Tech Tip

PQ Testing: The Overlooked Step That Can Save Your Solar Investment

PQ testing for solar grids
23
Jun

As solar PV installations expand, performance expectations and ROI are understandably front and center. But there’s one step that often gets skipped, and it’s one that can cost you down the line: evaluating power quality (PQ).

This Application Note explains why PQ assessments are critical before and after solar installation commissioning. It highlights the importance of catching grid or site-specific issues early and ensuring your solar equipment performs as expected without introducing costly electrical disturbances.

Take the rooftop PV system in Xalapa, Mexico, which is featured in the App Note. Engineers installed two inverters feeding 16kW AC output. Using the Seaward PV210 IV-curve tracer, they caught a defect in one of the solar strings, an issue that could have quietly reduced performance. Then, using the Dranetz HDPQ Xplorer Plus, they found high harmonic distortion at the inverter output, well above IEEE 519 limits. This was paired with a 120Hz oscillation, likely due to significant second order harmonics, raising questions about system integrity.

What’s the takeaway? Without pre and post-installation PQ testing, it’s hard to know whether these issues came from the system, the grid, or both. And that uncertainty can delay fixes, inflate costs, or threaten compliance.

Stay Out of Trouble with These Best Practices for Solar

Dranetz and Seaward recommend these best practices:

  • Test PQ before and after commissioning to isolate responsibility.
  • Schedule annual PQ audits to validate ongoing system health.
  • Integrate PQ results into warranty and compliance documentation.
  • Correlate performance metrics with PQ data to uncover root causes.
  • Consider permanent PQ metering at high-risk or critical facilities.

These steps help you find issues as well as help prevent them. PQ evaluations keep solar investments reliable and reduce risk for everyone involved.

If you’re managing or planning a solar deployment, don’t ignore power quality PQ. Treat it as your insurance policy against downtime and dispute.

For more field examples and tools, visit the Dranetz Technical Documents page.