Determination of ohmic losses in electrical devices

1. A method for determining voltage loss in an electrical device, the method comprising:

obtaining an array A of voltage values corresponding to at least one current interrupt measurement at current I n , wherein I n corresponds to current values I 1 , I 2 , . . . , I n , wherein subscript n is at least 3;

forming an array D of difference values using a difference of said array A over an elapsed time;

processing the difference values of the array D to obtain V n , by a processing unit;

determining V n for each I n to form an array V of V n ; and

calculating a resistance, R, using the array V, thereby determining voltage loss in the electrical device.

2. The method of claim 1 , wherein the difference values of the array D are formed according to the formula: D(j)=A(j)−A(j−1), wherein j is an index for the elapsed time.

3. The method of claim 2 , wherein the processing comprises:

computing the standard deviation of the difference values of the array D;

identifying each index, j′, of the array D having a difference value greater than 8 standard deviations from the median of the distribution of the difference values of the array D;

determining a range of indices, j*, consisting of the largest contiguous band of indices j′ in the array D; and

forming a difference between the arithmetic mean of the voltage values under the current I n and the maximum voltage value of array A in the index range j*.

4. The method of claim 1 , wherein the calculating comprises performing a linear least-squares fit of V n versus I n .

5. The method of claim 1 , further comprising:

adjusting a polarization curve for ohmic losses using the resistance R by forming a sum of each measured voltage, V m , and the product of each measured current, I m , and the resistance, R.

6. A method for determining voltage loss in an electrical device, the method comprising:

obtaining an array A of voltage values corresponding a current interrupt measurement at current I n , wherein I n corresponds to current values I 1 , . . . , I n , wherein subscript n is at least 3;

forming an array D of difference values using a difference of said array A over an elapsed time, wherein the difference values of the array D are formed according to the formula: D(j)=A(j)−A(j−1), wherein j is an index for the elapsed time;

computing the standard deviation of the difference values of the array D, by a processing unit;

identifying each index, j′, of the array D having a difference value greater than 8 standard deviations from the median of the distribution of the difference values of the array D;

determining a range of indices, j*, consisting of the largest contiguous band of indices j′ in the array D;

forming a difference between the arithmetic mean of the voltage values under the current I n , and the maximum voltage value of array A in the index range j*, to obtain V n ;

determining V n for each I n to form an array V of V n ; and

calculating a resistance, R, by performing a linear least-squares fit of V n versus I n , thereby determining the voltage loss in the electrical device.

7. A device for determining voltage loss in an electrical device, comprising:

input means for receiving voltage values;

a processor configured to determine voltage losses in an electrical device, performing instructions comprising:

obtaining an array A of voltage values corresponding to at least one current interrupt measurement at current I n , wherein I n corresponds to current values I 1 , . . . , I n , wherein subscript n is at least 3;

forming an array D of difference values using a difference of said array A over an elapsed time;

processing the voltage values of the array D to obtain V n ;

determining V n for each I n to form an array V of V n ;

calculating a resistance, R, using the array V; and

output means generating a signal.

8. The device of claim 7 , wherein the input means is selected from the group consisting of a coaxial cable and an ethernet cable.

9. The device of claim 7 , wherein the difference values of the array D are formed according to the formula: D(j)=A(j)−A(j−1), wherein j is an index for the elapsed time.

10. The device of claim 9 , wherein the processing comprises:

computing the standard deviation of the difference values of the array D;

identifying each index, j′, of the array D having a difference value greater than 8 standard deviations from the median of the distribution of the difference values of the array D;

determining a range of indices, j*, consisting of the largest contiguous band of indices j′ in the array D; and

forming a difference between the arithmetic mean of the voltage values under the current I n and the maximum voltage value of array A in the index range j*.

11. The device of claim 7 , wherein the calculating comprises performing a linear least-squares fit of V n versus I n .

12. The device of claim 7 , further comprising:

adjusting a polarization curve for ohmic losses using the resistance R by forming a sum of each measured voltage, V m , and the product of each measured current, I m , and the resistance, R.

13. The device of claim 7 , wherein the output means is selected from the group consisting of a computer, a printer, a signal and a screen.

14. A computer program product stored on a computer readable medium, when executed by a processor, for causing a computer to determine voltage loss in an electrical device, performing instructions comprising

obtaining an array A of voltage values corresponding to at least one current interrupt measurement at current I n , wherein I n corresponds to current values I 1 , . . . , I n , wherein subscript n is at least 3;

forming an array D of difference values using a difference of said array A over an elapsed time;

processing the voltage values of the array D to obtain V n ;

determining V n for each I n to form an array V of V n ; and

calculating a resistance, R, using the array V.

15. The computer program of claim 14 , wherein the difference values of the array D are formed according to the formula: D(j)=A(j)−A(j−1), wherein j is an index for the elapsed time.

16. The computer program of claim 15 , wherein the processing comprises:

computing the standard deviation of the difference values of the array D;

identifying each index, j′, of the array D having a difference value greater than 8 standard deviations from the median of the distribution of the difference values of the array D;

determining a range of indices, j*, consisting of the largest contiguous band of indices j′ in the array D; and

forming a difference between the arithmetic mean of the voltage values under the current I n and the maximum voltage value of array A in the index range j*.

17. The computer program of claim 14 , wherein the calculating comprises performing a linear least-squares fit of V n versus I n .

18. The computer program of claim 14 , further comprising:

adjusting a polarization curve for ohmic losses using the resistance R by forming a sum of each measured voltage, V m , and the product of each measured current, I m , and the resistance, R.