Time of day demand metering system and method

• US 4,199,717 A
• Filed: 02/27/1978
• Issued: 04/22/1980
• Est. Priority Date: 02/27/1978
• Status: Expired due to Term

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Palmer, Ansell W., Germer, Warren R.
• Primary Examiner(s): Rolinec, Rudolph V.
• Assistant Examiner(s): Karlsen, Ernest F.
• Application Number:
  US05/881,503
• Time in Patent Office: 785 Days
• Field of Search: 324/116, 324/103 R, 364/483
• US Class Current: 324/116
• CPC Class Codes: G01R 21/1338 Measuring maximum demand

Abstract

A time of day demand metering system is disclosed for registering the amount of electrical energy consumed during the one demand interval of maximum electrical energy consumption out of a plurality of demand intervals. Means is provided to engage the register of a time of day meter only during those demand intervals when the amount of electrical energy being consumed is in excess of the one previous demand interval of maximum electrical energy consumption.

Claims

1. A time-of-day demand metering system for registering the amount of electrical energy consumed during demand intervals comprising:

(a) selectively engageable means for registering the mount of electrical energy being consumed during said demand intervals;

(b) means for periodically generating electrical pulses having a repetition frequency proportional to the amount of electrical energy being consumed by said time-of-day demand metering system;

(c) means for generating a control signal at prescribed intervals;

(d) means responsive, in a first instance, to said control signal for generating an end of interval signal and responsive, in a second instance, to said control signal and to a comparison signal for generating a demand interval on signal;

(e) means for controlling, during each demand interval, when the registering of the amount of electrical energy being consumed may take place, said means for controlling including,

(1) comparator means for generating said comparison signal,

(2) first and second counter means, each receiving said electrical pulses and each having output terminals connected to said comparator means for providing count signals thereto, said first counter means being set to a predetermined count in response to said end of interval signal and being enabled to count said electrical pulses during each demand interval in the absence of said end of interval signal, said second counter means, in response to said demand interval on signal, being enabled to count said electrical pulses during each demand interval when the contents of said first and second counter means are at least equal as detected by said comparator means generating said comparison signal, whereby the contents of said second counter means manifests a magnitude proportional to the amount of electrical energy consumed in a first demand interval plus that excess amount of electrical energy consumed in each subsequent demand interval in which the amount of electrical energy consumed is greater than the amount consumed in the one previous demand interval of maximum electrical energy consumption; and

(f) means responsive to said demand interval on signal to selectively engage and disengage said means for registering, whereby said means for registering registers the amount of electrical energy consumed during that one demand interval of maximum electrical consumption as controlled by said comparison signal applied to the means for generating said demand interval of signal during said second instance.

2. The time-of-day demand metering system as recited in claim 1, wherein said means for generating said electrical pulses comprises a photo-electric pulse generator for generating said electrical pulses.

3. The time-of-day demand metering system as recited in claim 1 wherein said means responsive to said control signal comprises a demand enable flip flop responsive to said control signal for generating a demand enable signal defining the beginning of a demand interval, a demand flip flop for generating said demand interval on signal, means for setting said demand flip flop to generate said demand interval on signal in response to said comparison signal and the presence of said demand enable signal to effect the engagement of said means for registering, means for applying said end of interval signal to said demand flip flop to effect the resetting thereof, and means responsive to a prescribed number of said control signals for generating said end of interval signal to thereby reset said demand flip flop to cause said demand interval on signal to effect disengagement of said means for registering.

4. The time-of-day demand metering system as recited in claim 3 wherein said system further includes a power source for generating an alternating current signal, with said control signal selectively occuring at a specified point in time to establish a prescribed phase relationship with said alternating current signal to define an on-peak power period of said system and the beginning of a demand interval, said demand enable flip flop receiving said alternating current signal in conjunction with said control signal to set said demand enable flip flop to generate said demand enable signal when said alternating current and control signals are of said prescribed phase relationship, said demand enable flip flop being reset to define an off-peak power period to effect disengagement of said means for registering when said alternating current and control signals are of a second prescribed phase relationship.

5. A time-of-day demand metering system for registering the amount of electrical energy consumed during demand intervals comprising:

(a) selectively engageable means for registering the amount of electrical energy being consumed during said demand intervals;

(b) means for periodically generating electrical pulses having a repetition frequency proportional to the amount of electrical energy being consumed by said time-of-day demand metering system;

(c) means for generating a control signal at prescribed intervals;

(d) means responsive, in a first instance, to said control signal for generating an end of interval signal and responsive, in a second instance, to said control signal and to a comparison signal for generating a demand interval on signal;

(e) means for controlling, during each demand interval, when the registering of the amount of electrical energy being consumed is to take place, said means for controlling including,

(1) comparator means for generating said comparison signal,

(2) first and second counter means, each receiving said electrical pulses and each having output terminals connected to said comparator means for providing count signals thereto, said first counter means being set to a predetermined count in response to said end of interval signal and being enabled to count said electrical pulses during each demand interval in the absence of said end of interval signal, said second counter means, in response to said demand interval on signal, being enabled to count said electrical pulses during each demand interval when the contents of said first and second counter means are at least equal as detected by said comparator means generating said comparison signal, whereby the contents of said second counter means manifests a magnitude proportional to the amount of electrical energy consumed in that one demand interval of maximum electrical energy consumption; and

(f) means responsive to said demand interval on signal to selectively engage and disengage said means for registering, whereby said means for registering registers the amount of electrical energy consumed during that one demand interval of maximum electrical energy consumption as controlled by said comparison signal applied to the means for generating said demand interval on signal during said second instance.

6. A time-of-day demand metering system for registering the amount of electrical energy consumed during demand intervals comprising:

(a) selectively engageable means for registering the amount of electrical energy being consumed during said demand intervals;

(b) means for generating an energy consumption signal representative of the amount of electrical energy being consumed by said time-of-day demand metering system;

(c) means for generating a control signal at prescribed intervals;

(d) means responsive, in a first instance, to said control signal for generating an end of interval signal and responsive, in a second instance, to said control signal and to a comparison signal for generating a demand interval on signal;

(e) means for controlling, during each demand interval, when the registering of the amount of electrical energy being consumed is to take place, said means for controlling including,

(1) comparator means for generating said comparison signal,

(2) first and second means, each receiving said energy consumption signal for accumulatively monitoring the amount of consumed electrical energy and each being connected to said comparator means to provide corresponding values to said comparator means proportional to the amount of consumed electrical energy, said first means being set to a prescribed value in response to said end of interval signal and being enabled to monitor said energy consumption signal to respondingly change its value in the absence of said end of interval signal, said second means, in response to said demand interval on signal, being enabled to monitor said energy consumption signal during each demand interval when the magnitudes of the values of said first and second means are at least equal as detected by said comparator means generating said comparison signal, whereby the value of said second means manifests a magnitude proportional to the amount of electrical energy consumed in that one demand interval of maximum electrical energy consumption; and

(f) means responsive to said demand interval on signal to selectively engage and disengage said means for registering whereby said means for registering registers the amount of electrical energy consumed during that one demand interval of maximum electrical energy consumption as controlled by said comparison signal applied to the means for generating said demand interval on signal during said second instance.

7. A time-of-day demand metering system for registering the amount of electrical energy consumed during preselected demand intervals comprising:

(a) selectively engageable means for registering the amount of electrical energy being consumed during said demand intervals;

(b) means for periodically generating electrical pulses having a repetition frequency proportional to the amount of electrical energy being consumed by said time-of-day demand metering system;

(c) means for generating a control signal at prescribed intervals defining on and off peak power periods;

(d) on/off peak detector means responsive, in a first instance, to said control signal defining an off-peak power period for generating an off-peak signal and responsive, in a second instance, to said control signal defining an on-peak power period and to a comparison signal for generating a demand interval on signal, said on/off peak detector means further responsive, in a third instance, to an end of interval signal defining the end of a demand interval to effect the generation of said off-peak signal;

(e) interval counter means responsive, in said third instance, to said control signal during an on-peak power period for providing said end of interval signal to said on/off peak detector means to effect the generation of said off-peak signal;

(f) demand interval means for controlling, during each demand interval, when the registering of the amount of electrical energy being consumed is to take place, said demand interval means including,

(1) comparator means for generating said comparison signal,

(2) first and second counter means, each receiving said electrical pulses and each having output terminals connected to said comparator means for providing count signals thereto, said first counter means receiving said off-peak signal and responding thereto to remain in a reset state during the presence of said off-peak signal and being enabled to count said electrical pulses in the absence of said off-peak signal, said second counter means, in response to said demand interval on signal, being enabled to count said electrical pulses during each demand interval when the contents of said first and second counter means are at least equal as detected by said comparator means generating said comparison signal, whereby the contents of said second counter means manifests a magnitude proportional to the amount of electrical energy consumed in that one demand interval of maximum electrical consumption; and

(g) means responsive to said demand interval on signal to selectively engage and disengage said means for registering in accordance with said end of interval signal applied to said on/off peak detector means, whereby said means for registering registers the amount of electrical energy consumed during that one demand interval of maximum electrical energy consumption.

8. In a power system of the alternating current type, a time of day demand meter for registering the amount of electrical energy consumed by the system during preselected demand intervals comprising:

(a) selectively engageable means for registering the amount of electrical energy being consumed during said demand intervals;

(b) means for generating electrical pulses having a repetition frequency proportional to the amount of electrical energy being consumed by said power system;

(c) means for generating a control signal at prescribed intervals which is either in or out of phase with the system alternating current during said prescribed intervals;

(d) interval counter means responsive to said control signal for generating an end of interval signal defining the end of a demand interval after counting a prescribed number of said control signals;

(e) an on/off peak detector including,

(1) first detector means capable of achieving first and second states, said first detector means responsive to said control signal and the system alternating current to achieve said first and second states in accordance with the in and out of phase relationships respectively between said control signal and the system alternating current, said first detector means generating a demand enable signal representative of on and off-peak power period when in said first and second states respectively,

(2) second detector means capable of achieving first and second states for generating a demand interval signal in accordance with the states thereof, said second detector means including means for setting said second detector means to said first state during an on-peak power period in response to said demand enable signal and a comparison signal, and generating an off-peak signal to set said second detector means to said second state during an off-peak power period in response to said demand enable signal, or during an on-peak power period in response to said end of interval signal;

(f) demand interval means for controlling, during each demand interval, when the registering of the amount of electrical energy being consumed is to take place, said demand interval means including,

(1) comparator means for generating said comparison signal,

(2) first and second counter means, each receiving said electrical pulses and each having output terminals connected to said comparator means for providing count signals thereto, said first counter means being held in a reset state by said off-peak signal and enabled to count said electrical pulses in the absence of said off-peak signal, said second counter means, in response to said demand interval signal, being enabled to count said electrical pulses during each demand interval of an on-peak power period when the contents of said first and second counter means are at least equal as detected by said comparator means generating said comparison signal, whereby the contents of said second counter means manifests a magnitude proportional to the amount of electrical energy consumed in that one demand interval of maximum electrical energy consumption; and

(g) means responsive to said demand interval signal for selectively engaging and disengaging said means for registering in accordance with said end of interval signal applied to said second detector means whereby said means for registering registers the amount of electrical energy consumed during that one demand interval of maximum electrical energy consumption.

9. In a time-of-day demand metering system, a method of registering the amount of electrical energy consumed during demand intervals comprising the steps of:

(a) continuously generating a series of pulses having a repetition frequency proportional to the amount of electrical energy being consumed by said time-of-day demand metering system;

(b) providing first and second counters capable of counting said pulses;

(c) continuously comparing the contents of said first and second counters;

(d) presetting said first counter to be prescribed count before a first demand interval;

(e) initiating a demand interval of a specified length of time during which the consumption of electrical energy may be registered;

(f) applying said pulses to said first counter in all demand intervals while selectively applying said pulses to said second counter during the periods of those demand intervals in which the amount of electrical energy being consumed is in excess of the one previous demand interval of maximum electrical energy consumption when the contents of said counters are at least equal;

(g) registering the amount of electrical energy being consumed during the period in each of those demand intervals when there is at least equality in the contents of said first and second counters;

(h) terminating the present demand interval while presetting said first counter to said prescribed count to inhibit the registering of electrical energy and any further counting of said pulses by said counters whereby the amount of electrical energy registered represents the amount of electrical energy consumed in the one previous demand interval of maximum electrical energy consumption; and

(i) repeating steps (e) through (h) for a second demand interval.

10. A time-of-day demand metering system for registering the amount of electrical energy consumed during demand intervals comprising:

(a) selectively engageable means for registering the amount of electrical energy being consumed during said demand intervals;

(b) means for generating electrical pulses having a repetition frequency proportional to the amount of electrical energy being consumed by said time-of-day demand metering system;

(c) means for generating a control signal a prescribed intervals;

(d) means responsive, in a first instance, to said control signal for generating an end of interval signal and responsive, in a second instance, to said control signal and to a comparison signal for generating a demand interval on signal;

(e) means for controlling, during each demand interval, when the registering of the amount of electrical energy being consumed is to take place, said means for controlling including,

(1) comparator means for generating said comparison signal,

(2) first and second counter means, each receiving said electrical pulses and each having output terminals connected to said comparator means for providing count signals thereto, said first counter means being reset to zero in response to said end of interval signal and being enabled to count said electrical pulses during each demand interval in the absence of said end of interval signal, said second counter means, in response to said demand interval on signal, being enabled to count said electrical pulses during each demand interval when the contents of said first and second counter means are at least equal as detected by said comparator means generating said comparison signal, whereby the contents of said second counter means manifests a magnitude proportional to the amount of electrical energy consumed in a first demand interval plus that excess amount of electrical energy consumed in each subsequent demand interval in which the amount of electrical energy consumed is greater than the amount consumed in the one previous demand interval of maximum electrical energy consumption;

(f) means responsive to said demand interval on signal to selectively engage and disengage said means for registering, whereby, said means for registering registers the amount of electrical energy consumed during that one demand interval of maximum electrical energy consumption; and

(g) reset switch means actuable to reset said first and second counter means to initialize said time-of-day demand metering system.

11. A three rate structured time-of-day demand metering system for registering the total amount of electrical energy consumed and the amount of electrical energy consumed during on-peak power periods and preselected demand intervals, comprising:

(a) a total register for continuously registering the amount of electrical energy being consumed by the system;

(b) an on-peak register engageable to register the amount of electrical energy consumed during said on-peak power periods;

(c) a demand register engageable to register the amount of electrical energy being consumed during said demand intervals;

(d) a programmable control circuit for generating a control signal at prescribed intervals to engage and disengage said on-peak register during on and off peak power periods respectively, and during demand intervals in which the amount of electrical energy consumed is to be measured;

(e) means for generating electrical pulses having a repetition frequency proportional to the amount of electrical energy being consumed by the system;

(f) on/off peak detector means responsive, in a first instance, to said control signal defining an off-peak power period for generating an off-peak signal and responsive, in a second instance, to said control signal defining an on-peak power period and to a comparison signal for generating a demand interval on signal;

(g) interval counter means responsive, in a third instance, to said control signal during an on-peak power period for generating an end of interval signal defining the end of a demand interval, said end of interval signal being provided to said on-off peak detector means to effect the generation of said off-peak signal;

(h) demand interval means for controlling, during each demand interval, when the registering of the amount of electrical energy being consumed is to take place, said demand interval means including,

(1) comparator means for generating said comparison signal,

(2) first and second counter means, each receiving said electrical pulses and each having output terminals connected to said comparator means for providing count signals thereto, said first counter means receiving said off-peak signal and responding thereto to remain in a reset state during the presence of said off-peak signal and being enabled to count said electrical pulses in the absence of said off-peak signal, said second counter means, in response to said demand interval on signal, being enabled to count said electrical pulses during each demand interval when the contents of said first and second counter means are at least equal as detected by said comparator means generating said comparison signal, whereby the contents of said second counter means manifests a magnitude proportional to the amount of electrical energy consumed in the one demand interval of maximum electrical energy consumption; and

(i) means responsive to said demand interval on signal to selectively engage and disengage said demand register in accordance with said end of interval signal applied to said on/off peak detector means, whereby said demand register registers the amount of electrical energy consumed during that one demand interval of maximum electrical energy of consumption.

12. The three rate structured time-of-day demand metering system as recited in claim 11, further including reset switch means actuable to reset said first and second counter means to initialize said system.

13. In a time-of-day demand metering system, a method of registering the amount of electrical energy consumed during demand intervals comprising the steps of:

(a) continuously generating an electrical signal representative of the amount of electrical energy being consumed by said time-of-day demand metering system;

(b) providing from first and second means, first and second values respectively capable of being changed by said electrical signal applied to said first and second means during said demand intervals, said first value having a magnitude proportional to the amount of electrical energy being consumed during each demand interval, and said second value, at the termination of each demand interval, having a magnitude proportional to the amount of electrical energy consumed during the one previous demand interval of maximum electrical energy consumption;

(c) continuously comparing the magnitudes of said first and second values;

(d) presetting said first value to a prescribed magnitude before a first demand interval;

(e) initiating a demand interval of a specified length of time during which the consumption of electrical energy may be registered;

(f) during each demand interval, applying said electrical signal to said first means to change the magnitude of said first value, while selectively applying said electrical signal to said second means to update the magnitude of said second value during the period of those demand intervals in which the amount of electrical energy being consumed is in excess of the one previous demand interval of maximum electrical energy consumption when the magnitudes of said first and second values are at least equal;

(g) registering the amount of electrical energy being consumed during the period in each of those demand intervals when there is at least equality in the magnitudes of said first and second values;

(h) terminating the present demand interval while presetting said first value to said prescribed magnitude to inhibit the registering of electrical energy and any further changing of said first and second values by said electrical signal, whereby the amount of electrical energy registered represents the amount of electrical energy consumed in the one previous demand interval of maximum electrical energy consumption; and

(i) repeating steps (e) through (h) for a second demand interval.