System and method for detecting heliostat failures using artificial light sources
A system and method for detecting heliostat failures in a concentrating solar plant, the system comprising a plurality of stationary lights and cameras mounted to towers that surround, or are situated within, a field of heliostats. Heliostats may be commanded via a control system to move to a position wherein light may be expected to be reflected from a given stationary light to a given camera, whereupon a first set of images of the heliostat are taken. Heliostats may then be commanded via the control system to move to a position wherein light may no longer be expected to be reflected from said stationary light to said camera, whereupon a second set of images of the heliostat are taken. An image processor may search the first and second set of images to determine if reflected light is present. If reflected light from said stationary light is not found in the images, the heliostat may be determined to have experienced a failure mode. Failed heliostats may then be flagged for inspection, repair, or replacement.
1. A method for detecting heliostat failures, the method comprising a commissioning phase followed by a monitoring phase, wherein the commissioning phase comprises the steps of:
(a) Calibrating a heliostat;
(b) Selecting said heliostat, a camera, and a stationary light and associating them as a heliostat-camera-light triplet;
(c) Determining bright and dark points for said heliostat-camera-light triplet; and
(d) Storing the bright and dark points for said heliostat-camera-light triplet in a database;
and wherein the monitoring phase comprises the steps of:
(a) Selecting a heliostat;
(b) Performing a spot-check test on said heliostat;
(c) Storing the results of said spot-check test in a database;
(d) Processing the results of said spot-check test;
(e) Delivering notification of the results of said spot-check test; and
(f) Adjusting the frequency and sample population of future spot-check tests based on said results.
2. The method of detecting heliostat failures according to claim 1 , wherein the commissioning phase comprises the additional step of administering a pointing test to said heliostat, and wherein said additional step occurs after step (a) and before step (b).
3. The method of detecting heliostat failures according to claim 2 , wherein the commissioning phase comprises the additional step of simulating the expected performance of said heliostat, wherein said additional step occurs after the step of claim 2 and before step (b).
4. The method of detecting heliostat failures according to claim 1 , wherein said spot-check test comprises the steps of:
(a) Commanding said heliostat to move to the position of a bright point using a control system;
(b) Taking, with the camera, a first sequence of images of the heliostat;
(c) Commanding said heliostat to move to the position of a dark point using a control system;
(d) Taking, with the camera, a second sequence of images of the heliostat;
(e) Cropping, using an image processor, said first and second sequences of images to only include regions where said heliostat is present; and
(f) Determining if reflected light from the heliostat is present in the first and second sequences of images.
5. The method of claim 4 , wherein determining if reflected light from the heliostat is present in the cropped image is achieved by a feature recognition algorithm.
6. The method of claim 1 , wherein the bright points comprise heliostat motor positions that result in a reflection of said stationary light from said heliostat onto said camera.
7. The method of claim 1 , wherein the dark points comprise heliostat motor positions that do not result in a reflection of said stationary light from said heliostat onto said camera.
8. The method of claim 1 , wherein the bright and dark points are separated from each other in an axial direction by less than 1 milliradian.
9. The method of claim 1 , wherein said heliostat is determined to have experienced a failure mode if it fails said spot-check test.
10. The method of claim 1 , wherein the method is performed at night-time.
11. The method of claim 1 , wherein the results of said spot-check test are delivered to a user.
12. The method of claim 1 , wherein the results of said spot-check test are delivered to an automated software application.