Method for determining electrical energy consumption

• US 5,229,713 A
• Filed: 04/25/1991
• Issued: 07/20/1993
• Est. Priority Date: 04/25/1991
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Bullock, Donald F., Hardy, Samuel G.
• Primary Examiner(s): Karlsen, Ernest F.
• Application Number:
  US07/691,252
• Time in Patent Office: 817 Days
• Field of Search: 324/142, 324/141, 324/103 R, 324/107, 364/483
• US Class Current: 324/142
• CPC Class Codes: G01R 21/1331 Measuring real or reactive component, measuring apparent energy

Abstract

A method of operating a meter to perform the steps of generating a measure of real energy consumed, generating a measure of reactive energy consumed, and generating, from the real energy and reactive energy measures, a measure of apparent energy consumed. In one embodiment, the real energy and reactive energy measures are provided as integer quantity inputs. Particularly, assume S=kVAh, P=kWh, Q=kVARh, and R=Residue. Respective registers store values of P, [2P+1], Q, [2Q+1], and the sum [P² +Q² ]. Initially, the P, Q, and [P² +Q² ] registers are set to zero, while the [2P+1] and [2Q+1] registers are initialized to 1. At the arrival of a P pulse, the value in the [2P +1] register is added to the [P² +Q² ] register, then the P register is incremented by 1 and the [2P+1] register is incremented by 2. Exactly the same steps are carried out subsequent to receipt of a Q pulse. A set of registers also is used to store the S and [2S+1] data, and generation of the S pulses is determined as follows. After arrival of either a P or Q pulse, a trial subtraction of [2S+1] is made from the [P² +Q² ] register. If the subtraction does not cause an underflow, an S pulse is generated, the S register is incremented by 1, and the [2S+1] register is incremented by 2. If the subtraction causes an underflow, the [P² +Q² ] register is reset to its previous value, the other registers are not incremented, and no S pulse is generated.

Claims

1. A method of operating a meter coupled between an end user and a power delivery system, the meter comprising metering means and processing means, the processing means comprising register means for storing values of P, (2P-1), Q (2Q-1), R, S and (2S-1) where P=real energy, Q=reactive energy, S=apparent energy and R=remainder, said method comprising the steps of:

outputting, from the metering means, and upon each occurrence of the end user consuming a predetermined quantum of real energy , a pulse representative of the predetermined quantum of real energy, which pulse is provided to the processing means, and upon receipt of each real energy pulse by the processing means, controlling the processing means to perform the steps of;

incrementing the (2P-1) register means by two;

adding the value of the (2P-1) register means to the R register means; and

incrementing the P register means by one;

outputting, from the metering means, and upon each occurrence of the end user consuming a predetermined quantum of reactive energy, a pulse representative of the predetermined quantum of reactive energy, which pulse is provided to the processing means, and upon receipt of each reactive energy pulse by the processing means, controlling the processing means to perform the steps of;

incrementing the (2Q-1) register means by two;

adding the value of the (2Q-1) register means to the R register means; and

incrementing the Q register means by one;

generating, in the processing means, and from values stored in the register means, a measure of apparent energy.

2. A method in accordance with claim 1 wherein the P, Q, R and S registers are initially set to zero and the (2P-1), (2Q-1) and (2S-1) registers are initially set to negative 1.

3. A method in accordance with claim 1 wherein when the value of the S register means reaches a predetermined value, the values then in the respective register means are stored and then the P, Q, R, S, (2P-1), (2Q-1) and (2S-1) register means are reset.

4. A method in accordance with claim 3 further comprising register means for storing values equal to 2R and (4S+1) and upon resetting the P, Q, R, S, (2P-1), (2Q-1) and (2S-1) register means, said method further comprises the steps of:

adding the current value of 2R to the 2R register means;

subtracting (4S+1) from the total stored in the 2R register means; and

if the subtraction results in a positive number, incrementing the S register by one.

5. A method in accordance with claim 3 further comprising lookup table means having S and R values for the expression [(S² +R)^1/2 -S] stored therein and wherein upon resetting the register means, the current value of R is used to locate the associated predetermined fraction for S stored in the lookup table means and the fraction is then stored in a predesignated register for determining whether the S register should be incremented.

6. A method in accordance with claim 1 further comprising the step of:

determining power factor from the values stored in at least two of the register means.

7. A method in accordance with claim 1 wherein generation of a measure of apparent energy comprises the steps of:

subtracting the value of the (2S-1) register means from the value of the R register means, and if the subtraction results in a positive number, then performing the steps of;

incrementing the (2S-1) register means by two;

decrementing the R register means by (2S-1); and

incrementing the S register means by one.

8. Apparatus for determining apparent energy consumed by an end user coupled to a power delivery system providing such energy to the end user, said apparatus comprising:

metering means for coupling between the end user and the power delivery system, said metering means being configured to generate, each time a predetermined quantum of real and reactive energy has been consumed from the power delivery system by the end user, a real energy pulse representative of the predetermined quantum of real energy consumed by the end user and a reactive energy pulse representative of the predetermined quantum of reactive energy consumed by the end user, respectively;

processing means coupled to said metering means for receiving the real energy pulses and the reactive energy pulses output therefrom, said processing means further comprising register means for storing values of P, (2P-1) Q, (2Q-1), R, S and (2S-1) where P=real energy, Q=reactive energy, S=apparent energy and R=remainder, said processing means being controlled to perform the steps of;

upon receipt of a real energy pulse from said metering means, performing the steps of;

incrementing said (2P-1) register means by two;

adding the value of said (2P-1) register means to said R register means; and

incrementing said P register means by one;

upon receipt of the reactive energy pulse from said metering means, performing the steps of;

incrementing said (2Q-1) register means by two;

adding the value of said (2Q-1) register means to said R register means; and

incrementing said Q register means by one;

generating, from values stored in said register means, a measure of apparent energy.

9. Apparatus in accordance with claim 8 wherein said P, Q, R and S register means are initially set to zero and said (2P-1), (2Q-1) and (2S-1) register means are initially set to negative one.

10. Apparatus in accordance with claim 8 further comprising means for resetting said register means when the value of S reaches a predetermined value and means for determining whether to increment said S register mean by one upon resetting said register means.

11. Apparatus in accordance with claim 8 further comprising:

means for determining power factor.

12. A method of operating a meter coupled between an end user and a power delivery system, the meter comprising metering means and processing means, the processing means comprising register means for storing values of W, Q, S, R, (2Q+1), (2W+1) and (2S+1), where W=watthours, Q=Qhours, S=apparent energy and R=remainder, said method comprising the steps of:

outputting, from the metering means, and upon each occurrence of the end user consuming a predetermined quantum of real energy, a pulse representative of the predetermined quantum of real energy, which pulse is provided to the processing means, and upon receipt of each real energy pulse by the processing means, controlling the processing means to perform the steps of;

adding 4*(2W-1) to the R register means;

subtracting (4*Q) from the R register means;

incrementing the W register means by one; and

incrementing the (2W+1) register means by two;

outputting, from the metering means, and upon each occurrence of the end user consuming a predetermined quantum of Q energy, a pulse representative of the predetermined quantum of Q energy, which pulse is provided to the processing means, and upon receipt of each Q energy pulse by the processing means, controlling the processing means to perform the steps of;

adding 4*(2 Q+1) to the R register means;

subtracting (4*W) from the R register means;

incrementing the Q register means by one; and

incrementing the (2Q+1) register means by two;

generating, in the processing means, and from values stored in the register means, a measure of apparent energy.

13. A method in accordance with claim 12 wherein the real energy and the Qhour energy measures are integer quantities.

14. A method in accordance with claim 12 wherein the real, Qhour, and apparent energy are related by:

space="preserve" listing-type="equation">R=[4Q.sup.2 -4QW-3S.sup.2 ],

where;

S=apparent energy;

R=residue;

W=real energy; and

Q=standard "Qh" at 60 degrees lag angle.

15. A method in accordance with claim 12 wherein the W, Q, S and R register means are initialized to zero and the (2Q+1) , (2W+1) and (2S+1) register means are initialized to one.

16. A method in accordance with claim 15 wherein upon receipt of a W pulse, the following steps are performed:

adding 4*(2W+1) to the R register means;

subtracting (4*Q) from the R register means;

incrementing the W register means by one; and

incrementing the (2Q+1) register means by two; and

checking for an S output pulse.

17. A method in accordance with claim 15 wherein generating a measure of apparent energy comprises the steps of:

comparing 3*(2S-1) to the value of the R register means;

if 3*(2S-1) is greater than the value stored in the R register means, doing nothing and waiting for another input pulse from metering means;

if 3*(2S-1) is less than or equal to the value stored in the R register means, then subtracting 3*(2S+1) from the R register means, incrementing the S register by one, incrementing the (2S+1) register means by two, and outputting an S output pulse.

18. A method in accordance with claim 15 wherein the value in the R register means is used as an index in a look-up table to determine whether the remainder requires that a make-up pulse be generated.

19. A method in accordance with claim 15 wherein the values of W and Q are utilized as indices to a look-up table in which values of power factor are stored.

20. A method of operating a meter coupled between an end user and a power delivery system, the meter comprising metering means and processing means, the processing means comprising register means for storing values of W, Q, S, R, (2Q-1), (2W-1) and (2S-1), where W=watthours, Q=Qhours, S=apparent energy and R=remainder, said method comprising the steps of:

outputting, from the metering means, and upon each occurrence of the end user consuming a predetermined quantum of real energy, a pulse representative of the predetermined quantum of real energy, which pulse is provided to the processing means, and upon receipt of each real energy pulse by the processing means, controlling the processing means to perform the steps of;

incrementing the W register means by one;

incrementing the (2W-1) register means by two;

adding 4*(2W-1) to the R register means; and

subtracting (4*Q) from the R register means;

outputting, from the metering means, and upon each occurrence of the end user consuming a predetermined quantum of Q energy, a pulse representative of the predetermined quantum of Q energy, which pulse is provided to the processing means, and upon receipt of each Q energy pulse by the processing means, controlling the processing means to perform the steps of;

incrementing the Q register means by one;

incrementing the (2Q-1) register means by two;

adding 4*(2Q-1) to the R register means; and

subtracting (4*W) from the R register means.

21. A method in accordance with claim 20 wherein the W, Q, S and R register means are initialized to zero and the (2Q-1), (2W-1) and (2S-1) register means are initialized to negative one.

22. A method in accordance with claim 21 wherein generating a measure of apparent energy comprises the steps of:

(a) incrementing the S register means by one;

(b) incrementing the [2S-1] register means by two;

(c) subsequent of generation of a W or Q pulse, subtracting three times the value of the [2S-1] register means from the value of the R register means;

(d) if the subtraction in step (c) does not cause an underflow, then;

(i) generating an S pulse;

(e) if the subtraction in step (c) causes an underflow, then;

(i) resetting the R register means to its previous value;

(ii) resetting the S register means to its previous value;

(iii) resetting the [2S-1] register means to its previous value; and

(iv) not generating an S pulse.

23. A method in accordance with claim 20 wherein the value in the R register means is used as an index in a look-up table to determine whether the remainder requires that a make-up pulse be generated.

24. A method in accordance with claim 20 wherein the values of W and Q are utilized as indices to a look-up table in which values of power factor are stored.

25. A method of operating a meter coupled between an end user and a power delivery system, the meter comprising meting means and processing means, the processing means comprising register means for storing values of P, (2P+1), (2Q+1), R, S and (2S+1) where P=real energy, Q=reactive energy, S=apparent energy and R=remainder, said method comprising the steps of:

outputting, from the metering means, and upon each occurrence of the end user consuming a predetermined quantum of real energy, a pulse representative of the predetermined quantum of real energy, which pulse is provided to the processing means, and upon receipt of each real energy pulse by the processing means, controlling the processing means to perform the steps of;

adding the value of the (2P+1) register means to the R register means;

incrementing the P register means by one; and

incrementing the (2P-1) register means by two;

outputting, from the metering means, and upon each occurrence of the end user consuming a predetermined quantum of reactive energy, a pulse representative of the predetermined quantum of reactive energy, which pulse is provided to the processing means, and upon receipt of each reactive energy pulse by the processing means, controlling the processing means to perform the steps of;

adding the value of the (2Q+1) register means to the R register means;

incrementing the Q register means by one;

incrementing the (2Q-1) register means by two; and

generating, in the processing means, and from values stored in the register means, a measure of apparent energy, generation of the measure of apparent energy comprising the steps of;

subtracting the value of the (2S-1) register means from the value of the R register means, and if the subtraction results in a positive number, then performing the steps of;

decrementing the R register means by (2S+1);

incrementing the S register means by one; and

incrementing the (2S+1) register means by two.

26. A method in accordance with claim 25 wherein the P, Q, R and S registers are initially set to zero and the (2P+1), (2Q+1) and (2S+1) registers are initially set to positive 1.

27. A method in accordance with claim 25 wherein when the value of the S register means reaches a predetermined value, the values then in the respective register means are stored and then the P, Q, R, S, (2P+1), (2Q+1) and (2S+1) register means are reset.

28. A method in accordance with claim 27 further comprising register means for storing values equal to 2R and (4S+1), and upon resetting the P, Q, R, S, (2P+1), (2Q+1) and (2S+1) register means, said method further comprises the steps of:

adding the current value of 2R to the 2R register means;

subtracting (4S+1) from the total stored in the 2R register means; and

if the subtraction results in a positive number, incrementing the S register by one.

29. A method in accordance with claim 27 further comprising lookup table means having S and R values for the expression [(S² +R)^1/2 -S] stored therein and wherein upon resetting the register means, the current value of R is used to locate the associated predetermined fraction for S stored in the lookup table means and the fraction is then stored in a predesignated register for determining whether the S register should be incremented.

30. A method in accordance with claim 25 further comprising the step of:

determining power factor from the values stored in at least two of the register means.

31. Apparatus for determining apparent energy consumed by an end user coupled to a power delivery system providing such energy to the end user, said apparatus comprising:

metering means for coupling between the end user and the power delivery system, said metering means being configured to generate, each time a predetermined quantum of real and reactive energy has been consumed from the power delivery system by the end user, a real energy pulse representative of the predetermined quantum of real energy consumed by the end user and a reactive energy pulse representative of the predetermined quantum of reactive energy consumed by the end user, respectively;

processing means coupled to said metering means for receiving the real energy pulses and the reactive energy pulses output therefrom, said processing means further comprising register means for storing values of P, (2P+1), Q, (2Q+1), R, S and (2S+1) where P=real energy, Q=reactive energy, S=apparent energy and R=remainder, said processing means being controlled to perform the steps of;

upon receipt of a real energy pulse from said metering means, performing the steps of;

adding the value of said (2P+1) register means to said R register means;

incrementing said P register by one; and

incrementing said (2P+1) register means by two;

upon receipt of the reactive energy pulse from said metering means, performing the steps of;

adding the value of said (2Q+1) register means to said R register means;

incrementing said Q register by one; and

incrementing said (2Q+1) register means by two;

generating, from values stored in said register means, a measure of apparent energy, generation of the measure of apparent energy comprising the steps of;

subtracting the value of the (2S-1) register means from the value of the R register means, and if the subtraction results in a positive number, then performing the steps of;

decrementing the R register means by (2S+1);

incrementing the S register means by one; and

incrementing the (2S+1) register means by two.

32. Apparatus in accordance with claim 31 wherein said P, Q, R and S register means are initially set to zero and said (2P+1), (2Q+1) and (2S+1) register means are initially set to positive one.

33. Apparatus in accordance with claim 31 further comprising means for determining whether to increment said S register means by one upon resetting said register means.

34. Apparatus in accordance with claim 31 further comprising means for determining power factor.