Apparatus and method for monitoring an energy management system

• US 4,855,922 A
• Filed: 03/20/1987
• Issued: 08/08/1989
• Est. Priority Date: 03/20/1987
• Status: Expired due to Term

• Current Assignee: Comverge Incorporated (Itron, Inc.)
• Original Assignee: Scientific-Atlanta Incorporated (Cisco Systems, Inc.)
• Inventors: Rooney, David T., Porter, G. Burns Jr., Huddleston, Paul M.
• Primary Examiner(s): Tarcza, Thomas H.
• Assistant Examiner(s): Issing, Gregory C.
• Application Number:
  US07/028,618
• Time in Patent Office: 872 Days
• Field of Search: 364/492, 364/493, 364/464, 364/551, 364/483, 73/112, 307/35, 307/38, 307/39, 307/29, 340/637, 340/661, 340/687
• US Class Current: 700/295
• 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 3/14 by switching loads on to, or off from, network, e.g. progressively balanced loading
• 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

Abstract

A method and apparatus are provided for monitoring an energy management system which controllably drops load in response to preselected conditions. The apparatus periodically interrupts the energy management system to restore full load. The apparatus monitors energy usage immediately prior to interrupting the energy management system and also monitors the energy usage during interruption when the load is restored. The information gathered at these two times represents the actual energy used when the energy management system is conserving energy, and when the energy management system is disabled and full energy usage is realized. The difference between the two energy usages represents the energy savings realized by using the energy management system.

Claims

1. An apparatus for determining a parameter of operation of an energy management system of the type which controllably drops load from an electrical power network in response to preselected conditions, comprising:

means for periodically interrupting the operation of said energy management system and restoring said load to said network;

means for generating a first energy usage signal representative of energy usage on said network at a time when said energy management is not interrupted by said interrupting means;

means for generating a second energy usage signal representative of energy usage on said network at a time when said interrupting means interrupts said energy management system; and

means responsive to said first energy usage signal and said second energy usage signal for computing said parameter of operation of said energy management system.

2. An apparatus according to claim 1 including a signal conditioning circuit receiving a train of controlled pulses from a utility demand meter indicating electrical energy is being demanded.

3. An apparatus according to claim 1, wherein said computing means comprises a microprocessor, and further comprising means for generating a proper operation signal whenever the microprocessor is operating properly, and a proper operation watchdog means responsive to said proper operation signal for producing a reset signal which resets the microprocessor in response to failure to receive said proper operation signal.

4. An apparatus according to claim 1 including means for automatically printing energy usage and energy savings information on a periodic basis.

5. An apparatus according to claim 1 including means for automatically printing an energy usage and energy savings summary on a monthly basis.

6. An apparatus according to claim 1 including test means for providing immediate information on system operation and energy savings.

7. An apparatus according to claim 1 including means for remotely accessing energy usage and savings information via a telephone modem interface.

8. An apparatus according to claim 7 including means for preventing unauthorized telephone access.

9. An apparatus according to claim 1 including means for determining the peak kilowatt demand for loads connected to said network.

10. An apparatus according to claim 1, including means for determining the peak kilowatt demand for loads connected to said network.

11. An apparatus according to claim 1, wherein said parameter of operation is an energy demand parameter, and further including means responsive to said energy demand parameter for preventing a new peak resultant from loads restored to said network by disabling said interrupting means.

12. An apparatus according to claim 1 including means for establishing a target energy demand level above which said interrupting means does not interrupt the energy management system and restore full load.

13. An apparatus according to claim 12 wherein the target energy demand level is selectively variable within preselected limits.

14. The apparatus of claim 1, wherein said parameter of operation is energy savings realized by use of said energy management system.

15. An apparatus for determining a parameter of operation of an energy management system connected to an electrical power network, comprising:

load control means operatively associated with said energy management system for selectively adding or dropping electrical load from said network in response to a predetermined condition;

interrupting means for controllably interrupting said load control means and for restoring full electrical load, said interrupting means generating a first signal representative of energy usage when said load control means is interrupted and generating a second signal representative of energy usage when said load control means is not interrupted;

computing means responsive to said first and second signals for computing said parameter of operation; and

peak demand control means operatively associated with said energy management system for preventing establishment of a new peak demand level by disabling operation of said interrupting means in response to demand exceeding a preselected peak level.

16. The apparatus of claim 15, wherein said parameter of operation is energy savings realized by use of said energy management system.

17. A method for determining energy saved by an energy management system which controllably drops load from an electrical power network under predetermined conditions, comprising the steps of:

periodically interrupting the energy management system and allowing reconnection of loads to said network;

generating a signal representative of energy usage at a first time when the energy management system is not interrupted;

generating a signal representative of energy usage at a second time when the energy management system is interrupted;

receiving the signals representative of energy usage and determining a difference in energy usage at said first time and said second time; and

applying an energy rate to the difference in order to determine energy saved.

18. A method according to claim 17 wherein the step of periodically interrupting the energy management system includes restoring full load.

19. A method according to claim 18 including determining the peak kilowatt usage.

20. A method according to claim 19 including determining the kilowatt-hours used.

21. A method according to claim 17, further comprising the steps of:

setting a "not to exceed" peak demand level;

monitoring the demand of loads connected to said network;

preventing a new peak demand by not carrying out the interrupting step in response to the monitored demand exceeding the "not to exceed" level.

22. An apparatus for monitoring an energy management system of the type which controllably drops load in response to preselected conditions, comprising:

means for periodically interrupting the energy management system and restoring load;

means for generating a signal representative of energy usage at a time when the energy management system is not interrupted by the interrupting means;

means for generating a signal representative of energy usage at a time when the interrupting means interrupts the energy management system;

means responsive to the signals representing energy usage for computing energy savings; and

means for establishing a target energy demand level above which said interrupting means does not interrupt the energy management system and restore full load.

23. An apparatus according to claim 22 wherein the target energy demand level is selectively variable within preselected limits.