Methods for reducing solar inverter output volatility, and related nodes and solar inverters

• US 9,507,364 B2
• Filed: 03/10/2014
• Issued: 11/29/2016
• Est. Priority Date: 03/10/2014
• Status: Active Grant

• Current Assignee: Duke Energy Corporation
• Original Assignee: Duke Energy Corporation
• Inventors: Sowder, Daniel B.
• Primary Examiner(s): Fleming, Fritz M
• Application Number:
  US14/202,854
• Publication Number:
  US 20150253797A1
• Time in Patent Office: 995 Days
• Field of Search: 307/125
• US Class Current: 1/1
• CPC Class Codes: G05F 1/67 to the maximum power available from a generator, e.g. from solar cell
• CPC Class Codes: H02J 2300/24 of photovoltaic origin
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02S 40/32 comprising DC/AC inverter means associated with the PV module itself, e.g. AC modules
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers

Abstract

Methods for reducing solar inverter output volatility are provided. A method for reducing solar inverter output volatility may include determining whether an output fluctuation by a solar inverter is likely, using output data of the solar inverter. Moreover, the method may include curtailing an output of the solar inverter in response to determining that the output fluctuation by the solar inverter is likely. Related solar inverters and solar installation nodes are also described.

Claims

1. A method for reducing solar inverter output volatility, the method comprising:

determining whether an output fluctuation by a solar inverter is likely, using output data of the solar inverter; and

curtailing an output of the solar inverter in response to determining that the output fluctuation by the solar inverter is likely,

wherein determining whether the output fluctuation is likely comprises;

determining a volatility difference for the solar inverter, the volatility difference comprising a ratio between;

an end-to-end straight linear distance corresponding to a graphical representation of power output by the solar inverter over a time period; and

a summation of a plurality of linear distances corresponding to the graphical representation of power output by the solar inverter over a plurality of respective sub-time-periods of the time period.

2. The method of claim 1, wherein determining whether the output fluctuation is likely comprises:

determining a likelihood of the output fluctuation by the solar inverter, using the output data of the solar inverter; and

comparing the likelihood of the output fluctuation by the solar inverter with a threshold.

3. The method of claim 1,

wherein the output data of the solar inverter comprises real-time and/or past output data of the solar inverter, and

wherein determining whether the output fluctuation by the solar inverter is likely comprises:

determining whether the output fluctuation by the solar inverter is likely, using the real-time and/or past output data of the solar inverter.

4. The method of claim 3,

wherein the output fluctuation comprises a future output fluctuation, and

wherein determining whether the output fluctuation by the solar inverter is likely comprises:

determining whether the future output fluctuation by the solar inverter is likely, using the real-time and/or past output data of the solar inverter.

5. The method of claim 3, wherein determining whether the output fluctuation by the solar inverter is likely comprises:

determining whether the output fluctuation by the solar inverter is likely, using the real-time and/or past output data of the solar inverter, independently of any measurement or detection by a cloud-cover sensor or another inverter.

6. The method of claim 3, further comprising measuring the real-time and/or past output data of the solar inverter by measuring power that is output by the solar inverter, wherein determining whether the output fluctuation by the solar inverter is likely comprises:

determining whether the output fluctuation by the solar inverter is likely, using only the real-time and/or past output data of the solar inverter.

7. The method of claim 6,

wherein the real-time and/or past output data of the solar inverter comprises at least one discrete value of real-time and/or past output of the solar inverter, and

wherein determining whether the output fluctuation by the solar inverter is likely comprises:

determining whether the output fluctuation by the solar inverter is likely, using only the at least one discrete value of real-time and/or past output of the solar inverter.

8. The method of claim 1, wherein operations of determining whether the output fluctuation by the solar inverter is likely and curtailing the output of the solar inverter are self-contained within the solar inverter.

9. The method of claim 1,

wherein determining whether an output fluctuation by the solar inverter is likely comprises:

generating, at a node of a solar installation that includes the solar inverter, the output data of the solar inverter by measuring power that is output by the solar inverter; and

determining, at the node, whether the output fluctuation by the solar inverter is likely, using the output data of the solar inverter, and wherein curtailing the output of the solar inverter comprises;

transmitting a curtailment command to limit the output of the solar inverter, from the node to the solar inverter, in response to determining that the output fluctuation by the solar inverter is likely.

10. The method of claim 1, further comprising gradually reducing an amount of curtailment of the output of the solar inverter.

11. The method of claim 1, wherein determining whether the output fluctuation is likely comprises:

determining whether the output fluctuation by the solar inverter is likely, independently of Maximum Power Point Tracking for the solar inverter.

12. A node of a solar installation, the node comprising:

a processor configured to;

generate output data by measuring power that is output by a solar inverter of the solar installation;

determine whether an output fluctuation by the solar inverter is likely, using the output data from the solar inverter; and

transmit, to the solar inverter, a curtailment command to limit the output of the solar inverter, in response to determining that the output fluctuation by the solar inverter is likely,

wherein the processor is configured to determine whether the output fluctuation is likely by;

determining a volatility difference for the solar inverter, the volatility difference comprising a ratio between;

an end-to-end straight linear distance corresponding to a graphical representation of solar output by the solar inverter over a time period; and

a summation of a plurality of linear distances corresponding to the graphical representation of solar output by the solar inverter over a plurality of respective sub-time-periods of the time period.

13. The node of claim 12, wherein the processor is configured to determine whether the output fluctuation by the solar inverter is likely by:

determining a likelihood of the output fluctuation by the solar inverter, using the output data from the solar inverter; and

comparing the likelihood of the output fluctuation by the solar inverter with a threshold.

14. The node of claim 12,

wherein the output data of the solar inverter comprises real-time and/or past output data of the solar inverter, and

wherein the processor is configured to determine whether the output fluctuation by the solar inverter is likely, using the real-time and/or past output data of the solar inverter.

15. The node of claim 14,

wherein the output fluctuation comprises a future output fluctuation, and

wherein the processor is configured to determine whether the output fluctuation by the solar inverter is likely by:

determining whether the future output fluctuation by the solar inverter is likely, using the real-time and/or past output data of the solar inverter.

16. A solar inverter, comprising:

circuitry configured to provide a power output; and

a processor configured to;

receive, from a node of a solar installation that includes the solar inverter, a curtailment command to preemptively limit the power output of the solar inverter in advance of a likely fluctuation of the power output; and

preemptively limit the power output of the solar inverter in advance of the likely fluctuation of the power output, in response to the curtailment command from the node of the solar installation,

wherein the curtailment command is based on a volatility difference for the solar inverter, the volatility difference comprising a ratio between;

an end-to-end straight linear distance corresponding to a graphical representation of solar output by the solar inverter over a time period; and

a summation of a plurality of linear distances corresponding to the graphical representation of solar output by the solar inverter over a plurality of respective sub-time-periods of the time period.

17. The solar inverter of claim 16, wherein the processor is configured to receive the curtailment command directly from the node via a message bus that is within the solar installation.

18. A solar inverter, comprising:

circuitry configured to provide a power output; and

a processor configured to;

determine whether a fluctuation of the power output is likely, using real-time and/or past output data for the solar inverter; and

preemptively limit the power output of the solar inverter in advance of the fluctuation of the power output, in response to determining that the fluctuation of the power output is likely,

wherein the processor is configured to determine whether the fluctuation is likely by;

determining a volatility difference for the solar inverter, the volatility difference comprising a ratio between;

an end-to-end straight linear distance corresponding to a graphical representation of solar output by the solar inverter over a time period; and

a summation of a plurality of linear distances corresponding to the graphical representation of solar output by the solar inverter over a plurality of respective sub-time-periods of the time period.