Voltage regulation for multi-phase power systems

Patent metadata

Field	Value
Publication number	US-10177672-B2
Application number	US-201715480784-A
Country	US
Kind code	B2
Filing date	Apr 6, 2017
Priority date	Apr 8, 2016
Publication date	Jan 8, 2019
Grant date	Jan 8, 2019

Abstract

A power system can include a first tap changer for a first regulated transformer, where the first tap changer has a plurality of first positions. The power system can also include a second tap changer for a second regulated transformer, where the second tap changer has a plurality of second positions. The power system can further include at least one first instrument transformer coupled to the first regulated transformer. The power system can also include at least one second instrument transformer coupled to the second regulated transformer. The power system can further include a controller coupled to the at least one first instrument transformer and the at least one second instrument transformer, where the controller adjusts the first tap changer to a first adjusted position among the first positions based on the first measurements of the first regulated transformer and the second measurements of the second regulated transformer.

First claim

What is claimed is:

1. A three-phase electrical power system comprising:
a first tap changer for a first regulated transformer, wherein the first tap changer has a plurality of first positions for regulating a first voltage between a first electrical phase and a second electrical phase;
a second tap changer for a second regulated transformer, wherein the second tap changer has a plurality of second positions for regulating a second voltage between the second electrical phase and a third electrical phase;
at least one first instrument transformer coupled to the first regulated transformer, wherein the at least one first instrument transformer harvests a plurality of first measurements of the first regulated transformer;
at least one second instrument transformer coupled to the second regulated transformer, wherein the at least one second instrument transformer harvests a plurality of second measurements of the second regulated transformer; and
a controller coupled to the at least one first instrument transformer and the at least one second instrument transformer, wherein the controller:
receives the plurality of first measurements from the at least one first instrument transformer and the plurality of second measurements from the at least one second instrument transformer;
analyzes the plurality of first measurements and the plurality of second measurements;
determines, based on analyzing the plurality of first measurements and the plurality of second measurements, that an out-of-band condition exists;
calculates, using the plurality of first measurements and the plurality of second measurements, at least one first setting that results in a substantially equal voltage for the first electrical phase, the second electrical phase, and the third electrical phase; and
adjusts the first tap changer from a first position to a first adjusted position among the plurality of first positions to correspond to the at least one first setting,

wherein adjusting the first tap changer to the first adjusted position regulates the first voltage between the first electrical phase and the second electrical phase, regulates a third voltage between the first electrical phase and the third electrical phase, and eliminates the out-of-band condition.

2. The three-phase electrical power system of claim 1 , wherein the controller further adjusts the second tap changer from a second position to a second adjusted position among the second plurality of positions based on the plurality of first measurements of the first regulated transformer and the plurality of second measurements of the second regulated transformer.

3. The three-phase electrical power system of claim 1 , wherein the first regulated transformer and the second regulated transformer form an open delta configuration.

4. The three-phase electrical power system of claim 1 , wherein the at least one first instrument transformer comprises a current transformer.

5. The three-phase electrical power system of claim 1 , wherein the at least one first instrument transformer further comprises a potential transformer.

6. The three-phase electrical power system of claim 1 , further comprising:
a third tap changer for a third regulated transformer, wherein the third tap changer has a plurality of third positions; and
at least one third instrument transformer coupled to the third regulated transformer, wherein the at least one third instrument transformer harvests a plurality of third measurements of the third regulated transformer,
wherein the at least one first setting is further calculated using the plurality of third measurements of the third regulated transformer.

7. The three-phase electrical power system of claim 6 , wherein the controller further adjusts the third tap changer from the third position to a third adjusted position among the plurality of third positions based on the plurality of first measurements of the first regulated transformer, the plurality of second measurements of the second regulated transformer, and the plurality of third measurements of the third regulated transformer.

8. The three-phase electrical power system of claim 6 , wherein the first regulated transformer, the second regulated transformer, and the third regulated transformer form a closed delta configuration.

9. The three-phase electrical power system of claim 6 , wherein the first regulated transformer, the second regulated transformer, and the third regulated transformer form a grounded wye configuration.

10. The three-phase electrical power system of claim 1 , wherein the controller adjusts the first tap changer from the first position to the first adjusted position based on forward power flows.

11. The three-phase electrical power system of claim 1 , wherein the controller adjusts the first tap changer from the first position to the first adjusted position further based on reverse power flows.

12. The three-phase electrical power system of claim 1 , wherein the controller adjusts the first tap changer from the first position to the first adjusted position further based on a magnitude of calculated values.

13. The three-phase electrical power system of claim 1 , wherein the controller adjusts the first tap changer from the first position to the first adjusted position further based on a phase angle of calculated values.

14. A metering system comprising:
a first tap changer for a first regulated transformer, wherein the first tap changer has a plurality of first positions for regulating a first voltage between a first electrical phase and a second electrical phase;
a second tap changer for a second regulated transformer, wherein the second tap changer has a plurality of second positions for regulating a second voltage between the second electrical phase and a third electrical phase;
at least one first instrument transformer coupled to the first regulated transformer, wherein the at least one first instrument transformer harvests a plurality of first measurements of the first regulated transformer;
at least one second instrument transformer coupled to the second regulated transformer, wherein the at least one second instrument transformer harvests a plurality of second measurements of the second regulated transformer; and
a controller coupled to the at least one first instrument transformer and the at least one second instrument transformer, wherein the controller:
receives the plurality of first measurements from the at least one first instrument transformer and the plurality of second measurements from the at least one second instrument transformer; and
calculates multi-phase power measurements based on the plurality of first measurements of the first regulated transformer and the plurality of second measurements of the second regulated transformer,

wherein the multi-phase power measurements calculated by the controller comprise a first regulated voltage between the first electrical phase and the second electrical phase, a second regulated voltage between the second electrical phase and the third electrical phase, and a third regulated voltage between the first electrical phase and the third electrical phase,
wherein the first regulated voltage corresponds to a first adjusted position of the first tap changer, wherein the second regulated voltage corresponds to a second adjusted position of the second tap changer,
wherein the first regulated voltage, the second regulated voltage, and the third regulated voltage are substantially equal when the first tap changer is in the first adjusted position and when the second tap changer is in the second adjusted position.

15. A method for regulat

Assignees

• Cooper Technologies Co

Inventors

• Daley Daniel Joseph
• Sauer Daniel Michael
• Rapant Fred Joseph

Classifications

• H02J3/26

  Arrangements for eliminating or reducing asymmetry in polyphase networks · CPC title

• G05F1/14

  using tap transformers or tap changing inductors as final control devices · CPC title

• H01F27/402

  Association of measuring or protective means · CPC title

• H02M5/12 Primary

  for conversion of voltage or current amplitude only · CPC title

• H01F29/02

  with tappings on coil or winding; with provision for rearrangement or interconnection of windings · CPC title