Reuters Events recently hosted the PV Operations and Financial Strategies conference 2020 which had a panel on the topic, “Reduce your O&M costs by applying proactive and predictive maintenance.” The panel consisted of industry veterans including, Swarup Mavanoor, CEO and Co-founder, SenseHawk, Julien Glover, Control Center Manager, Cypress Creek Renewables, and Michael Eyman, Managing Director, Origis Services, who shared their expert opinions on predictive maintenance and discussed the techniques used to assess the performance of panels, inverters, and trackers.
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By the end of the discussion, Ms.Edmee Kelsey, CEO of 3megawatt and also the moderator of this event, lefts the floor open to the attendees, who came up with various questions, one of which she directs to the speakers, “What are some good techniques to have been used for predictive analytics for inverter failures?” In an attempt to answer this question, Mr. Michael begins, “I think the most rational and logical entity to effectively do this are the inverter manufacturers, because it begins with designing the inverter with the right data points to see that things are going on. So if you start to see deviations and vibration on your fans, and you notice that the bearings are starting to look bad, you have to get them instrumented in the design phase. Some years ago, Schneider designed an inverter that was heavily instrumented, and brought it to market, and then a year later, they left the market. So it is a challenge in a cost competitive space for the companies to afford creating products that can provide them with the data that they would need to do that at a deeper level. But around inverters, I think only the inverter manufacturers can dig in. So if you are tracking temperature deviations on your cores and your IGBTs at the 10th of a degree or less to see if they are starting to delaminate over time, or you are looking at those types of issues, and you have got temperature sensors all across the unit with their vibrations and test analysis, then you can maybe get to the point of doing that. However, at an operator level, we are not day-to-day going to be able to get down to this detail level to make sense of that. But I think the inverter manufacturers could. If they can get to a point where they can build a product or a service, and can have that make sense financially, then the market would be very interested in that.”
Moving forward to another similar question from the attendees, Ms. Edmee asks, “Is there anything happening on the predictive side on trackers?” Mr. Swarups takes over to answer it, “There is one thing that we have seen, one failure mode is the damper. Every tracker has a damper that prevents the tracker from going awry when there is wind. These dampers being mechanical devices and they fail. But what we have realized is we see a discoloration long before this actual failure occurs. This is primarily because of an oil leak. When you see that slight discoloration, right at the start, you could pick it up. You can fly a drone at dawn or in the evening, just to get the trackers when they are at max angle. We just fly them a certain way, and find the dampers that are looking different from the others.”
Finally, Ms. Edmee takes up one of the last questions, “This question is not necessarily related to predictive maintenance, but has been around for a long time. What processes do you employ to assess that your panels are performing according to warranty?” Mr. Julien shares, “From our end, we do frequent drone flights of our panels, and when issues are found, we typically try and find where the major issues are, and then identify a string to go through and do some testing. Post this, if we see that there is an actual performance issue, where the panel isn’t performing up to what the manufacturer specified, and then from there, we would probably have to expand it and go into a larger investigation of that site, or the multiple sites built around the same time. So it can quickly spiral into a much larger issue, if we do find something like that.”
Mr. Michael adds as a concluding note, “We all kind of follow these same processes. We either have drones internally, or we call SenseHawk or other providers. There are a few technological changes that might bring in shifts, because ideally you have persistence in your surveillance of these systems. The military talks along these terms, but it is also true for these plants. If you can have an infrared and a daytime eye on these plants and look at these things all the time both from underneath and on top, then you can start getting enough data to go ahead of that stuff. However, this is going to take improvements in satellite technology, dirigibles, mass mounted sensors, ground mounted sensors, and the costs are going to have to come down. These will really change the amount of data and how you can go after it.”
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