Power limit and control system

• US 3,894,244 A
• Filed: 10/03/1973
• Issued: 07/08/1975
• Est. Priority Date: 10/03/1973
• Status: Expired due to Term

• Current Assignee: Ross Hill Controls Corp. (NOV, Inc.)
• Original Assignee: Ross K. Hill
• Inventors: Hill, Ross K.
• Primary Examiner(s): Schaefer, Robert K.
• Assistant Examiner(s): Ginsburg, M.
• Application Number:
  US05/403,323
• Time in Patent Office: 643 Days
• Field of Search: 307/11,12,16,31,35,39,86,84,43,38
• US Class Current: 307/16
• 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 new and improved power limit and control system for determining the power output capability of a group of power sources and limiting the power drawn by a number of loads driven by the power sources to the power capabilities of the sources.

Claims

1. A power limit system for limiting the power drawn from a plurality of power sources by a plurality of loads, each of the loads having drive control circuits therewith, to a magnitude within the output capabilities of such sources, comprising:

a. sensor means for sensing the most heavily loaded of the plurality of power sources, said sensor means comprising;

2. sensing the kilowatt output from the sources;

b. comparing the power output of the most heavily loaded of the power sources with a reference power level; and

c. energizing the drive control circuits of the loads to limit the power drawn from the group of power sources to a magnitude within the output capabilities of the power sources when the reference power level is reached.

3. The system of claim 1, wherein said kilowatt sensor means comprises:

means for sensing the largest kilowatt output from the plurality of power sources.

4. The system of claim 1, wherein said sensor means comprises:

means for forming a signal indicating the magnitude of the power output from the most heavily loaded of the plurality of power sources.

5. The system of claim 1, further including:

means for establishing a predetermined reference power level.

6. The system of claim 1, further including:

output indicator means for indicating the output of said comparator means.

7. The system of claim 1, further including:

monitor limit indicator means for indicating when the plurality of loads are drawing power above a power threshold.

8. The system of claim 7, wherein said monitor limit indicator means includes:

switch means for energizing said monitor limit indicator means.

9. The system of claim 8, wherein said monitor limit indicator means further includes:

threshold means for activating said switch means when the power drawn by the plurality of loads exceeds the power threshold.

10. The system of claim 1, further including:

a. first monitor limit indicator means for indicating when the plurality of loads are drawing power above a first threshold level; and

b. second monitor limit indicator means for indicating when the loads are drawing power above a second threshold level.

11. The system of claim 10, wherein:

a. said first monitor limit indicator means includes swItch means for energizing said first monitor limit indicator means; and

b. said second monitor limit indicator means includes switch means for energizing said second monitor limit indicator means.

12. The system of claim 11, wherein:

a. said first monitor limit indicator means includes threshold means for activating said switch means when the power drawn by the plurality of loads exceeds the first power threshold; and

b. said second monitor limit indicator means includes said threshold means for activating said switch means when the power drawn by the plurality of loads exceeds the second power threshold.

13. A method of monitoring the power capability of a group of power sources having drive control circuits and limiting the power drawn from such sources to a magnitude within the capabilities of such sources, comprising the steps of:

a. sensing the most heavily loaded of the power sources, said step of sensing comprising the steps of;

1. sensing the current output from the sources;

2. sensing the kilowatt output from the sources;

b. comparing the power output of the most heavily loaded of the power sources with a reference power level; and

c. energizing the drive control circuits of the loads to limit the power drawn from the group of power sources to a magnitude within the output capabilities of the power sources when the reference power level is reached.

14. The method of claim 13, wherein said steps of sensing comprise the steps of:

a. sensing the largest current output from the sources; and

b. sensing the largest kilowatt output from the sources.