Utility-scale solar installations have the potential to completely transform our relationship with energy by delivering cheap, green electricity—but we're not there yet. Common, preventable ground faults in solar arrays are costing the industry billions of dollars a year, threatening the industry's long-term sustainability and undermining its growth potential.
The solar industry needs to tackle these ground faults head-on with a new, proactive maintenance strategy. Instead of the typical set-and-forget attitude to maintaining solar systems, operators would benefit from a more aggressive approach and a new tool in their belt.
The Cost of Skipping Maintenance
Studies show that a lack of effective maintenance cost the solar industry at least $10 billion in 2024. To get a little more granular, it's estimated that solar operators lose $5,720 per MW due to underperforming equipment. That figure has skyrocketed in recent years—in 2020, solar farms lost an average of $977 per MW. In other words, we're seeing a greater than 200% increase in losses due to maintenance issues.
What explains this trend? One answer is that solar installations have expanded dramatically since 2020, and as the solar farms have scaled, many operators have struggled to scale their maintenance programs accordingly.
Labor shortages have also made solar maintenance more challenging. Maintenance teams continue to be chronically understaffed, and the solar sector is no exception: that's part of what we're seeing in the loss figures. Anecdotally, when I travel to regions where labor is more widely available, solar farms are more productive and experience less downtime—thanks to the large maintenance crews on-site.
The good news is, you don't actually need a huge maintenance crew to effectively maintain a solar farm. Lean crews can be highly effective, as long as they have the right approach and the right tools. Approaching solar maintenance like a hunter means equipping yourself with technology that can trace ground faults and prevent arc fault fires, all from a safe distance. The result, of course, is greater uptime and productivity for your entire solar installation, without the cost and danger involved in older approaches to maintenance.
With the right tools in their belts, lean crews can achieve great results hunting, tracking, and eliminating ground faults. It all starts with setting priorities.
Hunting with Purpose
Utility-scale solar farms are subject to a wide range of issues, from cracked modules and loose wiring to ground and arc fault fires. Where should operators focus their energy?
Many solar operators already follow a basic preventive maintenance program, with routine cleaning, drone scans, and visual inspections. Most operators need to focus their energy on addressing ground faults. Until recently, this has been a major challenge, especially for lean maintenance teams. That's where modern technology comes in.
Ground faults are among the most persistent, challenging issues faced by solar operators. Left uncorrected, they can lead to dangerous electrical fires, injuring workers and damaging equipment. Tracking them down and repairing them should be one of the top priorities for solar fault hunters. And fortunately, new tools make that easy.
Fluke Corporation
Hunting and Tracking Ground Faults
Ground faults are elusive. To put it in hunting terms, they are tough prey to track down; they easily camouflage themselves among the many strings in an array.
Modern inverters feature built-in ground fault detection and interruption devices that shut down the inverter immediately upon detecting a ground fault. This is a crucial safety measure that protects people and equipment from electrical hazards and fires. However, the inverter's ground fault detection system isn't designed to pinpoint the exact location of the fault.
Traditionally, technicians have used a laborious "brute force" approach to pinpoint ground faults. The brute force approach requires technicians to spend hours measuring voltage levels and testing insulation resistance, string by string, to isolate the string with the ground fault.
Faced with this prospect, many technicians decide to simply take the whole string offline. That's a tempting choice, since it means technicians no longer have to track down hard-to-locate ground faults, and they can get the inverter online faster.
However, isolating the string means that the section of the array does not generate electricity. It can lead to significant revenue drops, and (depending on your service agreement) fines for failing to meet uptime guarantees.
Uncorrected ground faults also pose safety hazards. Even if you take a string offline, a secondary ground fault nearby can create a circular current that runs through the old faulty string, creating electrical hazards and, in many cases, fires.
The Hunter's New Tools
In the vast majority of cases, the hard part of ground fault troubleshooting is pinpointing the fault's location. Once they're identified and located, repairs are fairly easy.
Thanks to advances in technology, solar technicians are now able to quickly and safely hunt down electrical faults in a utility-scale solar array. Troubleshooting ground faults, which used to require hours of skilled labor, can now be completed in a fraction of that time. The newest tools also require less training and experience to operate, which is a huge benefit for expertise-constrained teams.
Here's how they work.
As we've seen, inverters shut down as soon as a ground fault is detected.
Will White, Senior Application Specialist, Fluke Corporation
Depending on how the system is designed, the entire process (including setting up the transmitter) may be done outside the electrical hazard zone, allowing technicians to stay safe while they hunt down faults.
The best of the new tools come with mapping functions, so technicians can see exactly where each string is located. Built-in analytic functions also make the tools more intuitive to use and easier to learn than previous testing techniques, allowing new employees to deploy them successfully after a brief training period.
The results are clear. Innovative technology is enabling a new, proactive approach to maintaining utility-scale solar arrays. Taking on a hunter's stance allows technicians to get ahead of potentially dangerous ground faults before they cause damage. Proactively locating and repairing ground faults means increased uptime and productivity, with a lower operational cost. It's a win for solar fault hunters and for everyone using the energy they produce.
