An inverter can generate a lot of alerts for numerous different reasons. If it starts generating again, some of these alerts will be ‘resolved’. This doesn’t mean the problem has been fixed. Inverter portal noise can itself overwhelm a user and prevent fixing serious issues.
Diagno onboarded a commercial solar installation with many inverters. The initial data looked healthy, and the system was performing at above 80% using our performance benchmarking. When looking at the assets themselves, we started to see a more concerning picture.
Diagno flagged that two inverters at the site weren’t generating some mornings. It became clear quickly that these days were poor-weather or damp. Across Diagno’s fleet, this pattern correlates very well with insulation resistance issues on sites where we’re able to see the measured insulation resistance as well. These issues can arise from a number of causes like moisture ingress, damaged cabling, exposed wires or other physical damage. In this case, a site visit confirmed that there were panels that were smashed and with severe hot-spotting.
Filtering the noise
A cursory look at the inverter’s monitoring portal in the afternoon would yield no active alarms. As soon as the inverter started generating near midday, the rapid insulation resistance errors being raised (263 since the first event!) were marked ‘resolved’. There was nothing in-your-face to tell the client that the inverter had serious insulation issues. Hundreds of errors had been flagged and resolved this way – it was only once Diagno became involved that this was consolidated into a genuine system issue.
The client received a system diagnostic directly from us.
An earth fault was detected starting 30/04/2026 for the site’s SG30CX inverter with serial number XXXXXXXXXX. The inverter’s insulation resistance has been reading as low as 1kOhm on multiple occasions throughout the morning, causing significant delays to start-up and reducing daily generation. This is the second severe earth fault on site, indicating the systems as a whole is experiencing DC side degradation. This earth will likely worsen over time, and represents a safety risk with the potential for equipment damage, electric shock, and fire. We recommend a technician be dispatched as a priority to perform insulation resistance testing on all DC strings to identify the fault location. Please note that low IR faults are worsened by moisture, and testing should be conducted in the early morning or during humid conditions as completely dry weather may temporarily raise IR readings and obscure fault severity.
After this was sent, a technician was dispatched to site and smashed panels and hot-spots were identified. At this first visit, the technician switched off the system. This reduces the risk of further equipment damage, however does not completely remove the risk posed by smashed panels. A further visit had those panels replaced and the system returned to full operation, noise free.
A material outcome out of overwhelming data
Inverter portal noise places a burden on individuals and teams that are concerned about asset safety and performance. Because of this noise, a genuine safety and equipment issue fell through the cracks. Diagno’s pitch here is that we take this burden from you. We make sure that the only data getting to you is what you want to see. Genuine problems, real statistics.
