Electric utility demand limiting device and method

• US 4,390,876 A
• Filed: 07/25/1980
• Issued: 06/28/1983
• Est. Priority Date: 07/25/1980
• Status: Expired due to Term

• Current Assignee: Southern California Edison Company (Edison International)
• Original Assignee: Southern California Edison Company (Edison International)
• Inventors: Phillips, Charles E., Bjorklund, Glenn J.
• Primary Examiner(s): Yusko, Donald J.
• Application Number:
  US06/172,251
• Time in Patent Office: 1,068 Days
• Field of Search: 340/147 R, 340/825.17, 340/310 A, 340/825.06, 364/492, 307/39, 307/35
• US Class Current: 340/3.7
• CPC Class Codes: G01R 21/00 Arrangements for measuring electric power or power factor G01R7/12 takes precedence
• CPC Class Codes: G01R 21/1333 adapted for special tariff measuring

Abstract

An electric utility demand limiting device and method for disconnecting and reconnecting a load, such as a residential customer load, from a utility company power system. The device may include a preset demand limit against which power consumption is compared when the device is remotely enabled in response to a remote control signal from the utility company. The demand limit may be variable.

Claims

1. An electrical power demand limiting device for controllably disconnecting a local load extraneous the device from a power source comprising

signal generating means for generating a first signal representative of the electrical power consumption of the load,

comparing means responsive to the signal generating means for comparing the first signal to a preset electrical power consumption limit,

receiving means for receiving a remote control signal from a power production source responsive to conditions at said power production source for providing an enable output in response thereto to enable the operation of the device,

disconnecting means responsive to the comparing means and to the enable output of the receiving means for disconnecting the said extraneous local load entirely from the power source when the first signal exceeds the preset limit and when the receiving means has enabled the device, and

resetting means for resetting the disconnecting means to reconnect the local load to the power source such reconnected load being the entire initial load or a locally selected portion of said initial load.

4. A device as in claim 1 wherein said preset limit is adjustable.

6. A device as in claim 1 wherein said receiving means is further responsive to a second remote control signal for terminating said enable output.

7. A device as in claim 1 wherein said resetting means is operated manually or when the enable output is not present from said receiving means.

2. An electrical power demand limiting device for controllably disconnecting a local load extraneous the device from a power source comprising

signal generating means for generating a first signal representative of the electrical power consumption of the load,

comparing means responsive to the signal generating means for comparing the first signal to a preset electrical power consumption limit,

receiving means for receiving a remote control signal a power production source responsive to conditions at said power production source for providing an enable output in response thereto to enable the operation of the device,

disconnecting means responsive to the comparing means and to the enable output of the receiving means for disconnecting the said extraneous local load entirely from the power source when the first signal exceeds the preset limit and when the receiving means has enabled the device wherein said disconnecting means further includes timing means for disconnecting the entire load from the power source after the first signal has exceeded the preset limit for a predetermined period, and

resetting means for resetting the disconnecting means to reconnect the local load to the power source such reconnected load being the entire initial load or a locally selected portion of said initial load.

3. A device as in claim 2 wherein said timing means is further responsive to the enable output of the receiving means for disconnecting the entire load from the power source when the first signal has exceeded the preset limit and the enable output from the receiving means are concurrently present for said predetermined length of time.

5. An electrical power demand limiting device for controllably disconnecting a local load extraneous the device from a power source comprising

signal generating means for generating a first signal representative of the electrical power consumption of the load,

comparing means responsive to the signal generating means for comparing the first signal to a preset electrical power consumption limit,

receiving means for receiving a remote control signal from a power production source responsive to conditions at said power production source for providing an enable output in response thereto to enable the operation of the device, said receiving means includes timing means for providing the enable output for a predetermined period of time in response to the remote control signal,

disconnecting means responsive to the comparing means and to the enable output of the receiving means for disconnecting the said extraneous local load entirely from the power source when the first signal exceeds the preset limit and when the receiving means has enabled the device, and

resetting means for resetting the disconnecting means to reconnect the local load to the power source such reconnected load being the entire initial load or a locally selected portion of said initial load.

8. An electrical power demand limiting device for controllably disconnecting a local extraneous the device load from a power source comprising

signal generating means for generating a first signal representative of the electrical power consumption of the load,

comparing means responsive to the signal generating means for comparing the first signal to an adjustable preset electrical power consumption limit,

receiving means for receiving a remote control signal from a power production source responsive to conditions at said power production source for providing an enable output in response thereto to enable the operation of the device,

disconnecting means responsive to the signal generating means and to the receiving means for disconnecting the said extraneous local load entirely from the power source when the first signal exceeds the preset limit and the receiving means has enabled the device, said disconnecting means including timing means for disconnecting the entire load from the power source after the first signal has continuously exceeded the preset limit for a predetermined period of time, and

resetting means for resetting the disconnecting means to reconnect the local load to the power source, said resetting means being operated manually or when the enable output is not present from the receiving means, and such reconnected load being the entire initial load or a locally selected portion of said portion of said initial load.

9. A device as in claim 8 further including alarm means for providing an alarm signal when the first signal exceeds the preset limit and said enable output is present.

10. A device as in claim 9 further including means for providing a second alarm signal when said first signal exceeds the preset limit for a second predetermined period of time, said second predetermined period of time being less than said first predetermined period of time.

11. A device as in claim 8 wherein said device further includes alarm means for providing an alarm when said enable output is present.

12. A device as in claim 8 wherein said disconnecting means includes bistable switch means including solenoid means for performing said disconnecting and reconnecting of the load and the power production source.

13. An electrical power demand limiting device adapted for installation at a utility customer site for controllably disconnecting the utility customer from a utility power service comprising

signal generating means for generating a first signal representative of the electrical power consumption of the utility customer,

comparing means responsive to the signal generating means for comparing the first signal to a preset electrical power consumption limit, said preset limit being adjustable by the utility company,

receiving means for providing an enable output to enable the operation of the device and for terminating the enable output, at least said enable output being provided in response to a control signal from the utility company,

disconnecting means responsive to the comparing means and to the receiving means for disconnecting the load from the utility power service when the first signal exceeds the preset limit and the enable output is present, said disconnecting means including timing means for delaying said disconnection until at least the first signal has exceeded the preset limit for a predetermined length of time,

reset means operable at the utility customer site for generating a reset signal,

means responsive to the reset signal and responsive to the receiving means for resetting the disconnecting means when either the reset signal is present or the enable output is not present to reconnect the utility customer to the utility power service to thereby restore the utility power service to the utility customer, and

said device being housed in a housing having an adaptor including first connector means for plugging into a utility meter socket and second connector means for receiving a utility meter and said disconnecting means includes switch means for connecting or disconnecting said first connector means and said second connector means.

14. A device as in claim 13 wherein said switch means is a bistable switch.

15. A device as in claim 13 wherein said predetermined length of time is reset when the first signal is less than the preset limit.

16. A method for controllably limiting power demand from a power source by a local extraneous load including the steps of

generating remotely a first signal at a power production source responsive to conditions at said power production source to enable the power demand limiting,

generating a second signal representative of electrical power consumption by the load,

comparing the electrical power consumption to a preset electrical power consumption limit,

receiving the first signal from said power production source and providing an enable output in response thereto,

disconnecting the said extraneous local load entirely from the power source when the electrical power consumption exceeds the consumption limit and the enable output is present, and

reconnecting the local load to the power source in response to reset means or when the enable output is no longer present, such reconnected load being the entire initial load or a locally selected portion of said initial load.

18. A method as in claim 16 further including the step of

providing an alarm when the electrical power consumption exceeds the preset limit.

17. A method for controllably limiting power demand from a power source by a local extraneous load including the steps of

generating remotely a first signal at a power production source responsive to conditions at said power production source to enable the power demand limiting,

generating a second signal representative of electrical power consumption by the load,

comparing the electrical power consumption to a preset electrical power consumption limit,

receiving the first signal from said power production source and providing an enable output in response thereto,

disconnecting the said extraneous local load entirely from the power source when the electrical power consumption exceeds the consumption limit and the enable output is present, wherein the disconnecting step further includes delaying disconnecting the load from the power source until the electrical power consumption has exceeded the preset limit for a continuous predetermined time period, and

reconnecting the local load to the power source in response to reset means or when the enable output is no longer present, such reconnected load being the entire initial load or a locally selected portion of said initial load.

19. A method for controllably limiting power demand from a utility power source at a utility customer site including the steps of

generating a first signal remotely at said utility power source to enable the power demand limiting,

generating a second signal representative of electrical power consumption at the utility customer site,

comparing the electrical power consumption to an adjustable preset electrical power consumption limit,

receiving the first signal from said utility power source and providing an enable output in response thereto,

disconnecting the utility customer site from the utility power source when the electric power consumption exceeds the consumption limit and the enable output is present, said disconnecting being delayed until the electrical power consumption has exceeded the preset limit for a continuous predetermined time period, and

reconnecting the utility customer site to the utility power source in response to reset means operated at the utility customer site or when the enable output is no longer present.

20. A method as in claim 19 wherein said disconnecting step further includes applying a third signal to a bistable switch means for disconnecting the utility customer site from the utility power source and applying a fourth signal to the bistable switch means for reconnecting the utility customer site to the utility power source.

21. A method for controllably limiting the power demand from a utility power source at a utility customer site including the steps of

generating a first signal remotely at said utility power source to enable the power demand limiting,

generating a second signal representative of electrical power consumption at the utility customer site,

comparing the electrical power consumption to an adjustable preset electrical power consumption limit,

receiving the first signal from said utility power source and providing an enable output in response thereto,

applying a third signal to bistable switch means to disconnect the utility customer site from the utility power source when the electrical power consumption exceeds the consumption limit and the enable output is present, said disconnecting being delayed until the electrical power consumption has continuously exceeded the preset limit for a predetermined time period, and

applying a fourth signal to the bistable switch means to reconnect the utility customer site to the utility power source in response to reset means operated at the utility customer site or when the enable output is no longer present.

22. An electrical power demand limiting device adapted for installation at a utility customer site for controllably limiting power demand from a utility power source comprising

signal generating means for generating a first signal representative of the electrical power consumption of the utility customer,

comparing means responsive to the signal generating means for comparing the first signal to a preset electrical power consumption limit, said preset limit being adjustable by the utility source,

receiving means for providing an enable output to enable the operation of the device and for terminating the enable output, at least said enable output being provided in response to a control signal from the utility source,

disconnecting means responsive to the comparing means and to the receiving means adapted for disconnecting load from the utility power source when the first signal exceeds the preset limit and the enable output is present, said disconnecting means including timing means for delaying said disconnection until at least the first signal has exceeded the preset limit for a predetermined length of time,

reset means operable at the utility customer site for generating a reset signal,

means responsive to the reset signal and responsive to the receiving means for resetting the disconnecting means when either the reset signal is present or the enable output is not present to reconnect the utility customer to the utility power source to thereby restore utility power to the utility customer, and

said device being housed in a housing having an adapter including first connector means for plugging into a utility meter socket and second connector means for receiving a utility meter.

23. An adapter as claimed in claim 22 wherein said disconnecting means is connected with switch means and is adapted to activate said switch means.

24. An adapter as claimed in either claim 22 or claim 23 wherein said housing includes a substantially cylindrical horizontal meter extender, and a substantially rectangular casing mounting on a support column between the extender and casing.

25. A method for controllably limiting power demand from a utility power source at a utility customer site including the steps of plugging into a meter utility socket an adapter for receiving a meter at the end remote from the socket,

generating a first signal representative of the electrical power consumption of the utility customer,

generating a second signal remotely from said power utility source to enable the power demand limiting,

comparing the first signal to a preset electrical power consumption limit, said preset limit being adjustable by the utility company,

receiving the second signal and providing an enable output in response to the second signal from the utility company,

disconnecting load from the utility power service when the first signal exceeds the preset limit and the enable output is present, said disconnecting being delayed until at least the first signal has exceeded the preset limit for a predetermined length of time,

generating a reset signal at the utility customer site, and

reconnecting load when either the reset signal is present or the enable output is not present thereby to reconnect the utility customer to the utility power source and restore utility power to the utility customer.

26. A method as claimed in claim 25 wherein disconnection includes applying a third signal to switch means for disconnecting the utility customer site from the utility power.