Project Name: Spread Spectrum Time Domain Reflectivity for String Monitoring in Photovoltaic Power Plants
Funding Opportunity: PVRD2
SETO Subprogram: Photovoltaics
Location: Salt Lake City, UT
SETO Award Amount: $675,000
Awardee Cost Share: $90,000
Principal Investigator: Michael Scarpulla

This project is investigating the application of Spread Spectrum Time Domain Reflectivity (SSTDR) to monitor operating strings of modules in large photovoltaic (PV) arrays. SSTDR can detect, and spatially localize, changes in the impedance of the system in real-time, including at high voltages and currents. This allows monitoring of intermittent and slowly-evolving degradation and failure modes, and potentially enables more efficient characterization of PV power plants, which will maximize future energy output, reduce the levelized cost of electricity, and increase bankability.

The research team is developing measurement and data analysis techniques applicable to short- and long-term SSTDR monitoring of operating strings of modules. An evaluation is also being conducted on the potential of SSTDR to detect transient and sudden-onset electrical faults and determine their location before existing protection systems shut off the string. The team is also engaging PV industry stakeholders to determine how SSTDR monitoring can most effectively lower the levelized cost of electricity. 

This project will enable utility-scale solar operators to easily determine which panel or section of wiring has experienced a physical or operational change. The technology under development is approximately the size of a credit card, which will allow it to be incorporated into next-generation string power electronics. This will allow efficient maintenance and stewardship of PV power plants, maximizing energy output and increasing bankability.