System and method for decreasing solar collector system losses

• US 7,990,743 B2
• Filed: 10/20/2009
• Issued: 08/02/2011
• Est. Priority Date: 10/20/2009
• Status: Active Grant

• Current Assignee: GE Grid Solutions LLC (GE Aerospace)
• Original Assignee: General Electric Company
• Inventors: Delmerico, Robert William, Miller, Nicholas Wright, Walling, Reigh Allen, Cardinal, Mark Edward
• Primary Examiner(s): Riley; Shawn
• Application Number:
  US12/582,353
• Publication Number:
  US 20100138061A1
• Time in Patent Office: 651 Days
• Field of Search: 323/906, 323/207, 363/71, 136/293, 136/244
• US Class Current: 363/71
• CPC Class Codes: H02J 2300/22 The renewable source being solar energy
• CPC Class Codes: H02J 2300/24 of photovoltaic origin
• CPC Class Codes: H02J 2310/18 The network being internal to a power source or plant
• CPC Class Codes: H02J 3/16 by adjustment of reactive power
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02J 3/46 Controlling of the sharing of output between the generators, converters, or transformers
• CPC Class Codes: H02J 3/50 Controlling the sharing of the out-of-phase component
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers
• CPC Class Codes: Y02E 40/30 Reactive power compensation
• CPC Class Codes: Y10S 323/906 Solar cell systems

Abstract

A solar farm system is provided that is configured for reducing electrical loss. The solar farm system includes a plurality of PV arrays coupled to inverters and a collector system including a conductor or network of conductors. The collector system also includes a plurality of transformers with one or more transformers connected between the inverters and the conductors. The solar farm also includes a substation transformer connecting the solar farm collector system to the electrical grid. The solar farm includes a control system configured to determine at least one operating parameter for the solar farm system to reduce electrical loss and to regulate the collector system and the plurality of inverters based at least in part on the at least one operating parameter.

Claims

1. A solar farm system, comprising:

a plurality of inverters, each said inverter supplying AC power from at least one photovoltaic array;

a collector system comprising at least one conductor, said plurality of inverters being coupled to the at least one conductor;

a substation transformer connecting said collector system through a point of common coupling to an electrical grid; and

,

a control system configured to determine at least one operating parameter for said solar farm system to reduce electrical loss, said control system configured to regulate at least one of said collector system and said plurality of inverters based at least in part on the at least one operating parameter;

wherein the at least one operating parameter comprises a collector system voltage at the collector system side of said substation transformer.

2. The solar farm system of claim 1, wherein the electrical loss comprises conduction loss and no-load excitation loss.

3. The solar farm system of claim 1, wherein the at least one operating parameter further comprises a reactive power distribution for said plurality of inverters, said control system configured to regulate the reactive power output of at least one of said inverters based on the determined reactive power distribution.

4. The solar farm system of claim 3, wherein the reactive power distribution is determined based at least in part by shifting reactive power to inverters closest to the point of common coupling.

5. The solar farm system of claim 3, wherein said control system is configured to determine the reactive power distribution based at least in part on system constraints, the system constraints comprising maintaining at least one of a power factor, power flow, and voltage at the point of common coupling.

6. The solar farm system of claim 1, wherein the control system is configured to determine the collector system voltage as a function of complex power output by the solar farm system.

7. The solar farm collector system of claim 1, wherein said substation transformer has on-load tap changing capability, said control system being further configured to regulate said substation transformer to execute the determined collector system voltage.

8. The solar farm collector system of claim 1, wherein said control system is configured to determine the collector system voltage based at least in part on system constraints, the system constraints comprising maintaining at least one of a power factor, power flow, and voltage at the point of common coupling.

9. The solar farm collector system of claim 1, wherein said control system is configured to implement an algorithm whose technical effect is reducing electrical losses for the solar farm system.

10. The solar farm collector system of claim 9, wherein the algorithm comprises:

determining a reactive power distribution for said inverters based at least in part by shifting reactive power to said inverters closest to the point of common coupling; and

,

determining a collector system voltage as a function of complex power output by the solar farm system.

11. A method for controlling a solar farm system, comprising:

coupling a plurality of inverters to a collector system, the collector system comprising at least one conductor;

coupling the collector system through a point of common coupling to an electrical grid through a substation transformer;

determining at least one operating parameter for the solar farm system to reduce electrical loss; and

,

regulating at least one of the collector system and the plurality of inverters based on the operating parameter;

wherein the at least one operating parameter comprises a collector system voltage at the collector system side of said substation transformer.

12. The method of claim 11, wherein the electrical loss comprises conduction loss and no-load excitation loss.

13. The method of claim 11, wherein determining at least one operating parameter further comprises determining a reactive power distribution for the plurality of inverters, said method comprising regulating the reactive power output of at least one of the inverters based on the determined reactive power distribution.

14. The method of claim 13, wherein determining a reactive power distribution comprises shifting reactive power to inverters closest to the point of common coupling.

15. The method of claim 13, wherein determining a reactive power distribution comprises maintaining at least one of a power factor, power flow, and voltage at the point of common coupling.

16. The method of claim 11, wherein the collector system voltage is determined as a function of complex power output by the solar farm system.

17. The method of claim 11, wherein determining the collector system voltage comprises maintaining at least one of a power factor, power flow, and voltage at the point of common coupling.

18. The method of claim 11, wherein determining at least one operating parameter comprises implementing an algorithm having a technical effect of reducing electrical losses in the solar farm system, the algorithm comprising:

determining a reactive power distribution for the inverters based at least in part by shifting reactive power to inverters closest to the point of common coupling; and

,

determining a collector system voltage as a function of complex power output by the solar farm system.

19. A solar farm system, comprising:

a plurality of inverters, each said inverter supplying AC power from at least one photovoltaic array;

a collector system comprising at least one conductor, said plurality of inverters being coupled to the at least one conductor;

a substation transformer connecting said collector system through a point of common coupling to an electrical grid; and

,

a control system configured to determine at least one operating parameter for said solar farm system to reduce electrical loss, said control system configured to regulate at least one of said collector system and said plurality of inverters based at least in part on the at least one operating parameter;

wherein the at least one operating parameter comprises at least one of a reactive power distribution for said plurality of inverters, the reactive power distribution the reactive power distribution being determined based at least in part by shifting reactive power to inverters closest to the point of common coupling.

20. The system of claim 19, wherein said control system is configured to implement an algorithm whose technical effect is minimizing electrical losses for the solar farm system.