System and method for fault detection in an electrical device

1. A method comprising:

selecting a measured parameter from a sensor coupled to a subsurface electrical device;

obtaining a plurality of samples for the measured parameter;

removing at least one invalid sample from the plurality of samples of the measured parameter to generate a remaining number of samples, wherein the at least one invalid sample is based on a predefined sample criteria;

computing a diagnostic parameter based on the remaining number of samples from the plurality of samples, if the remaining number of samples is greater than a predefined threshold number, otherwise terminating the method;

obtaining a rule from a plurality of rules stored in a database, based on the diagnostic parameter, wherein the rule is indicative of a standard operating condition of the subsurface electrical device;

evaluating whether the computed diagnostic parameter satisfies the obtained rule, to generate an output; and

determining a measured operating condition of the subsurface electrical device based on the output.

2. The method of claim 1 , wherein the predefined sample criteria comprises a parameter range and not-a-number criteria.

3. The method of claim 1 , wherein the measured parameter comprises a plurality of measured parameters comprising vibration, supply current, intake pressure, supply voltage, and leakage current.

4. The method of claim 3 , wherein the computed diagnostic parameter comprises a plurality of diagnostic parameters comprising an amplitude, a difference value, a mean, a median, a variance, a log likelihood ratio, a slope value, and a coefficient of determination, of each measured parameter from the plurality of measured parameters.

5. The method of claim 4 , wherein the standard and measured operating conditions of the subsurface electrical device, comprises a plurality of operating conditions comprising an excessive vibration, an emulsion pattern, a broken shaft fault, a motor insulation damage, and a pump failure.

6. The method of claim 5 , wherein the rule for determining the excessive vibration comprises:

a comparative statement to verify if the amplitude of the vibration is less than a first amplitude threshold; and

a comparative statement to verify if the amplitude of the vibration is greater than a second amplitude threshold.

7. The method of claim 5 , wherein the rule for determining the emulsion pattern comprises:

a comparative statement to verify if the supply current is greater than a current threshold;

a comparative statement to verify if the variance of the supply current is greater than a current variance threshold; and

a comparative statement to verify if the variance of the intake pressure is greater than a pressure variance threshold.

8. The method of claim 5 , wherein the rule for determining the broken shaft fault comprises:

a comparative statement to verify if the supply current is greater than a current threshold;

a comparative statement to verify if the log likelihood ratio is greater than a likelihood threshold; and

a comparative statement to verify if the difference value is less than a difference threshold.

9. The method of claim 5 , wherein the rule for determining the motor insulation damage comprises:

a comparative statement to verify if a difference between two successive sample values of the leakage current is less than a leakage current threshold;

a comparative statement to verify if the leakage current is a non-zero value; and

a comparative statement to verify if a difference between a first median of one set of sample values of the leakage current and a second median of another set of sample values of the leakage current is greater than a median threshold.

10. The method of claim 5 , wherein the rule for determining the pump failure comprises:

a comparative statement to verify if the supply current is greater than a current threshold;

a comparative statement to verify if the intake pressure is less than a pressure threshold;

a comparative statement to verify if the coefficient of determination of the intake pressure is greater than a threshold constant; and

a comparative statement to verify if the slope value of a linear approximation of the intake pressure is greater than a slope threshold.

11. The method of claim 1 , wherein the output comprises a binary value.

12. A system comprising:

at least one processor;

a memory communicatively coupled to the at least one processor;

a database having a plurality of rules, stored in the memory, wherein the rule is indicative of a standard operating condition of a subsurface electrical device; and

an analytic engine stored in the memory and executable by the at least one processor and configured to:

select a measured parameter from a sensor coupled to the subsurface electrical device;

obtain a plurality of samples for the measured parameter;

remove at least one invalid sample from the plurality of samples based on a predefined sample criteria to generate a remaining number of samples;

compute a diagnostic parameter based on the remaining number of samples from the plurality of samples, when the remaining number of samples is greater than a predefined threshold number, otherwise terminate the execution by the at least one processor;

obtain a rule from the plurality of rules stored in the database, based on the diagnostic parameter;

evaluate whether the computed diagnostic parameter satisfies the obtained rule, to generate an output; and

determine a measured operating condition of the subsurface electrical device based on the output.

13. The system of claim 12 , wherein the analytic engine is configured to receive the measured parameter comprising a plurality of measured parameters including vibration, supply current, intake pressure, supply voltage, and leakage current, and compute the diagnostic parameter comprising a plurality of diagnostic parameters including an amplitude, a difference value, a mean, a median, a variance, a log likelihood ratio, a slope value, and a coefficient of determination of each measured parameter.

14. The system of claim 13 , wherein the analytic engine is configured to determine the standard and measured operating conditions of the subsurface electrical device, comprising a plurality of operating conditions comprising an excessive vibration, an emulsion pattern, a broken shaft fault, a motor insulation damage, and a pump failure.

15. The system of claim 14 , wherein the analytic engine is configured to evaluate the rule for determining the excessive vibration comprising:

a comparative statement to verify if the amplitude of the vibration is less than a first amplitude threshold; and

a comparative statement to verify if the amplitude of the vibration is greater than a second amplitude threshold.

16. The system of claim 14 , wherein the analytic engine is configured to evaluate the rule for determining the emulsion pattern comprising:

a comparative statement to verify if the supply current is greater than a current threshold;

a comparative statement to verify if the variance of the supply current is greater than a current variance threshold; and

a comparative statement to verify if the variance of the intake pressure is greater than a pressure variance threshold.

17. The system of claim 14 , wherein the analytic engine is configured to evaluate the rule for determining the broken shaft fault comprising:

a comparative statement to verify if the supply current is greater than a current threshold;

a comparative statement to verify if the log likelihood ratio is greater than a likelihood threshold; and

a comparative statement to verify if the difference value is less than a difference threshold.

18. The system of claim 14 , wherein the analytic engine is configured to evaluate the rule for determining the motor insulation damage comprising:

a comparative statement to verify if a difference between two successive sample values of the leakage current is less than a leakage current threshold;

a comparative statement to verify if the leakage current is a non-zero value; and

a comparative statement to verify if a difference between a first median of one set of sample values of the leakage current and a second median of another set of sample values of the leakage current is greater than a median threshold.

19. The system of claim 14 , wherein the analytic engine is configured to evaluate the rule for determining the pump failure comprising:

a comparative statement to verify if the supply current is greater than a current threshold;

a comparative statement to verify if the intake pressure is less than a pressure threshold;

a comparative statement to verify if the coefficient of determination of the intake pressure is greater than a threshold constant; and

a comparative statement to verify if the slope value of a linear approximation of the intake pressure is greater than a slope threshold.

20. The system of claim 12 , wherein the analytic engine is configured to generate the output comprising a binary value.

21. A non-transitory computer readable medium encoded with a program to instruct at least one processor to:

select a measured parameter from a sensor coupled to a subsurface electrical device;

obtain a plurality of samples for the measured parameter;

remove at least one invalid sample from the plurality of samples of the measured parameter to generate a remaining number of samples, wherein the at least one invalid sample is based on a predefined criteria;

compute a diagnostic parameter based on the remaining number of samples from the plurality of samples, if the remaining number of samples is greater than a predefined threshold number, otherwise terminate the program;

obtain a rule from a plurality of rules stored in a database, based on the diagnostic parameter, wherein the rule is indicative of a standard operating condition of the subsurface electrical device;

evaluate whether the computed diagnostic parameter satisfies the obtained rule, to generate an output; and

determine a measured operating condition of the subsurface electrical device based on the output.