System and method for demand limiting resistive load management

• US 8,014,905 B2
• Filed: 03/07/2007
• Issued: 09/06/2011
• Est. Priority Date: 03/09/2006
• Status: Active Grant

• Current Assignee: Invensys Systems Incorporated (Invensys PLC)
• Original Assignee: Ranco Incorporated of Delaware (Schneider Electric SE)
• Inventors: Ehlers, Gregory A.
• Primary Examiner(s): Decady, Albert
• Assistant Examiner(s): Chang, Sunray
• Application Number:
  US11/683,139
• Publication Number:
  US 20070213880A1
• Time in Patent Office: 1,644 Days
• Field of Search: None
• US Class Current: 700/295
• CPC Class Codes: H02J 13/00002 characterised by monitoring
• CPC Class Codes: H02J 2310/60 Limiting power consumption in the network or in one section of the network, e.g. load shedding or peak shaving
• CPC Class Codes: H02J 3/144 Demand-response operation of the power transmission or distribution network
• CPC Class Codes: Y02B 70/3225 Demand response systems, e.g. load shedding, peak shaving
• 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 10/30 State monitoring, e.g. fault, temperature monitoring, insulator monitoring, corona discharge
• CPC Class Codes: Y04S 20/222 Demand response systems, e.g. load shedding, peak shaving
• CPC Class Codes: Y04S 40/12 characterised by data transport means between the monitoring, controlling or managing units and monitored, controlled or operated electrical equipment

Abstract

An electricity demand limiting system for limiting the electricity consumption of at least one resistive load device. The demand limiting system includes a consumption controller associated with the resistive load device that is operable to infinitely vary the amount of electricity being consumed by the load device. The consumption control device is in operative communication with a load controller such that the load controller can generate a control signal to affect the operation of the consumption control circuit. Preferably, the consumption control circuit is a triac-based circuit that receives the control signal from the load controller and limits the amount of electricity consumed by the resistive load device. The load controller can receive input signals from sensors monitoring the electricity delivery system or from the premise electricity meter. Further, the load controller can receive external inputs from a third party that determine the operation of the load controller in limiting the electricity demands of the resistive load device.

Claims

1. An electricity demand limiting system for limiting the electricity consumption of at least one resistive load device from an electricity delivery system, the demand limiting system comprising:

a consumption control circuit positioned between the electricity delivery system and the resistive load device; and

a load controller in operative communication with the consumption control circuit to provide a control signal to the consumption control circuit such that the consumption control circuit responsively limits the electricity consumption of the resistive load device, while achieving an established demand associated with the resistive load device, based upon the control signal, wherein the load controller is operable to determine at least one of (1) the thermodynamic gain characteristics of the resistive load device and (2) the historical run and recovery time data of the resistive load device, wherein the load controller generates the control signal to operate the consumption control circuit to achieve a desired thermal recovery or temperature as a function of the at least one of (1) the thermodynamic gain characteristics of the resistive load device and (2) the historical run and recovery time data of the resistive load device, where the load controller infinitely regulates the electricity consumption of the resistive load device as a function of a parameter of the control signal, the demand associated with the at least one resistive load including a set point and a predetermined time and the control signal is generated to limit the consumption of electricity by the resistive load and to meet the demand.

2. The demand limiting system of claim 1 wherein the consumption control circuit is a triac-based circuit operable to infinitely regulate the electricity consumption of the resistive load device

3. The demand limiting system of claim 1 wherein the load controller generates the control signal based upon an internal timing device contained within the load controller.

4. The demand limiting system of claim 1 further comprising:

a voltage monitoring device operable to detect the voltage on the electricity delivery system and communicate the detected voltage to the load controller, wherein the control signal is based upon the detected voltage.

5. The demand limiting system of claim 1 further comprising:

a frequency monitoring device operable to detect the frequency of the electricity delivery system and communicate the detected frequency to the load controller, wherein the control signal is based upon the detected frequency.

6. The demand limiting system of claim 1 further comprising:

a premise electricity meter operable to determine the total electricity consumption by a premise including the resistive load device, the premise electricity meter being in communication with the load controller, wherein the load controller generates the control signal to the consumption control circuit based upon the total electricity demand and/or consumption by the premise.

7. The demand limiting system of claim 1 further comprising an input device coupled to the load controller, the input device being operable to receive control parameters from the user, wherein the load controller generates the control signal based upon the control parameters.

8. The demand limiting system of claim 7 wherein the control parameters include demand limits based upon the total cost of electricity consumed.

9. The demand limiting system of claim 1 wherein the consumption control circuit and the load controller are contained within the resistive load device.

10. An electricity demand limiting system, as set forth in claim 1, wherein the at least one resistive load is a water heater, and the thermodynamic gain characteristics includes data related to how quickly the water heater can reheat water at different percentages of its rated capacity.

11. An electricity demand limiting system, as set forth in claim 1, wherein the at least one resistive load is an oven and the thermodynamic gain characteristics includes data related to how quickly the oven can reach a given temperature as a function of percentages of its rated demand.

12. A method of limiting the demand for electricity of at least one resistive load device from an electricity delivery system, the method comprising the steps of:

positioning a consumption control circuit between the electricity delivery system and the resistive load device;

positioning a load controller in communication with the consumption control circuit;

establishing a demand associated with the resistive load device;

determining a need to limit the demand for electricity in the load controller;

determining at least one of (1) the thermodynamic gain characteristics of the resistive load device and/or (2) the historical run and recovery time data of the resistive load device and responsively generating a control signal from the load controller to the consumption control circuit as a function thereof; and

operating the consumption control circuit in response to the control signal to limit the demand for electricity by the resistive load device and to meet the demand associated with the resistive load device while achieving a desired thermal recovery or temperature, where the consumption control circuit infinitely regulates the electricity consumption of the resistive load device as a function of a parameter of the control signal, the demand associated with the at least one resistive load including a set point and a predetermined time and the control signal is generated to limit the consumption of electricity by the resistive load and to meet the demand.

13. The method of claim 12 wherein the consumption control circuit is a triac-based circuit operable to infinitely regulate the electricity consumption of the resistive load device.

14. The method of claim 12 wherein the need to limit the demand for electricity is based upon an internal timing device contained within the load controller.

15. The method of claim 12 further comprising the steps of:

monitoring an electrical characteristic of the electricity delivery system;

determining whether the monitored characteristic varies from a standard parameter; and

generating the control signal from the load controller to the consumption control circuit based upon the difference between the measured characteristic and the standard value.

16. The method of claim 15 wherein the electrical characteristic is the voltage present on the electricity delivery system.

17. The method of claim 15 wherein the electrical characteristic is the frequency of the electricity on the electricity delivery system.

18. The method of claim 12 further comprising the steps of:

monitoring the total electricity demand and or consumption rate of the premise including the resistive load device; and

generating the control signal from the load controller to the consumption control circuit to limit the total electricity demand and/or consumption for the premise.

19. The method of claim 12 further comprising the steps of:

receiving one or more control parameters within the load controller; and

generating a control signal from the load controller based upon the control parameters.

20. A method, as set forth in claim 12, wherein the at least one resistive load is a water heater, and the thermodynamic gain characteristics includes data related to how quickly the water heater can reheat water at different percentages of its rated capacity.

21. A method, as set forth in claim 12, wherein the at least one resistive load is an oven and the thermodynamic gain characteristics includes data related to how quickly the oven can reach a given temperature as a function of percentages of its rated demand.