Weather tracking in a photovoltaic energy generation system

Patent metadata

Field	Value
Publication number	US-10359797-B2
Application number	US-201514960271-A
Country	US
Kind code	B2
Filing date	Dec 4, 2015
Priority date	Apr 30, 2015
Publication date	Jul 23, 2019
Grant date	Jul 23, 2019

Abstract

A computer-implemented method includes receiving power measurement data for a photovoltaic (PV)-based energy generation (EG) sites, determining if cloud cover is present over the EG site based on a difference between a present and historical power output for the EG site, calculating a density of the cloud cover over the EG site based on the present and historical power outputs, and controlling load characteristics of the EG site based on the determined presence and calculated density of the cloud cover. The density of the cloud cover is based on a percentage difference in power output between the present power output and the historical power output. A vector for the cloud cover can be determined based on movement of a detected storm system with a boundary defined by a location of a plurality of EG sites, or by a movement of the cloud density from one EG site to the next.

First claim

What is claimed is:

1. A computer-implemented method comprising:
receiving, by a processor, power measurement data for a photovoltaic (PV)-based energy generation (EG) site, the power measurement data including:
a present power output of the EG site; and
a historical power output of the EG site;
determining whether cloud cover is present over the EG site based on the present and historical power outputs for the EG site;
calculating a density of the cloud cover over the EG site based on the present and historical power outputs for the EG site; and
controlling a charging profile of one or more energy storage devices of the EG site based on the determined presence and calculated density of the cloud cover,
wherein the charging profile for the one or more energy storage devices includes an increased charge set point when cloud cover is determined to be present than when cloud cover is determined not to be present and the cloud cover density is greater than a predetermined threshold value for cloud density, and
wherein the charging profile for the one or more energy storage devices includes a higher charge rate when cloud cover is determined to be present than when cloud cover is determined not to be present.

2. The method of claim 1 wherein the power measurement data corresponding to the present power output of the EG site is received from the EG site, and
wherein the power measurement data corresponding to the historical power output of the EG site is received from a database.

3. The method of claim 1 wherein the historical power output is an average power output for the EG site for a previous period of time.

4. The method of claim 1 further comprising:
calculating a difference between the present power output and the historical power output for the EG site, wherein cloud cover is determined to be present over the EG site when the difference between the present power output and historical power output of the EG site is greater than a predetermined threshold value for cloud cover.

5. The method of claim 1 wherein calculating the density of the cloud cover is based on a percentage difference in power output between the present power output and the historical power output.

6. The method of claim 1 wherein the controlled load characteristics of the EG site further include a time-shifting load profile of the EG site.

7. The method of claim 1 further comprising: receiving weather forecast data;
determining a vector of the determined cloud cover based on the weather forecast data;
determining one or more EG sites in a path of the cloud cover based on the determined vector; and
controlling load characteristics of the one or more EG sites in the path of the cloud cover based on the determined presence and calculated density of the cloud cover over the EG site.

8. A system comprising:
one or more processors; and
one or more non-transitory computer-readable storage mediums containing instructions configured to cause the one or more processors to perform operations including:
receiving, by a processor, power measurement data for a photovoltaic (PV)-based energy generation (EG) site, the power measurement data including:
a present power output of the EG site; and
a historical power output of the EG site;
calculating a difference between the present power output and the historical power output for the EG site;
determining whether cloud cover is present over the EG site based on the difference between the present and historical power outputs for the EG site;
calculating a percentage difference between the present power output and the historical power output for the EG site;
calculating a density of the cloud cover over the EG site based on a percentage difference between the present and historical power outputs for the EG site; and
controlling a charging profile for an energy storage device associated with the EG site based on the determined presence and density of the cloud cover over the EG site,

wherein the charging profile for the energy storage device includes an increased charge set point when cloud cover is determined to be present than when cloud cover is determined not to be present and the cloud cover density is greater than a predetermined threshold value for cloud density, and
wherein the charging profile for the energy storage device includes a higher charge rate when cloud cover is determined to be present than when cloud cover is determined not to be present.

9. The system of claim 8 wherein the power measurement data corresponding to the present power output of the EG site is received from the EG site, and
wherein the power measurement data corresponding to the historical power output of the EG site is received from a database.

10. The system of claim 8 wherein the historical power output is an average power output for the EG site for a previous predetermined period time.

11. The system of claim 8 further comprising:
receiving weather forecast data;
determining a vector of the determined cloud cover based on the weather forecast data;
determining one or more EG sites in the path of the cloud cover based on the determined vector; and
controlling load characteristics of the one or more EG sites in the path of the cloud cover based on the determined presence and calculated density of the cloud cover over the EG site.

12. A computer-implemented method comprising:
receiving, by a processor, power measurement data for a plurality of photovoltaic (PV)-based energy generation (EG) sites, wherein the power measurement data includes:
a present power output of each of the plurality of EG sites; and
a historical power output of each of the plurality of EG sites;
calculating, by the processor, a density of cloud cover over each EG site based on a percentage difference between a present power output and historical power output for the corresponding EG site;
determining, by the processor, that a density of cloud cover at a first EG site of the plurality of EG sites exists at a second EG site of the plurality of EG sites after a period of time;

calculating, by the processor, a vector path for the cloud cover based on:
a location of the first EG site;
a location of the second EG site; and
the period of time;
determining, by the processor, a third EG site of the plurality of EG sites having a location in the vector path of the cloud cover; and
controlling a charging profile for one or more energy storage devices of the third EG site based on a forecasted effect of a power output of the third EG site,
wherein the charging profile for the one or more energy storage devices of the third EG site includes an increased charge set point when the third EG site is located in the vector path of the cloud cover than when the third EG site is not located in the vector path of the cloud cover, and
wherein the charging profile for the one or more energy storage devices of the third EG site includes a higher charge rate when the third EG site is located in the vector path of the cloud cover than when the third EG site is not located in the vector path of the cloud cover.

13. The method of claim 12 further comprising:
controlling, by the processor, an EG distribution profile for the third EG site based on the forecasted effect.

14. The method of claim 12 wherein the density of cloud cover at the first EG site exists at the second EG site when the density of cloud cover at the second EG site is within a threshold tolerance of the density of cloud cover at the first EG site.

15. The method of claim 12 wherein the vector path is calculated based on:
a distance between th

Assignees

• Solarcity Corp

Inventors

• Carlson Eric Daniel

Classifications

• H02J2103/30

  Simulating, planning, modelling, reliability check or computer assisted design [CAD] of electric power networks · CPC title

• H02J2101/24

  Photovoltaics · CPC title

• H02J2101/22

  Solar energy · CPC title

• H02J13/12

  Monitoring network conditions, e.g. electrical magnitudes or operational status · CPC title

• H02J7/90

  Regulation of charging or discharging current or voltage · CPC title