How to Diagnose the Root Cause of Harmonics Before the Customer Calls
By Matt Valenti, Application Engineer
Following the interest garnered by our last blog overviewing harmonics, this piece is the first in a three-part series diving deeper into the real-world impact of these distortions on utility operations and infrastructure. In our previous post, we discussed how harmonics are quietly stressing the grid. Here we dig into a frustrating scenario: when you know there’s a harmonics issue but can’t tell where it’s coming from.
Utilities often get caught in the blame game between internal teams and customer equipment. With more rooftop solar, EV chargers and non-linear loads, phase-level harmonic distortion is becoming more common and more elusive. The key to resolving these issues quickly is real-time transformer-level visibility.
Pinpointing the Source of Harmonics
Harmonic distortion doesn’t always show up consistently. The waveform may look clean for hours, then spike without warning. When a customer complains about flickering lights or overheating equipment, sending a crew out with portable meters can take days and still miss the event.
Edge Zero’s EdgeSensor (600 Series) makes this easier:
- Per-phase iTHD and vTHD visibility at the transformer
- Real-time alerts when thresholds are crossed
- Historical trend data for root cause analysis
A commercial site that installs new LED lighting may start experiencing flicker and voltage anomalies. With EdgeSensor data, you could:
- See that iTHD spikes on phase B match load increases at the site
- Confirm the issue comes from downstream not upstream
- Set targeted alerts so you’re notified if it happens again
Compare that to the traditional process:
- Deploy a logger for a few days
- Wait for the issue to recur
- Analyze the data later, often without clear results
Why Transformer-Level Monitoring Helps
- Isolates harmonic sources without sending teams into the field
- Ends internal debate over who caused the issue
- Gives customers clear data to explain what went wrong
For a real-world example, see how Vermont Electric Coop used Edge Zero sensors to spot a failing transformer in days.
Key Points
Utilities don’t have time to guess. Transformer-mounted real-time monitoring gives you the data where it matters. By solving harmonic issues faster you can:
- Improve customer satisfaction
- Reduce field visits
- Extend transformer life
Next week in this series: how everyday DERs push your transformers harder than you think.
