power distribution system provides power to at least one respective device, and wherein the controller is adapted to send a power signal to each respective device to command each device to operate at the predetermined percentage of maximum power.

4. The system of claim 3, wherein the controller is adapted to send the power signal to devices powered by one branch at a same time, to cause each of the devices on the one branch to operate at the predetermined percentage of maximum power.

5. The system of claim 4, wherein the controller is adapted to total the values measured for each of a plurality of branch circuits and compare the total with a first overload value to detect an overload condition.

6. The system of claim 5, wherein the controller is adapted to send an alarm signal to an operator upon detection of an overload condition.

7. The system of claim 6, wherein the controller is adapted to send a signal to disconnect power to one or more devices upon detection of an overload condition.

8. The system of claim 7, wherein the at least one characteristic is electrical current.

9. The system of claim 8, wherein the controller has a first network interface to communicate with devices powered by the power distribution system over a first communications network and a second network interface to communicate over a second communications network;

and wherein each of the plurality of power monitoring devices includes a network interface to communicate with the controller over the second communications network.

10. The system of claim 9, wherein the power distribution system includes an uninterruptible power supply, and wherein the controller is adapted to communicate with the uninterruptible power supply to detect that the uninterruptible power supply is operating on battery mode and replace the first overload value with a second overload value.

11. The system of claim 10, wherein the controller is adapted to send a signal to interrupt power to at least one device upon detection that the uninterruptible power supply is operating on battery mode.

12. The system of claim 11, further comprising a plurality of temperature sensors that monitor temperature at locations within a facility, each of the temperature sensors having an output to communicate a temperature value to the controller.

13. The system of claim 12, wherein the controller is adapted to compare temperature values received from the temperature sensors with predetermined values to detect an over temperature error condition, and upon detection of an over temperature error condition sending an alarm signal.

14. The system of claim 13, wherein the controller is adapted to send a signal to interrupt power to at least one device upon detection of an over temperature error condition.

15. The system of claim 1, wherein the controller is adapted to compare the value measured with a predetermined value to detect an overload condition, and the controller is adapted to send a power interrupt signal to interrupt power to the device upon detection of an overload condition.

16. The system of claim 15, wherein the controller is adapted to control at least one device to operate at a reduced power level upon detection of an overload condition.

17. The system of claim 15, wherein the power monitoring device has a plurality of outlets, and the power monitoring device is adapted to send a signal to the controller to indicate a value of the at least one characteristic for each of the plurality of outlets.

18. The system of claim 17, wherein the power monitoring device is adapted to control each of the plurality of outlets, and in response to the power interrupt signal from the controller, the power monitoring device is adapted to interrupt power to at least one of the plurality of outlets.

19. The system of claim 1, wherein the at least one characteristic is electrical current.

20. The system of claim 2, wherein the controller has a first network interface to communicate with devices powered by the power distribution system over a first communications network and a second network interface to communicate over a second communications network;

and wherein each of the plurality of power monitoring devices includes a network interface to communicate with the controller over the second communications network.

21. The system of claim 1, wherein predetermined percentage of maximum power is 100 percent.

22. The system of claim 8, wherein the predetermined percentage of maximum power is 100 percent.

23. A method for monitoring and controlling a power distribution system that has a plurality of circuit branches for providing power to a plurality of devices, the method comprising:

controlling a first device on a first circuit branch to operate at a predetermined percentage of maximum power;

detecting a first value for a characteristic of power provided to the first circuit branch;

controlling a second device on a second circuit branch to operate at a predetermined percentage of maximum power;

detecting a second value for a characteristic of power provided to the second circuit branch;

adding the first value to the second value to obtain a total value;

comparing the total value to an overload value to detect an overload condition;

indicating an alarm condition when the total value exceeds the overload value.

24. The method of claim 23, wherein the first device is controlled to operate at less than the predetermined percentage of maximum power when the second device is controlled to operate at the predetermined percentage of maximum power.

25. The method of claim 24, further comprising controlling one of the plurality of devices to operate in a reduced power mode upon detection of an overload condition.

26. The method of claim 25, further comprising interrupting power to one of the plurality of devices upon detection of an overload condition.

27. The method of claim 26, wherein the characteristic measured is electrical current.

28. The method of claim 27, further comprising:

communicating with the first device and the second device over a first communications network; and

communicating with power detection devices over a second communications network.

29. The method of claim 27, wherein the power distribution system further includes an uninterruptible power supply, and wherein the method further includes steps of:

detecting when the uninterruptible power supply is operating in a battery mode; and

controlling at least one of the plurality of devices to operate in a reduced power mode upon detection of the battery mode.

30. The method of claim 29, further comprising interrupting power to at least one of the plurality of devices upon detection of the battery mode.

31. The method of claim 30, wherein the power distribution system is at least partially contained within a facility, and wherein the method further includes steps of:

measuring air temperature at a plurality of locations within the facility;

comparing at least one value of air temperature measured with a predetermined value to detect an over temperature condition; and

controlling at least one of the plurality of devices to operate in a reduced power mode upon detection of the over temperature condition.

32. The method of claim 31, further comprising interrupting power to at least one of the plurality of devices upon detection of the over temperature condition.

33. The method of claim 26, wherein the power distribution system is at least partially contained within a facility, and wherein the method further includes steps of:

measuring air temperature at a plurality of locations within the facility;

comparing at least one value of air temperature measured with a predetermined value to detect an over temperature condition; and

controlling at least one of the plurality of devices to operate in a reduced power mode upon detection of the over temperature condition.

34. The method of claim 33, further comprising interrupting power to at least one of the plurality of devices upon detection of the over temperature condition.

35. The method of claim 23, wherein the first device and the second device are controlled to simultaneously operate at the predetermined percentage of maximum level, and the method further comprises steps of:

measuring the combined maximum power draw for the first circuit branch and the second circuit branch;

and comparing the measured combined maximum draw with the total overload value.

36. The method of claim 23, wherein the characteristic measured is electrical current.

37. The method of claim 23, further comprising:

communicating with the first device and the second device over a first communications network; and

communicating with power detection devices over a second communications network.

38. The method of claim 23, wherein the predetermined percentage of maximum power is 100 percent.

39. The method of claim 27, wherein the predetermined percentage of maximum power is 100 percent.

48. The system of claim 36, further comprising means for detecting air temperature values in a facility containing the power distribution system.

49. The system of claim 48, further comprising means for comparing the detected air temperature values with predetermined temperature values, and means for interrupting power to at least one of the plurality of devices when the detected air temperature values exceed the predetermined temperature values.

40. A system for monitoring and controlling a power distribution system that has a plurality of circuit branches for providing power to a plurality of devices, the system including:

means for controlling each of the plurality of devices to operate at a predetermined percentage of maximum power;

means for detecting a value of a characteristic of power provided to each of the plurality of circuit branches.

41. The system of claim 40, further comprising means for comparing a total value of the characteristic with a predefined value to detect an overload condition.

42. The system of claim 41, further comprising means for interrupting power to at least one of the plurality of devices when an overload condition is detected.

43. The system of claim 42, wherein the characteristic is electrical current.

44. The system of claim 43, wherein the power distribution system includes at least one uninterruptible power supply, and the system further comprises means for detecting that the uninterruptible power supply is in a battery mode of operation, and means for adjusting the predefined value when the uninterruptible power supply is in the battery mode of operation.

45. The system of claim 44, further comprising means for detecting air temperature values in a facility containing the power distribution system.

46. The system of claim 45, further comprising means for comparing the detected air temperature values with predetermined temperature values, and means for interrupting power to at least one of the plurality of devices when the detected air temperature values exceed the predetermined temperature values.

47. The system of claim 40, wherein the power distribution system includes at least one uninterruptible power supply, and the system further comprises means for detecting that the uninterruptible power supply is in a battery mode of operation, and means for adjusting the predefined value when the uninterruptible power supply is in the battery mode of operation.

50. The system of claim 40, wherein the characteristic is electrical current.

51. The system of claim 40, wherein the predetermined percentage is 100 percent.

52. The system of claim 43, wherein the predetermined percentage is 100 percent.