SYSTEM AND METHOD FOR OPERATING A TAP CHANGER

• US 20120249278A1
• Filed: 03/31/2011
• Published: 10/04/2012
• Est. Priority Date: 03/31/2011
• Status: Active Grant

• Current Assignee: GE Infrastructure Technology, LLC (GE Vernova, Inc.)
• Original Assignee: General Electric Company
• Inventors: Krok, Michael Joseph, Genc, Sahika
• Granted Patent: US 8,531,173 B2
• Time in Patent Office: Days
• US Class Current: 336/150
• CPC Class Codes: G05F 1/14 using tap transformers or tap changing inductors as final control devices
• CPC Class Codes: H02J 3/00 Circuit arrangements for ac mains or ac distribution networks
• CPC Class Codes: H02J 3/003 Load forecast, e.g. methods or systems for forecasting future load demand
• CPC Class Codes: H02J 3/16 by adjustment of reactive power
• CPC Class Codes: H02J 3/1878 using tap changing or phase shifting transformers
• CPC Class Codes: H02P 13/06 by tap-changing; by rearranging interconnections of windings
• CPC Class Codes: Y02E 40/30 Reactive power compensation
• CPC Class Codes: Y04S 10/50 Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications

Abstract

A method of operating a tap changer of a transformer or a voltage regulator in a power grid includes obtaining a load forecast for a time period. An average voltage profile is determined for the time period based on the load forecast. The method further includes estimating tap positions of the tap changer for leveling the average voltage profile during the time period. Switching signal commands are provided to the tap changer based on the estimated tap positions.

Claims

1. A method of operating a tap changer of a transformer or a voltage regulator in a power grid comprising:

obtaining a load forecast for a time period;

determining an average voltage profile for the time period based on the load forecast;

estimating tap positions of the tap changer for leveling the average voltage profile during the time period; and

providing switching signal commands to the tap changer based on the estimated tap positions.

2. The method of claim 1, wherein the load forecast comprises active and reactive power forecasts.

3. The method of claim 1, wherein the time period comprises a time determined by an operator including an hour, a day or a week.

4. The method of claim 1, wherein determining the average voltage profile comprises determining an average of node voltages for a phase in a zone.

5. The method of claim 4, wherein the zone comprises a network between two tap changers.

6. The method of claim 1, wherein determining the average voltage profile comprises running a load flow algorithm on the load forecast.

7. The method of claim 1, wherein leveling the average voltage profile comprises determining a flat voltage value for the time period.

8. The method of claim 7, wherein tap positions are based on the average voltage profile, the flat voltage value and a voltage value per tap.

9. The method of claim 7, wherein the flat voltage value comprises a predetermined voltage value.

10. The method of claim 9, wherein the predetermined voltage value may be determined based on conservation voltage reduction factor.

11. The method of claim 7, wherein the flat voltage value is determined to minimize tap position changes.

12. The method of claim 7, wherein the flat voltage value comprises an average value or a median value of a minimum and a maximum voltages of the voltage profile.

13. A tap changer control system comprising:

a load forecasting module to determine a load forecast for a time period;

a load flow module to determine an average voltage profile for the time period of interest;

a tap position identification module to estimate tap positions of a tap changer of a transformer or a voltage regulator for leveling the average voltage profile; and

a switching circuitry to adjust taps of the tap changer based on the estimated tap positions.

14. The system of claim 13, wherein the load forecast comprises active and reactive power forecasts.

15. The system of claim 13, wherein the average voltage profile comprises an average of node voltages for a phase in a zone.

16. The system of claim 15, wherein the zone comprises a network between two tap changers.

17. The system of claim 13, wherein the load flow module comprises a numerical method to obtain average voltages over the time period.

18. The system of claim 13, wherein leveling the average voltage profile comprises determining a flat voltage value for the time period.

19. The method of claim 18, wherein tap positions are based on the average voltage profile, the flat voltage value and a voltage value per tap.

20. A computer-readable medium comprising non-transitory computer-readable instructions that, when executed by a processor, cause the processor to perform a method of operating a tap changer of a transformer or a voltage regulator in a power grid, the method comprising:

obtaining a load forecast for a time period;

determining an average voltage profile for the time period based on the load forecast;

estimating tap positions of the tap changer for leveling the average voltage profile during the time period; and

providing switching signal commands to tap changer based on the estimated tap positions.